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Forest Giants of the Pacific Coast
... Picea is the shortest-lived with the heaviest living tree reaching 76 m tall, 155 Mg biomass, and 480 yr (Kramer et al., 2018), which is 21 m shorter than the tallest living tree (Chin and Sillett, 2017). The heaviest recorded Pseudotsuga tree died during the 20th century after reaching ~900 yr, > 200 Mg biomass, and nearly 120 m tall-greater than any living tree (Carder, 1995;Van Pelt, 2001;Sillett et al., 2018b). Sequoia is currently the tallest and second heaviest with living trees up to 116 m tall, nearly 400 Mg biomass, and > 2000 yr . ...
... Sequoiadendron is the heaviest and longest-lived with extant trees exceeding 96 m tall, 500 Mg biomass, and 3000 yr (Sillett et al., 2019b). Emphasizing the family-level difference in longevity is the fact that since the year 2000 (Van Pelt, 2001), most of the 20 largest known Pinaceae (5 of 10 Picea, 6 of 10 Pseudotsuga) have died, whereas all of the 20 largest known Cupressaceae are alive in 2020. Greater longevity allows Sequoia and Sequoiadendron to grow heavier and to develop larger crowns with more leaves. ...
... Greater tree longevity allows Pseudotsuga to accumulate more biomass than Picea eventually, but shade intolerance and dependence on mineral soil greatly limit Pseudotsuga regeneration in rainforests, resulting in eventual loss of the pioneer cohort as stands transition to dominance by smaller, shade-tolerant species, especially Tsuga heterophylla (Minore, 1979;Franklin et al., 2002;Van Pelt and Nadkarni, 2004). Picea and Pseudotsuga coexist with Sequoia in rainforests farther south where all three species exceed 90 m tall (Van Pelt, 2001;Chin and Sillett, 2019;Fig. 1). ...
The tallest conifers—Picea sitchensis, Pseudotsuga menziesii, Sequoia sempervirens, Sequoiadendron giganteum—are widely distributed in western North America, forming forests > 90 m tall with aboveground biomass ≥ 2000 Mg ha⁻¹. Here we combine intensive measurements of 169 trees with dendrochronology and allometry to examine tree and stand development. The species investing least in bark protection and heartwood defense—P. sitchensis—has more leaves, denser wood, larger appendages, and produces more aboveground biomass during its relatively brief lifespan than other conifers at equivalent ages. The species investing most in bark protection and heartwood defense—S. giganteum—has the least dense wood, largest appendages, and greatest longevity. Evidence for senescence diminishes with longevity; only P. sitchensis exhibits a post-maturity decline in tree productivity after accounting for leaf mass. Growth efficiency declines with age in all species, falling most rapidly in P. sitchensis followed by P. menziesii, S. sempervirens, and S. giganteum in the same sequence as longevity. Centuries-long time series of age, size, and growth increments identify years when trees first reach a given height as well as biomass and growth rates at that height, providing snapshots of performance useful for simulating development. Stands dominated by P. sitchensis and P. menziesii gain height at similar rates, but P. sitchensis accumulates biomass more rapidly until senescence curtails tree productivity, which takes centuries longer in P. menziesii. Whereas S. sempervirens in primary forest grows more slowly than P. sitchensis and P. menziesii until ~70 m tall, S. sempervirens in secondary forest outpaces other conifers with biomass increments approaching global maxima within a few centuries. Beyond ~70 m, S. giganteum gains height more slowly than other conifers, but it sustains relatively high biomass increments for millennia. Both within and beyond their native ranges, the four tallest conifers have unrealized potential to provide ecosystem services.
... The archetypal big tree, Sequoiadendron giganteum (hereafter Sequoiadendron) is renowned as the world's largest species and has been widely celebrated since scientific discovery in the 19th century (Muir, 1878;Clark, 1907;Fry and White, 1930;Flint, 1987;Van Pelt, 2001). Restricted to the Sierra Nevada of California, the native range of Sequoiadendron occupies just 150 km 2 , occurring in distinct groves unlike co-occurring tree species, which have continuous distributions (Griffin and Critchfield, 1972). ...
... Supremely adapted to fire with resin-free bark averaging > 25 cm thick on lower trunks of large trees, Sequoiadendron also produces heartwood that is extremely resistant to fungal decay, enabling in-ground level is killed, treetop water supply is disrupted, explaining the correlation between fire caves and dead tops in Sequoiadendron (Rundel, 1973). Decay-resistant heartwood allows fire-killed tops to persist for centuries on standing trees, whose crowns eventually rebuild around dead spires (Van Pelt, 2001;Sillett et al., 2015a). Even trees whose crowns are mostly destroyed by fire can survive and recover as long as foliage is supported by sufficient wood and maintains adequate connection to roots (Fig. 1). ...
... The greatest anthropogenic change in forest structure is an increase in shade-tolerant conifers, particularly Abies lowiana-formerly A. concolor (Kilgore and Taylor, 1979;Stone, 1980, 1982;Stephenson, 1999), which can exceed 75 m tall, 250 cm diameter at breast height (DBH), and 300 yr age (Van Pelt, 2001). Shade-intolerant shrubs and herbaceous vegetation are also less abundant as a consequence of fire suppression (Kilgore and Biswell, 1971;Harvey et al., 1980). ...
The largest tree species, Sequoiadendron giganteum has a small native range restricted to California’s Sierra Nevada. Awe-inspiring stature contributed to its protection from logging, but anthropogenic climate change—particularly hotter drought—and over a century of fire suppression are possible threats. We measured 60 trees in seven forests to improve allometric equations for the species and installed five 1-ha plots to quantify biomass of Sequoiadendron and associated vegetation. Plots were re-measured after 5 yr to compute biomass increments and examine effects of management history as well as impacts of recent drought. Forests held up to 2683 Mg ha⁻¹ aboveground biomass (1373 Mg C ha⁻¹) and had leaf area index (LAI) up to 14.5 with Sequoiadendron accounting for the bulk of biomass but not LAI. Live trees of other species contributed up to 10.6 LAI and had biomass increments up to 6.1 Mg ha⁻¹ yr⁻¹, but drought contributed to tree mortality in three plots, where live biomass declined by 6.2–10.3 Mg ha⁻¹ yr⁻¹. Two plots had very little tree mortality and gained 5.5–7.9 Mg ha⁻¹ yr⁻¹. Sequoiadendron productivity was strongly correlated with tree-level photosynthetic capacity, but at the height of the drought, relative growth—expressed as the ratio of biomass produced during the driest and wettest recent years—correlated positively with site productivity and negatively with both vertical distance to water and presumed competition from neighboring trees. Prescribed fire in one plot caused a growth release in trees whose lower trunks were burnt and small neighboring Abies lowiana were killed. Effects of 21st century drought on Sequoiadendron productivity were greater in northern than southern locations but of lesser magnitude than many past events. No Sequoiadendron recruitment was observed. Planting can overcome the species’ dependence on fire for regeneration, and Sequoiadendron has great potential for carbon sequestration in a variety of settings, including commercial forestry.
... Across a large portion of its native range, however, surviving old-growth forests have multiple P. menziesii cohorts as a consequence of moderate-severity fires that kill only some of the previous cohort and allow P. menziesii to re-establish (Zenner, 2005;Tepley et al., 2013). In the wettest part of its distribution, long fire-return intervals preclude development of localized seed sources and promote development of extensive forests dominated by other conifers with higher shade-tolerance and lower fire resistance, especially P. sitchensis, Tsuga heterophylla, and Thuja plicata (Franklin and Dyrness, 1988;Beach and Halpern, 2001;Van Pelt, 2001Stolnack and Naiman, 2010). ...
... Understanding of P. menziesii tree and forest development is biased towards the Oregon and Washington Cascades, where the vast majority of research on unlogged forests has occurred. These Cascade forests do not support trees as tall, large, or old as those known from coastal forests at lower elevations (Carder, 1995;Van Pelt, 2001). Except for a few protected areas on the western Olympic Peninsula and in northern California, coastal rainforests with trees > 95 m tall are virtually gone. ...
... Except for a few protected areas on the western Olympic Peninsula and in northern California, coastal rainforests with trees > 95 m tall are virtually gone. To our knowledge, no intensive study of P. menziesii in these forests has The largest individual ever recorded, which grew at 440 m elevation in Lewis County, Washington, was reliably measured at 119.8 m tall and 469 cm DBH (Carder, 1995;Van Pelt, 2001). In addition to total height and lower trunk diameters, a diameter of 183 cm at 68.6 m above the ground was measured on the snapped top in 1908 and verified by an independent observer in 1924 (Boland 1927 photograph from McArdle and Meyer (1930)). ...
One of the five tallest tree species, Pseudotsuga menziesii has enormous economic and ecological importance, but rainforests dominated by this species are not as well understood as their drier montane counterparts. We climbed and measured 30 trees up to 97 m tall growing in coastal forests of the Olympic Peninsula and northern California to quantify structural attributes—leaves, bark, cambium, sapwood, heartwood, deadwood, biomass, growth increments, and age—and combined these with an equal number of trees up to 85 m tall growing in forests of the Cascade Mountains to develop allometric equations based on ground-level predictors. After comparing new equations to those previously published, we applied the best available equations for tall forests to predict aboveground quantities of all vascular plant species in 12 ha of Olympic and Cascade forests. The largest (117 Mg) and one of the oldest (615 years) trees we studied had the highest biomass increment (305 kg yr⁻¹), but age had a negative effect on current and long-term growth increments. After accounting for variation in tree size and aboveground vigor, older trees produced less wood annually and grew less efficiently than younger trees. Size of P. menziesii trees increased more rapidly, and the proportion of biomass and leaf area in P. menziesii decreased more slowly, in Olympic than Cascade forests over six centuries following stand-replacing fire. Maximum aboveground biomass (1999 Mg ha⁻¹) and carbon density (994 Mg ha⁻¹) occurred in a Cascade forest with high abundance of three conifer species (P. menziesii, Tsuga heterophylla, Thuja plicata), but maximum P. menziesii biomass (1289 Mg ha⁻¹) occurred in an Olympic forest with 50 trees ha⁻¹ up to 90 m tall. Vulnerability to wood decay fungi and dependence on fire for stand dominance limit P. menziesii biomass accumulation in rainforests.
... Established in 1929 and later expanded, nearly the entire park is old-growth forest, although it does contain areas of relatively small-stature forests growing on ridges and areas recovering from fire. The 1360 ha of forest having trees >90 m tall includes some of the largest individual trees known (Van Pelt, 2001;Sillett et al., 2015a). With this location and the two that follow, Sequoia occupies nearly all geomorphic surfaces, so upland and lowland plots were established in each forest (shortened to 'up' and 'low' hereafter). ...
... Protected in the early 1920s and later expanded, the park is similar to JS in being nearly all old-growth forest. PC has 1760 ha of forest with trees >90 m (the largest single area remaining), which also contains several of the largest known individual trees (Van Pelt, 2001;Sillett et al., 2015a). Both JS and PC's proximity to the coast makes them exposed to winter storms that damage tree crowns, but subsequent growth and recovery of Sequoia creates some of the largest and most complex tree crowns Sillett et al., 2015a). ...
... Primary forests in the wet tropics have continuous forest cover spanning generations of trees, such that the oldest living dominants established under forest conditions (Leigh et al., 1982;Brokaw, 1985;Oldeman, 1990;Clark and Clark, 1992). Developmentally similar temperate forests are dominated by Cupressaceae in wet coastal mountains around the Pacific Rim. Chamaecyparis, Cryptomeria, Cupressus, Fitzroya, Sequoia, Taiwania, and Thuja can all live >1500 years (Carder, 1995;Van Pelt, 2001;Farjon, 2005Farjon, , 2008Earle, 2015;Sillett et al., 2015a). Even with trees so old, the forests in which they grow may be much older because shade-tolerant individuals attain canopy dominant positions in the absence of stand-replacing disturbances (Fritz, 1957;Veblen and Ashton, 1982;Kojo, 1987;Franklin et al., 1988;Enright and Hill, 1996;Farjon, 2005;Van Pelt, 2007;Lorimer et al., 2009). ...
Forests >80 m tall have the highest biomass, and individual trees in these forests are Earth’s largest with deep crowns emerging above neighboring vegetation, but it is unclear to what degree these maxima depend on the emergent trees themselves or a broader-scale forest structure. Here we advance the concept of _emergent facilitation_, whereby emergent trees benefit co-occurring species. Trees reorganize foliage within crowns to optimize available light and, if long-lived, can reiterate after crown damage to become emergent. The height, depth, and spacing of emergent trees in turn allows for abundant light to pass through the canopy, leading to light-use complementarity as well as elevated biomass, leaf area, and species diversity of the forest as a whole. We chose _Sequoia sempervirens_ to develop this concept and installed eleven 1-ha plots in old-growth forests spanning nearly six degrees of latitude in California. Each plot was based off a 316-m-long centerline where biomass and leaf area of all vegetation were quantified. We employed hierarchical measurements and stratified random sampling spanning the full size range of individuals to generate 180 equations for determining biomass and leaf area of all dominant plant species in these forests. Biomass (5190 Mg ha−1), leaf area (LAI = 19.4), and aboveground carbon (2600 Mg ha−1) are global maxima, occurring in plots with the highest proportion of emergent trees. Decay-resistant _Sequoia_ heartwood contributes the bulk of this mass, ranging from 61.5 to 76.7% of plot totals. Heartwood is a key contributor to the development of trees with emergent crowns, since its durability enables trees to recover leaf area and to re-grow crowns after damage so that they can continue expanding for millennia. By distributing leaf area among fewer trees with deeper crowns, _Sequoia_ maintains very high leaf area itself (LAI up to 14.5) while simultaneously allowing other species to flourish underneath (non-_Sequoia_ LAI up to 8.0). Because _Sequoia_ is not replaced by other species, aboveground biomass, leaf area, and carbon content of these forests are essentially asymptotic over time.
... In addition to epicormic branches, old trees often possess reiterated trunks that can resemble young trees arising from the main trunk, other trunks, or limbs (see Appendix A for definitions of limb and 20 other treestructure terms). Very large Pseudotsuga trees often have dozens of reiterated trunks in crowns occupying several thousand cubic meters of canopy volume (Van Pelt 2001). Throughout their lifetimes, diseases and physical injuries from wind, fire, and animals also predispose trees to infections by wood decay fungi, which form expanding colonies in their roots, trunks, limbs, and branches, ultimately limiting longevity. ...
... Patterns of growth, mortality, epicormic shoot production, trunk reiteration, and wood decay clearly contribute to the development of individuality and structural complexity in forest trees, but the progression of this transformation has not been adequately described. Whole trees can be difficult to study, particularly for a species capable of reaching the dimensions of Pseudotsuga: living trees up to 5.7 m in diameter and 99 m tall still exist (Van Pelt 2001). In the early 1970s at the H. J. Andrews Experimental Forest in Oregon, nine Pseudotsuga trees from an old-growth forest were climbed and crown-mapped to quantify leaf biomass, bark surface area, and epiphytes. ...
... While site quality varied between the seven stands (Table 1), our plots represented the full range of structural development within the coastal form of Pseudotsuga. A review of both popular and scientific literature (Waring and Franklin 1979, Stoltmann 1996, Van Pelt 2001, Cissel and Cissel 2003), discussions with knowledgeable foresters and ecologists (J. Agee, J. Cissel, J. Franklin, J. Henderson, T. Hinckley, D. Shaw, T. Spies), and extensive reconnaissance within the range of Pseudotsuga allowed us to conclude that our ''end point'' of structural complexity was indeed at or near the maximum attained by the species. ...
Seventy trees from seven stands 50-650 years old were selected for this investigation of crown structural development in Pseudotsuga menziesuii All branches, limbs, and trunks were nondestructively measured for size, structure, and location while climbing the trees with ropes. These data were used to generate a computer model of each tree's crown that was error-checked trigonometrically. Leaves, bark, cambium, and wood were quantified by using limited destructive sampling to develop predictive equations that were applied to the complete inventory of structures in each tree's crown. Summations of these values yielded whole-tree estimates of several structural variables. A second set of equations was then developed to predict these whole-tree parameters from simple, ground-based measurements. Principal components analysis of 24 tree-level variables revealed two orthogonal dimensions of structure that accounted for 71.3% and 12.4% of total variation in the 70 trees. The first dimension represented a gradient of overall tree size and structural complexity that was positively correlated with tree age (R2 = 0.89). The second dimension represented a gradient of incremental growth potential that was positively correlated with measured growth of main trunks at breast height during the five-year period after trees were mapped (R2 = 0.39). The strongest determinant of incremental growth potential was the ratio of a tree's total cambium surface area to projected leaf area. A tree's incremental growth potential may thus be unrelated to either size or structural complexity and depend instead on factors related to whole-tree carbon balance (e.g., how much the tree invests in fighting and feeding fungi). Our intensive analyses of Pseudotsuga menziesii and extensive observations of other species were used to develop a conceptual model of crown development in tall conifers. Trees respond to disturbances by growth of replacement structures whose form depends on disturbance intensity and age. Young trees rebuild damaged crowns through epicormic shoot production on original branches, whereas older trees also recover by producing new, epicormic branches. Damage to main trunks and top dieback stimulate production of reiterated trunks. Repeated damage leads to multiple hierarchical levels of trunk reiteration as well as to limb formation and increasing tree individuality.
... Picea sitchensis is an ideal species with which to demonstrate this methodology because it is a dominant structural element in many coastal forests (Franklin and Dyrness, 1988;Van Pelt et al., 2006) and no published allometrics yet span its full size range up to > 90 m tall and > 400 cm diameter (Chin and Sillett, 2017;Van Pelt, 2001). Native to the northwest coast of North America from Alaska to California, P. sitchensis grows in forest receiving over 500 to under 65 cm of annual rainfall (Burns and Honkala, 1990). ...
... Dataset 4 was included as an anchor for the large end of the equations by including five very large trees. It included the three largest known before they toppled or started collapsing from decay and two other partially mapped trees (Van Pelt, 2001). All trees were either climbed and trunk mapped, or the trunk was measured from the ground using a reticle on the lens of a scope to capture diameter at multiple heights aboveground. ...
Tree biomass is one of the most important variables for studying and managing forest ecosystems. With emphasis shifting from young forests grown for timber production to forests with old-growth characteristics, the need to quantify various components of individual trees in natural settings is increasing. Destructive methods are inherently limited by what is feasible to cut down, dissect, and measure. In contrast, crown mapping is a minimally invasive technique for quantifying aboveground tree components such as wood, cambium, bark, and leaves. Despite being applied mostly to large trees, it is generalizable to any woody plant and can be adapted to answer diverse questions about biology, ecology, and ecosystem functions. We present a generalized approach for non-destructively quantifying the three-dimensional structure and aboveground components of whole trees along with a new programmatic tool for error-checking, visualizing, and interacting with tree-level data. Crown-mapping data from 60 lowland rainforest Picea sitchensis trees are presented to demonstrate the utility of this method for deriving allometric equations of tree components based on ground measurements. The 60 trees range from 14 to 495 cm trunk diameter at breast height, 10 to 94 m tall, and include simple to structurally complex individuals in dominant to suppressed positions within forests varying widely in density. Final allometric equations explain > 90% of the variability in volumes and masses of bark, wood, and leaves; are applicable to P. sitchensis throughout much of its geographic range; and are conservative relative to equations based on smaller dissected trees. Dendrochronology and allometric equations demonstrate that Picea sitchensis radically out-paces both Pseudotsuga menziesii and Sequoia sempervirens in accumulation of aboveground biomass and leaves, becoming heavier (155 ± 9 Mg) than any living P. menziesii and almost half as heavy as any living S. sempervirens in < 500 years.
... In many cases, the diameter ranges of trees used to develop an equation did not extend throughout the diameter range of trees in our dataset. Yosemite and Sequoia contain the largest (or nearly so) individuals of Pinus ponderosa, Pinus lambertiana, Abies concolor, Abies magnifica, and Sequoiadendron giganteum [51], and because destructive sampling is generally enjoined in the parks, allometric equations extending to those large diameters do not exist. For large-diameter trees, we created blended equations using species-specific equations over the diameter range of trees from which the equation was developed and equations from similar species and growth forms that covered the necessary extended diameter range. ...
... Yosemite and Sequoia & Kings Canyon National Parks contain some of the largest individuals of Abies magnifica, Abies concolor, Pinus lambertiana, and Pinus jeffreyi [51] in addition to the largest individuals of Sequoiadendron giganteum. The biomass of these individuals is considerable (with densities of such trees generally 1 ha −1 to 3 ha −1 ), but no allometric equations extend to the diameters of the largest trees found in the monitoring plots or the surrounding forests. ...
Fire is one of the principal agents changing forest carbon stocks and landscape level distributions of carbon, but few studies have addressed how accurate carbon accounting of fire-killed trees is or can be. We used a large number of forested plots (1646), detailed selection of species-specific and location-specific allometric equations, vegetation type maps with high levels of accuracy, and Monte Carlo simulation to model the amount and uncertainty of aboveground tree carbon present in tree species (hereafter, carbon) within. Low-severity and moderate-severity fire had little or no effect on the amount of carbon sequestered in trees at the landscape scale, and high-severity fire did not immediately consume much carbon. Although many of our data inputs were more accurate than those used in similar studies in other locations, the total uncertainty of carbon estimates was still greater than ±10%, mostly due to potential uncertainties in landscape-scale vegetation type mismatches and trees larger than the ranges of existing allometric equations. If carbon inventories are to be meaningfully used in policy, there is an urgent need for more accurate landscape classification methods, improvement in allometric equations for tree species, and better understanding of the uncertainties inherent in existing carbon accounting methods.
... The largest floods in all three hydrologic regimes occur during powerful fall and winter storms when rain falls on snow. The PCE floodplains support high regional biodiversity and historically productive salmon (Oncorhynchus spp.) populations, yield abundant clean water, and are well known for large and rapidly growing endemic trees (Waring and Franklin 1979; Van Pelt 2001; Naiman and others 2005b). In general, the valley bottoms are dominated by mixed communities of willow (Salix sp.), red alder (Alnus rubra), black cottonwood (Populus balsamifera trichocarpa), bigleaf maple (Acer macrophyllum), Sitka spruce (Picea sitchensis), Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla ), western redcedar (Thuja plicata) and, in the southern-most regions, coast redwood (Sequoia sempervirens; Franklin and Dyrness 1973). ...
... Collectively, the physiologies of individual species, as well as the nutrients and OM from soil processes and from the ocean and from canopy epiphytes, contribute synergistically to tree production. Even though older PCE floodplain forests are patchy, they contain some of the fastest-growing and tallest trees known (Van Pelt 2001 ). Unlike other temperate or tropical alluvial forests, the long-lived conifer forests of the PCE maintain high productivity into the second and even third centuries of forest succession, accumulating impressive biomass (Table 2). ...
Floodplains in the Pacific Coastal Ecoregion (PCE) stem from steep eroding mountain landscapes in a rain forest environment,
and sustain a rich array of natural resources. Like floodplains elsewhere, many of the approximately 200 coastal river valleys
are profoundly altered by flow regulation and land conversion for agriculture and urban development, and these activities
have contributed to widespread declines in anadromous fishes and environmental quality. Some of the coastal river valleys,
however, still retain many of their natural features, thereby providing important reference sites. Understanding fundamental
biophysical processes underpinning natural floodplain characteristics is essential for successfully protecting and restoring
ecological integrity, including inherent goods and services. This article examines factors underpinning the ecological characteristics
of PCE floodplains, particularly riparian soils and trees. Drawing on over two decades of research and literature, we describe
the spatial and temporal characteristics of physical features for alluvial PCE floodplains, examine the importance of sediment
deposition and associated biogeochemical processes in floodplain soil formation, quantify vegetative succession and production
dynamics of riparian trees, discuss how epiphytes, marine-derived nutrients, and soil processes contribute to tree production,
describe the roles and importance of large dead wood in the system, the role of termites in its rapid decomposition, and show
how large wood contributes to vegetative succession. These highly interconnected features and associated processes are summarized
in a model of system-scale drivers and changes occurring over several centuries. Collectively, this integrated perspective
has strong implications for floodplain rehabilitation, and we identify appropriate metrics for evaluating floodplain condition
and functions. We draw heavily from our own experience on several well-studied rivers, recognizing additional studies are
needed to evaluate the generality of concepts presented herein. As in any complex adaptive system, fundamental uncertainties
remain and constraints imposed by the legacies of past human actions persist. Nevertheless, the evolving knowledge base is
improving conservation strategies of lightly modified floodplains and is supporting the incorporation of emerging process-based
perspectives into the rehabilitation of heavily modified systems.
... Indeed, vascular epiphytes are abundant only in old-growth redwood forests within 10 km of the ocean. These rain forests contain some of the largest and most structurally complex redwoods (Van Pelt, 2001) as well as the tallest known Picea sitchensis (Bong.) Carr. ...
... Epiphyte richness is the total number of vascular plant species occurring as epiphytes on each tree. Asterisks next to tree names indicate members of the top ten largest known living redwoods(Van Pelt, 2001). ...
Redwood forests contain some of the largest and most structurally complex trees on Earth. The most abundant vascular epiphyte in these forests is the fern Polypodium scouleri (Polypodiaceae). We measured dimensions of all 765 P. scouleri mats on 32 trees (27 Sequoia sempervirens, 5 Picea sitchensis). Eighteen P. scouleri mats from 11 trees were randomly selected for removal and dissection in the laboratory. The total fern mat mass consisted of live fronds (3.3%), dead fronds (2.4%), live rhizomes (4.2%), dead rhizomes (8.9%), roots (34.4%), humus (28.0%), and debris (18.8%). We used multiple regression analysis to develop equations for estimation of fern masses, and we applied these equations to undisturbed fern mats on the 32 trees. Individual trees supported up to 742 kg dry mass of P. scouleri mats. These are the highest whole-tree epiphyte masses ever reported. We also quantified crown structure and counted the number of vascular plant species occurring as epiphytes on each tree. Very large, complex trees had more fern mat mass and higher vascular epiphyte species richness than smaller, simpler trees. Desiccation-sensitive organisms dependent on water stored in fern mats may be unable to survive in managed redwood forests lacking large, complex trees with abundant P. scouleri.
... Additionally, the qPipe model provides over/underestimations due to other factors. For example, many long-lived 'giant' trees 38,39 are known to undergo treetop breakage because of natural phenomena such as lightning strikes and strong winds. Such trees are expected to have a less tapered, cylindrical stem (i.e., X > 2 in Eq. (3)) owing to the loss of their top part and would have a much higher H value if breakage had not occurred. ...
The allometry of the pipe model quantifies the approximate proportionality between the tree leaf amount and the stem cross-sectional area at the crown base (ACB). It is useful for estimating and modeling carbon fixation abilities of trees but requires climbing the tree and is thus unsuitable for large-scale studies. Here, we adopted a previously proposed allometry (hereafter the quasi-pipe (qPipe) model allometry) formulating the relationship between the tree leaf amount and a surrogate of ACB, ACB_Est, calculated from tree dimensions measurable from the ground. Using published/unpublished data for 962 trees of 159 species collected between tropical rainforests and boreal forests, we established pipe and qPipe model allometries for evergreen-conifer, deciduous-conifer, evergreen-broadleaf, and deciduous-broadleaf plant functional types (PFTs). For the leaf area per tree (LA), allometric lines on a log–log plane were almost identical among the four PFTs in both models, with slopes of ~ 1. For the leaf mass per tree (LM), however, the allometric lines separated among the four PFTs in both models and had slopes greater than 1, indicating that the proportionality assumed in the pipe model held for LA but not LM. The applicability of the qPipe model in estimating the stand-scale leaf amount was further examined.
... While the lower watershed has undergone significant impacts from forest harvest, the upper watershed is part of the Olympic National Park (ONP) where forest harvest is prohibited. The trees of the old-growth forest in the ONP can be up to 80 m in height (Harmon and Franklin, 1989) while the lower watershed is dominated plantation forests managed for timber harvest (Pelt, 2001). The wetlands within the Hoh watershed are diverse, from precipitation-driven 155 peat bogs to riparian wetlands driven by stream flow inputs as well as wetlands driven by surface water flows and groundwater inputs. ...
Accurate, un-biased wetland inventories are critical to monitor and protect wetlands from future harm or land conversion. However, most wetland inventories are constructed through manual image interpretation or automated classification of multi-band imagery and are biased towards wetlands that are easy to detect directly in aerial and satellite imagery. Wetlands that are obscured by forest canopy, occur ephemerally, and those without visible standing water are, therefore, often missing from wetland maps. To aid in detection of these cryptic wetlands, we developed the Wetland Intrinsic Potential tool, based on a wetland indicator framework commonly used on the ground to detect wetlands through the presence of hydrophytic vegetation, hydrology, and hydric soils. Our tool uses a random forest model with spatially explicit input variables that represent all three wetland indicators, including novel multi-scale topographic indicators that represent the processes that drive wetland formation, to derive a map of wetland probability. With the ability to include multi-scale topographic indicators, the WIP tool can identify areas conducive to wetland formation and provides a flexible approach that can be adapted to diverse landscapes. For a study area in the Hoh River Basin in Western Washington, USA, classification of the output probability with a threshold of 0.5 provided an overall accuracy of 91.97 %. Compared to the National Wetland Inventory, the classified WIP-tool output increased areas classified as wetland by 160 % and reduced errors of omission from 47.5 % to 14.1 %, but increased errors of commission from 1.9 % to 10.5 %. The WIP tool is implemented using a combination of R and python scripts in ArcGIS.
... While Lenihan et al. (2008) projected an expansion of hardwoods, including black oak, in California's mixed evergreen forests by the 2080s, others have found recent declines specifically in large-diameter black oak from fire [ Long et al. (2018), in longer-term analysis of FIA data]. Around the 1700s AD in the Sierra Nevada, which overlaps much of black oak's current range, there was a period of dry, cool temperatures that was predated and followed by a wetter and warmer period (Stine, 1996;Van Pelt, 2001;Lutz et al., 2010). Many of the tree species that established during this time, including mature black oak and coastal Douglasfir, may be at higher risk of mortality if they are located toward the fringe of the species current range (Lutz et al., 2010). ...
Rapid climate change over the coming century will impact suitable habitat for many tree species. In response to these changes in climate, areas that become unsuitable will see higher mortality and lower growth and recruitment. Therefore, early detection of demographic trends is critical for effective forest management. Recent 10-year remeasurement data from the United States (US) Department of Agriculture (USDA) Forest Service’s Forest Inventory and Analysis (FIA) Program’s national annual inventory of forest land provides an ideal data set for analyzing such trends over large areas. However, failure to distinguish between areas of future habitat contraction and expansion or persistence when estimating demographic trends may mask species’ shifts. We used remeasurement data to compare observed tree demographic rates with projected impacts of climate change for five important tree species in the Pacific Northwest. Projected impacts were based on spatial-Bayesian hierarchical models of species distributions, which were used to project areas where habitat would persist (remain climatically suitable), expand (become suitable), or contract (become unsuitable) under four future climate scenarios for the 2080s. We compared estimates of mortality and net-growth between these areas of shifting suitability and a naïve division of habitat based on elevation and latitude. Within these regions, we assessed the sustainability of mortality and determined that observational data suggest that climate change impacts were already being felt in some areas by some species. While there is an extensive literature on bioclimatic species distribution models, this work demonstrates they can be adapted to the practical problem of detecting early climate-related trends using national forest inventory data. Of the species examined, California black oak ( Quercus kelloggii ) had the most notable instances of observed data suggesting population declines in the core of its current range.
... Trees are culturally and spiritually important in many societies (Omura, 2004;Hall et al., 2011). Individuals and organizations maintain large tree registries (Van Pelt, 2001) and government agencies maintain parks and reserves dedicated to the sustainability of exceptionally large trees (James et al., 2012). There are several pests affecting the growth and development of trees, it varies from fungal, bacterial, nematode pest infections and at times severe insect damages (Khan, 2012). ...
Plant-parasitic nematodes contribute to unnoticeable damages which lead to gradual decline in the values and eventually death of amenity trees. Identification of these nematode pests is vital for their effective management. Reconnaissance survey was carried out to identify amenity tree species present in the University of Port Harcourt (UNIPORT). Composite bulked soil and root samples (126) were collected from amenity trees in UNIPORT and nematode pests were extracted from samples using modified Baerman method. The nematode pests were identified and their populations determined using standard procedures. Relative importance value (RIV) and diversity indices were calculated with appropriate software. Data were processed using descriptive statistics and with analysis of variance. 38 tree species were identified in UNIPORT belonging to 20 families. Terminalia mantaly, Cocos nucifera and Terminalia catappa with RIVs of 15.1, 9.35, and 9.12 respectively were the three most important amenity trees in UNIPORT. Fifteen nematode pest genera; Helicotylenchus, Aporcelaimus, Tylenchulus, Meloidogyne, Scutelonema, Pratylenchus, Tylenchus, Rotylenchoides, Criconema, Hemicyliophora, Trichodorus, Mesodorylaimus, Heterodera, Paratylenchus and Longidorus were associated with 21 of the amenity trees. The three most important nematode pest genera were Helicotylenchus, Tylenchulus and Aporcelaimus with RIVs of 42%, 16% and 5.34%, respectively. Helicotylenchus (RIV 45.41%) and Tylenchulus (RIV 30%) were the most important plant-parasitic nematode genera in the soil and roots of amenity trees, respectively. Helicotylenchus, Tylenchulus and Aporcelaimus were the three most important plant-parasitic nematode genera associated with amenity trees in UNIPORT. Keywords: Amenity trees, Diversity indices, Identification, Nematode pests, Survey
... But it is an approach that is conceptually different from volume and biomass models, with specific fitting problems (Fang & Bailey, 1999;Parresol, 1999), and is outside the scope of this guide. It should be noted that when dealing with very large trees, for which it is almost impossible to measure biomass directly, the stem profile approach is a relevant alternative (Van Pelt, 2001;Dean et al., 2003;Dean, 2003;Dean & Roxburgh, 2006;Sillett et al., 2010). ...
... One of the study trees (Terex Titan) revealed the full spectrum of epiphyte succession, including a climactic stage dominated by woody epiphytes. Thirty-four reiterated trunks to 148 cm diameter emerged from middle and lower crown strata (see Van Pelt 2001). These trunks and their branches harbored lichens and bryophytes in the typical spatial sequence, while the gnarly main section of the tree between 35 and 65 m above the ground consisted of huge, broken trunks and thick, shearedoff limbs that carried abundant soil, decaying wood and eight species of vascular plants. ...
We used rope techniques to access epiphyte communities on nine large and structurally complex redwoods (Sequoia sempervirens) occupying old-growth forest reserves of northwestern California. All species of epiphytic lichens, bryophytes and vascular plants were recorded, biomass of dominant vascular epiphytes (Polypodium scouleri and Vaccinium ovatum) was quantified, and tree crowns were mapped to estimate substrate surface areas. We employed a flexible, plot-based sampling regime defined by available microhabitats within height strata to search for epiphytes. All substrates were examined, including tree surfaces, canopy soils and perennially exposed surfaces of epiphytic vascular plants as well as forest floor vegetation, woody debris and terrestrial soils beneath the redwood crowns. Combined arboreal and terrestrial search efforts revealed 282 species, including 183 lichens, 50 bryophytes and 49 vascular plants. Beta diversities for plots aggregated by floristic group, stratum and substrate type were generally high, indicating a large proportion of infrequent species. Indirect ordination analysis suggested that an environmental gradient from exposed to sheltered habitats was the strongest factor controlling epiphyte community structure. Floristic groups, strata and substrates were highly segregated along the dominant compositional gradient. Chlorolichens, upper crown strata and redwood foliage occupied one end, while vascular plants, forest floor strata and terrestrial woody debris occupied the other end of the gradient. Indicator Species Analyses revealed that many species expressed affinities for particular substrates, including live vs. dead foliage, bark of small vs. large branches and limbs, bark of upper vs. lower surfaces of large limbs, bark of large trunks, bare wood, bryophyte mats, soils, non-redwood stems and terrestrial woody debris. Cluster Analysis identified seven groups of species with similar patterns of distribution across height strata and substrate types. Correlations between tree structure and species distribution suggested that structural complexity promoted epiphyte diversity within height strata. Surface areas of small live trunks, limbs and dead trunks were the best predictors of lichen species richness, Polypodium scouleri biomass and Vaccinium ovatum biomass, respectively. At least one new species (Calicium sp. nov.) was discovered, and two species (Buxbaumia piperi, Icmadophila ericetorum) normally restricted to terrestrial habitats were found as canopy epiphytes for the first time.
... Although the tallest conifers have similar patterns of crown development-increasing structural complexity as original tops and branches are damaged and replaced-S. sempervirens is far more fire-and decay-resistant and longer-lived than P. sitchensis, while P. menziesii is intermediate in these characteristics (Van Pelt, 2001;Van Pelt and Sillett, 2008;Sillett et al., 2018). Whereas S. sempervirens has leaves that respond anatomically to the within-crown water-stress gradient, leaf development of P. sitchensis is primarily controlled by light availability (Oldham et al., 2010;Chin and Sillett, 2017). ...
PREMISE OF THE STUDY: Leaves are the sites of greatest water stress in trees and a key means
of acclimation to the environment. We considered phenotypic plasticity of Pseudotsuga
menziesii leaves in their ecological context, exploring responsiveness to natural gradients
in water stress (indicated by sample height) and light availability (measured from
hemispherical photos) to understand how leaf structure is controlled by abiotic factors in
tall tree crowns.
METHODS: After measuring anatomy, morphology, and carbon isotope composition (δ13C)
of leaves throughout crowns of P. menziesii >90 m tall, we compared structural plasticity
of leaves among the three tallest conifer species using equivalent data from past work on
Sequoia sempervirens and Picea sitchensis.
KEY RESULTS: Leaf mass per projected area (LMA) and δ13C increased and mesoporosity
(airspace/area) decreased along the water-stress
gradient, while light did not play
a detectable role in leaf development. Overall, leaves of P. menziesii were far less
phenotypically responsive to within-crown
abiotic gradients than either P. sitchensis, whose
leaves responded strongly to light availability, or S. sempervirens, whose leaves responded
equally strongly to water stress.
CONCLUSIONS: P. menziesii maintain remarkably consistent leaf structure despite
pronounced vertical gradients in abiotic factors. Contrasting patterns of leaf structural
plasticity underlie divergent ecological strategies of the three tallest conifer species, which
coexist in Californian rainforests.
... Western white pine, the dominant species at Emerald Lake, is locally abundant in subalpine habitats along the western slope of the Sierra Nevada, where it may occur in small pure stands but more commonly is found mixed with lodgepole pine, Jeffrey pine, mountain hemlock, and red fir (Potter 1998). Although trees of this species may reach 40 m in height and 2.5 m in diameter in the Sierra Nevada, these sizes are smaller than those reached by western white pines in the northern Rocky Mountains and Pacific Northwest (Van Pelt 2001). Western white pine generally maintains a tree form of growth up nearly to treeline, where it is commonly replaced in the Sierra Nevada by whitebark pine or foxtail pine on rocky ridges (Millar and Rundel 2016). ...
The Emerald Lake watershed forms a subalpine basin in the upper drainage of the Marble Fork of the Kaweah River in Sequoia National Park, California, with elevations ranging from 2804–3416 m. Five conifer species are present in the basin, with western white pine (Pinus monticola Douglas ex D. Don) as the most dominant species forming 71% of the stems and 82% of basal area censused in 1985 and 1986. Lodgepole pine (Pinus contorta Loudon subsp. murrayana (Grev. & Balf.) Critchf.) was the second most dominant in the watershed as measured by numbers of individuals and basal area, but was almost entirely restricted to mesic bench and wet meadow habitats in the lower elevations of the watershed. Foxtail pine (Pinus balfouriana Grev. & Balf.) comprised 9.5% of the stems and 13.7% of the basal area within the basin, but was largely present on higher north-facing ridgelines where it formed 52% of stems and 65% of basal area. Jeffrey pine (Pinus jeffreyi Grev. & Balf.), and red fir (Abies magnifica A. Murray bis var. critchfieldii Lanner) were present in small numbers in the lower basin in wet meadow and/or mesic granite bench habitats.
... Trees at all five sites ranged from 35.7 to 89.9 m height and 111-598 cm diameter at the top of the buttress (i.e., the lowest point at which the trunk becomes nearly round). No accurate age estimates are available for the trees at the "L2L" sites but the oldest individuals likely exceed 3000 years (Van Pelt, 2001). ...
Drought is expected to become an increasingly important stressor on forests globally, and understanding the physiological mechanisms driving tree drought response is essential for developing effective mitigation and conservation measures for these ecosystems. In 2014, during California's 2012-2016 "hotter" drought in which higher temperatures exacerbated the effects of low water availability, many giant sequoia trees in the Sierra Nevada mountains exhibited foliage dieback at levels previously unreported. We hypothesized that this apparent drought-induced foliage dieback was associated with spatial patterns of site water balance and consequently tree water status and physiology. As part of an ongoing collaborative project aimed at understanding and mapping giant sequoia drought response and vulnerability at leaf to landscape scales, in 2015, 2016 and 2017 we climbed and measured leaf-level water status and physiology of mature and seedling giant sequoia trees at sites exhibiting low and high average foliage dieback in Giant Forest, Sequoia National Park. We also compared our 2015-2017 measurements with similar measurements made in giant sequoias prior to the commencement of the 2012-2016 drought. We found that during the drought, leaf water potentials of both mature and seedling sequoias were as low or lower than any previous measurements, and leaf water potentials of some seedlings were as low as the tops of mature trees. In contrast to our expectations, we found similar water potentials in both foliage dieback classes, although there was a high degree of within-site variability and in some measurement periods trees and seedlings growing in flat or meadow-side topographic positions had higher water potentials than those growing on mid- or upslope positions with presumably less favorable water supply. Leaf-level adjustments included multiple mechanisms to reduce water loss and resist the effects of desiccation at both seasonal and annual time scales, including stomatal closure, redistribution of leaf water to less mobile storage, and a shift in leaf carbon fractions to build tougher, more drought-resistant foliage. Our results suggest that giant sequoia employs a drought avoidance water regulation strategy and leaf-level adjustments are sufficient to maintain relatively isohydric water potentials above critical thresholds under most conditions. Because of the high severity of the 2012-2016 drought, however, the capacity for leaf-level compensation in some giant sequoias was overwhelmed and both leaf- and crown-level adjustments were necessary to maintain favorable water status to protect whole-tree hydraulic functioning. Additional research aimed at understanding and monitoring the consequences of future hotter droughts is necessary in order to determine the long-term persistence of giant sequoias within their current geographic distribution.
... Coast redwood (Sequoia sempervirens) forests are an important component of California's ecosystems. Spanning more than six degrees of latitude along the Pacific coast (Van Pelt 2001) and containing individual trees that can live for more than 2000 years (Rocky Mountain Tree Ring Research 2017), these forests provide important habitats for many terrestrial species (Sawyer et al. 1999). However, biodiversity occupying the redwood forest canopies remains relatively under-explored because access into the tree crowns, which often grow to over 100 m in height, is challenging. ...
Xylopsora canopeorum
Timdal, Reese Næsborg & Bendiksby is described as a new species occupying the crowns of largeSequoia sempervirenstrees in California, USA. The new species is supported by morphology, anatomy, secondary chemistry and DNA sequence data. While similar in external appearance toX. friesii, it is distinguished by forming smaller, partly coralloid squamules, by the occurrence of soralia and, in some specimens, by the presence of thamnolic acid in addition to friesiic acid in the thallus. Molecular phylogenetic results are based on nuclear (ITS and LSU) as well as mitochondrial (SSU) ribosomal DNA sequence alignments. Phylogenetic hypotheses obtained using Bayesian Inference, Maximum Likelihood and Maximum Parsimony all supportX. canopeorumas a distinct evolutionary lineage belonging to theX. caradocensis-X. friesiiclade.
... In Alaska, mature trees near sea level often exceed 61 m in height and 3 m in diameter [54,55]. Stands with Sitka spruce as a major component tend to be dense, with high yields and large tree size [32,[56][57][58][59]. ...
There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well-planned silvicultural systems containing a mixture of broadleaf-conifer species have potential to enhance stand diversity and provide other ecosystem services earlier than typical even-aged conifer plantations. Here, we use the example of mixed Sitka spruce/western hemlock and red alder in young, managed stands in southeast Alaska to achieve these goals. We briefly describe the silvics of Sitka spruce, western hemlock and red alder plantations as pure conifer stands or pure broadleaf stands. Then, we synthesize studies of mixed red alder-Sitka spruce/western hemlock stands in southeast Alaska and present their potential for improving stand structural complexity, biodiversity and other ecosystem services over pure conifer forests. Finally, we discuss some of the opportunities and potential tradeoffs for managing mixed broadleaf-conifer stands for providing a number of natural resources and the influence of these broadleaf-conifer forests on ecosystem linkages and processes.
... In Alaska, mature trees near sea level often exceed 61 m in height and 3 m in diameter [54,55]. Stands with Sitka spruce as a major component tend to be dense, with high yields and large tree size [32,[56][57][58][59]. ...
There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long‐term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well‐planned silvicultural systems containing a mixture of broadleaf–conifer species have potential to enhance stand diversity and provide other ecosystem services earlier than typical evenaged conifer plantations. Here, we use the example of mixed Sitka spruce/western hemlock and red alder in young, managed stands in southeast Alaska to achieve these goals. We briefly describe the silvics of Sitka spruce, western hemlock and red alder plantations as pure conifer stands or pure broadleaf stands. Then, we synthesize studies of mixed red alder‐Sitka spruce/western hemlock stands in southeast Alaska and present their potential for improving stand structural complexity, biodiversity and other ecosystem services over pure conifer forests. Finally, we discuss some of the opportunities and potential tradeoffs for managing mixed broadleaf–conifer stands for providing a number of natural resources and the influence of these broadleaf–conifer forests on ecosystem linkages and processes.
... North!America!that!is!distributed!from!northern!Oregon!to!Baja!California!at!a!wide! span!of!altitudes.!It!is!currently!the!tallest!pine!species!with!heights!reaching!76! meters.!The!female!cones!of!sugar!pine!are!also!gigantic,!often!longer!than!600!cm! (Kinloch!and!Scheuner!1990;!Van!Pelt!2001;!American!Forests!2015).!P.&lambertiana! trees!may!live!longer!than!500!years!and!the!onset!of!the!species'!sexual! reproduction!is!delayed!compared!to!other!pines,!possibly!due!to!the!height!and! girth!needed!to!support!these!massive!strobili.!Paralleling!these!oversized! ...
Until very recently, complete characterization of the megagenomes of conifers has remained elusive. The diploid genome of sugar pine (Pinus lambertiana Dougl.) has a highly repetitive 31 billion base pair genome. With nearly 50% more DNA than the current record holder, Pinus taeda, sugar pine is the largest genome sequenced to date. This genome is the first to be sequenced from the subgenus Strobus, or white pines, a group that is notable for having the largest genomes among the pines. The genome represents a unique opportunity to investigate genome "obesity" in conifers and white pines. The crux of our sequencing approach has been to leverage aspects of conifer biology to reduce the complexity of the assembly problem. Comparative analysis of P. lambertiana and P. taeda reveals new insights on the conservation, age, and diversity of the highly abundant transposable elements, the primary factor determining genome size. Like most North American white pines the principal pathogen of P. lambertiana is white pine blister rust (Cronartium ribicola J.C. Fischer ex Raben.). Identification of the candidate genes for resistance to this pathogen is great ecological importance. The genome afforded us the opportunity to make substantial progress on locating the major dominant gene for simple resistance hypersensitive response, Cr1 We describe new markers and gene annotation that are both tightly linked to Cr1 in a mapping population and associated to Cr1 in unrelated individuals sampled throughout the range, creating a solid foundation for future mapping. This genomic variation and annotated candidate genes characterized in our study of Cr1 region are resources for future marker-assisted breeding efforts as well as investigations of fundamental mechanisms of invasive disease and evolutionary response.
... In other cases, multiple reiterated trunks arise and compete with each other. The crowns of tall, old conifers often contain dozens of reiterated trunks emerging from the main trunk, other trunks, and limbs , Van Pelt 2001R. Van Pelt and S. C. Sillett, unpublished manuscript). ...
... Some more modest dimensions has been observed in the forests of the highlands: 10 -135cm in the Kouoghap sacred submontane forest, 10-120cm in the Manengouba montane forest (Noumi, 2012 and, in the Messa submontane forest (Tagne, 2007) the big diameters are between 200 and 230cm. The trees with diameters equal or superior to those of the Oku sacred forest are observed in the temperate countries; 6 to 8m for Sequoiadendron giganteum (Lindley) J. Buchholz, 1939 (Cupressaceae) (Fig. 12C); the most imposing specimen is 'General Sherman', in the national Park of Redwood (United States) (Robert, 2001) ; 2 to 3m for Pseudotsuga menziesii (Mirb.) Free, 1950 (Pinaceae) (Mailleux et al., 2007); 2m for Abies nordmanniana (Steven) Spach, 1841 (Pinaceae) (Julve, 1998). ...
... A large part of this area is covered by old-growth coniferous forests, dominated primary by Douglas fir, Western hemlock and Western red-cedar (Tsuga heterophylla zone). The mentioned forests belong to the tallest, densest and most productive woods in the world and very important both from ecological and economical point of view ( Franklin & Dyreness 1988, Van Pelt 2001). The cosmopolitan genus Friesea Dalla Torre, 1895 is the largest in the entire family Neanuridae and currently comprises about 170 taxa, recognized as species or subspecies ( Palacios-Vargas 2005). ...
Two new species of genera Friesea Dalla Torre, 1895 and Stachia Folsom, 1932 are described and fully illustrated. Friesea kariae sp. nov. is easily distinguished by absence of eyes, presence of five anal spines, furcula in state 3 and retinaculum with 2+2 teeth. Stachia oregonensis sp. nov. is easily distinguished by its femoral and trochanteral chaetotaxy, presence of three rounded lobes in postantennal organ and setae a 1 on most thoracic and abdominal terga. Keys to the known eyeless members of the genus Friesea Dalla Torre, 1895 and all the species of Stachia Folsom, 1932 are also included.
... Así también se pueden mencionar las celebraciones del día del árbol o las diferentes páginas web sobre patrimonio forestal, las dedicadas a árboles monumentales (<http://old-trees.tripod.com>) y las numerosas publicaciones de catálogos nacionales como el de Francia (Bourdu, 1988), de áreas de Estados Unidos ( Van Pelt, 2001) o de Cataluña (Vinyeta, 1995), como ya recogían Donaire y Gordi (2003). ...
Este trabajo muestra las principales caracteristicas del sector turistico en Galicia en la actualidad, para a continuacion analizar las peculiaridades de un tipo concreto: el turismo forestal. El objetivo es destacar que el turismo forestal es una actividad con muchas posibilidades de desarrollarse en Galicia y que puede ejercer tanto como elemento dinamizador de ciertas comarcas rurales, como complemento a otras actividades turisticas que ya se desarrollan en el territorio gallego. Para alcanzar este objetivo, se analizan la distribucion y las caracteristicas de los montes y su relacion con la distribucion territorial de otros tipos de turismo como el turismo rural o el ecoturismo.
... In many cases, the diameter range of trees used to develop an equation did not extend throughout the diameter range of trees in our dataset. YOSE and SEKI contain some of the largest known individuals of ponderosa pine, sugar pine, white fir, red fir, and giant sequoia (Van Pelt 2001). Because destructive sampling is generally enjoined in the parks, allometric equations using large diameter trees do not exist. ...
Forest biomass on Sierra Nevada landscapes constitutes one of the largest carbon stocks in California, and its stability is tightly linked to the factors driving fire regimes. Research suggests that fire suppression, logging, climate change, and present management practices in Sierra Nevada forests have altered historic patterns of landscape carbon storage, and over a century of fire suppression and the resulting accumulation in surface fuels have been implicated in contributing to recent increases in high severity, stand-replacing fires. For over 30 years, fire management at Yosemite (YOSE) and Sequoia & Kings Canyon (SEKI) national parks has led the nation in restoring fire to park landscapes; however, the impacts on the stability and magnitude of carbon stocks have not been thoroughly examined.
The purpose of this study is to quantify relationships between recent fire patterns and aboveground tree carbon stocks in YOSE and SEKI. Our approach focuses on evaluating fire effects on 1) amounts of aboveground tree carbon on the landscape, and 2) rates of carbon accumulation by individual trees. In 2010, we compiled a database of existing plot data for our analyses. In 2011, our field crews acquired vegetation data and collected tree growth cores from 105 plots. In 2012, we completed an interpretive component and began data analyses. In 2013, processing of tree cores began. In 2014, final processing of tree cores, data analyses, and manuscript preparation was conducted. The work for this project was facilitated through an interagency agreement between the National Park Service and the U.S. Geological Survey, and through a Cooperative Ecosystems Studies Unit (CESU) agreement with the University of Washington.
In order to accurately quantify landscape-level carbon stocks, our analyses accounted for major sources of measurement errors, propagating those errors as we scaled plot-based carbon density estimates up to landscape-level totals. Using Monte Carlo simulation methods, we found that vegetation type mapping error was the largest source of uncertainty, while measurement uncertainties contributed by tree diameter measurements and tree diameter–biomass allometry equations were relatively minor.
For some forest types, we found differences in aboveground tree carbon densities between burned and unburned areas. For example, mean carbon density in burned red fir forests was estimated to be ~29% lower versus unburned areas. Alternative measures of fire history, such as time since fire and number of times burned, were poorly related to carbon densities.
Within YOSE, we evaluated the stability of landscape carbon pools by quantifying carbon stocks in areas of varying degrees of departure from historic fire return intervals. Of the ~25 Tg of total aboveground tree carbon in YOSE, ~10 Tg is contained within relatively stable areas (the next fire is unlikely to be high severity and stand-replacing), ~10 Tg occurs in areas deemed moderately stable, and the remaining ~5 Tg within relatively unstable areas.
We compared our landscape carbon estimates in YOSE to remotely-sensed carbon estimates from the NASA–CASA project and found that the two methods roughly agree. Our analysis and comparisons suggest, however, that fire severity should be integrated into future carbon mapping efforts. We illustrate this with an example using the 2013 Rim Fire, which we estimate burned an area containing over 5 Tg of aboveground tree carbon, but likely left a large fraction of that carbon on the landscape if one accounts for fire severity.
... This is the largest known WRC in the world, with a 19.5 ft (5.94 m) diameter at breast height and an estimated wood volume of 17650 ft 3 (500 m 3 ). 9 It is located »50 mi (80 km) from Tree Fever. Photo by Wsiegmund, Wikimedia Commons, reproduced under a CC-BY 2.5 license. ...
This editorial is about tree farming. It proposes to test in an experiment whether co-planting (in the same hole) western redcedar (WRC, Thuja plicata) with Sitka spruce (Picea sitchensis) protects WRC seedlings from wildlife browsing. This sustainable protection method is an alternative to the traditional use of mechanical devices and big-game repellents. Many repellents contain transient receptor potential (TRP) agonists, such as capsaicin, a TRP vanilloid-1 agonist. This editorial also delivers a puzzle: while herbivores avoid capsaicin, why do people living in hot climates consume large quantities of it (in chili peppers)?
... Coast redwood (Sequoia sempervirens, SESE) and giant sequoia (Sequoiadendron giganteum, SEGI) drew interest from early dendrochronologists because their decay-resistant heartwood, fire-resistant bark, and consequently great longevity provided access to intact millennium-scale tree-ring records. These are Earth's tallest, heaviest, and among the oldest trees [1,2] . Accurately dated treering series of these species (Figure 1A and 1B) can thus provide a reliable basis for numerous scientific applications, including climate reconstructions and physiological analyses. ...
Extremely decay-resistant wood and fire-resistant bark allow California's redwoods to accumulate millennia of annual growth rings that can be useful in biological research. Whereas tree rings of Sequoiadendron giganteum (SEGI) helped formalize the study of dendrochronology and the principle of crossdating, those of Sequoia sempervirens (SESE) have proven much more difficult to decipher, greatly limiting dendroclimatic and other investigations of this species. We overcame these problems by climbing standing trees and coring trunks at multiple heights in 14 old-growth forest locations across California. Overall, we sampled 1,466 series with 483,712 annual rings from 120 trees and were able to crossdate 83% of SESE compared to 99% of SEGI rings. Standard and residual tree-ring chronologies spanning up to 1,685 years for SESE and 1,538 years for SEGI were created for each location to evaluate crossdating and to examine correlations between annual growth and climate. We used monthly values of temperature, precipitation, and drought severity as well as summer cloudiness to quantify potential drivers of inter-annual growth variation over century-long time series at each location. SESE chronologies exhibited a latitudinal gradient of climate sensitivities, contrasting cooler northern rainforests and warmer, drier southern forests. Radial growth increased with decreasing summer cloudiness in northern rainforests and a central SESE location. The strongest dendroclimatic relationship occurred in our southernmost SESE location, where radial growth correlated negatively with dry summer conditions and exhibited responses to historic fires. SEGI chronologies showed negative correlations with June temperature and positive correlations with previous October precipitation. More work is needed to understand quantitative relationships between SEGI radial growth and moisture availability, particularly snowmelt. Tree-ring chronologies developed here for both redwood species have numerous scientific applications, including determination of tree ages, accurate dating of fire-return intervals, archaeology, analyses of stable isotopes, long-term climate reconstructions, and quantifying rates of carbon sequestration.
... The General Sherman tree, a giant sequoia (Sequoiadendron giganteum) of California, is the largest living thing on earth (274 feet tall, 27.1 feet in diameter, and an estimated total volume of 55,040 square feet), and given its enormous volume and average annual increment of growth it may be the fastest growing organism on earth (National Park Service, 2004). Coast redwood (Sequoia sempervirens) is the tallest tree on earth, with the current world height leader at 368.6 feet tall (Van Pelt 2001). And Montezuma baldcypress (T. ...
... In other cases, multiple reiterated trunks arise and compete with each other. The crowns of tall, old conifers often contain dozens of reiterated trunks emerging from the main trunk, other trunks, and limbs , Van Pelt 2001R. Van Pelt and S. C. Sillett, unpublished manuscript). ...
Sequoia sempervirens (redwood) is a long-lived, shade-tolerant tree capable of regeneration without disturbances and thus often present in all sizes within a single forest. In order to evaluate functional linkages among structures, plant distribution, and biodiversity in the canopy, we quantified all vascular plants from ground level to the treetops in an old-growth redwood forest (Prairie Creek Redwoods State Park, California, USA). This involved mapping terrestrial and epiphytic trees, shrubs, and ferns as well as climbing 27 trees up to 101 m tall within a 1-ha plot. We monitored canopy microclimates using sensor arrays that collected hourly data for up to 30 months. The plot held 4283 Mg/ha of aboveground dry mass in living plants, 95.4% of which was contributed by redwood. A high degree of structural complexity and individuality was evident in the crowns of the 14 largest trees in the form of reiterated trunks arising from main trunks, other trunks, and limbs. Thirteen species of vascular plants occurred as epiphytes in the plot, and all but one of these were restricted to the 14 largest trees. The evergreen shrub Vaccinium ovatum had the highest biomass of any epiphyte (212 kg/ha) followed by the evergreen fern Polypodium scouleri (196 kg/ha). The spatial aggregation of reiterated trunks was highly coincident with epiphyte masses, explaining 92% of the variation in fern and 75% of the variation in woody plant distribution along the vertical gradient. In addition to epiphyte biomass, there were 2366 kg/ha of soil in the canopy. Soils in crotches held 2-4 times as much water as soils on branches or limbs, and deeper layers held more water than shallower layers. During two years of monitoring, the volume of water stored in dead wood and soils in the canopy fluctuated between 24.7 m3 and 53.4 m3/ha. The vast majority of the plot's structure and arboreal habitats was held in the crowns of the 14 largest trees. Reiterated trunks and limbs on a small number of trees have important ecological functions in old-growth redwood forests, and it may be feasible to accelerate the development of structural complexity and biodiversity in maturing redwood stands.
... For example, Sequoia sempervirens [(D. Don) Endl.] reaches up to more than 115 m into the sky (Van Pelt, 2002). Trees are also one of the most long-lived life forms on earth and Bristlecone pines (Pinus longaeva [D.K. Bailey]) are the oldest living trees. ...
Trees are exceptional organisms that have evolved over some 385 million years and have overtaken other plants in order to harvest light first. However, this advantage comes with a cost: trees must transport water all the way up to their crowns and inherent physical limitations make them vulnerable to water deficits. Because climate change scenarios predict more frequent extreme drought events, trees will increasingly need to cope with water stress. Recent occurrences of climate change-type droughts have had severe impacts on several forest ecosystems. Initial experimental studies have been undertaken and show that stomatal control of water loss hinders carbon assimilation and could lead to starvation during droughts. Other mechanisms of drought-induced mortality are catastrophic xylem dysfunction, impeded long-distance transport of carbohydrates (translocation) and also symplastic failure (cellular breakdown). However, direct empirical support is absent for either hypothesis. More experimental studies are necessary to increase our understanding of these processes and to resolve the mystery of drought-related tree mortality. Instead of testing the validity of particular hypothesis as mechanisms of drought-induced tree mortality, future research should aim at revealing the temporal dynamics of these mechanisms in different species and over a gradient of environmental conditions. Only such studies will reveal whether the struggle for light will become a struggle for water and/or for carbon in drought-affected areas.
... The census protocol of measuring trees above any buttresses or obvious basal swelling or at 1·3 m, whichever point was lower, resulted in diameter being measured at 1·3 m for nearly all trees < 30 cm in diameter and > 2 m for most trees > 60 cm in diameter. This avoidance of buttresses and butt swell minimizes the inflation of diameter that occurs when large trees are measured at the traditional breast height Van Pelt (2001). ...
Summary • In the absence of wind, tree height is limited by elastic instability, which occurs when a tree becomes too spindly to erect itself when bent from the vertical. To assess the extent to which trees approach this limit and characterize species stature in diverse tropical forests, we measured tree dimensions in tall, dense forests at Lambir Hills, National Park, Sarawak, Malaysia and Pasoh Forest Reserve, Peninsular Malaysia. From these measurements we determined characteristic adult heights and trunk diameters for 91 species. • Across all species, adult height scaled with adult diameter to the 2/3 power, as predicted for a column at its buckling limit. These heights were, on average, 65% of the buckling limit calculated for a cylindrical column with typical wood properties. • At a given diameter, the species of Lambir were 9% taller than those of Pasoh, a pattern related to the greater rainfall and density of trees at Lambir. • On the topographically rugged Lambir plot, large emergent trees were shorter on ridges than in hollows, whereas small, sheltered trees showed no relation between allometry and elevation. • Thus, trees may approach gravitational limits to height in favourable environments for growth where there are large advantages of height for light interception and trees are sheltered from wind.
... Between approximately ad 1650 and 1850, the Sierra Nevada experienced a period of cool and dry temperatures – the local manifestation of the Little Ice Age northern hemispheric cooling (Stine, 1996). This period, from 360 to 160 years ago, corresponds to the inferred establishment dates of many dominant trees in Yosemite, although older trees would have established in the warmer and wetter period before 1650 (Stine, 1996;Van Pelt, 2001). The trees that now represent the forest canopy would therefore have experienced their period of rapid growth during the different climatic conditions of the Little Ice Age. ...
Aim (1) To calculate annual potential evapotranspiration (PET), actual evapotranspiration (AET) and climatic water deficit (Deficit) with high spatial resolution; (2) to describe distributions for 17 tree species over a 2300-m elevation gradient in a 3000-km² landscape relative to AET and Deficit; (3) to examine changes in AET and Deficit between past (c. 1700), present (1971–2000) and future (2020–49) climatological means derived from proxies, observations and projections; and (4) to infer how the magnitude of changing Deficit may contribute to changes in forest structure and composition.
... Tree ring chronologies from large trees provide long records of past forest development and disturbance [16], as well as proxy records of annual climatic variation [17]: they are an important source of the data required to test and refine ecological theories and models. Large trees are culturally [18] and spiritually important [19] in many societies; individuals and organizations maintain large tree registries (e.g., [20]), and government agencies manage parks and preserves dedicated to the conservation of exceptionally large trees, such as Redwood and Sequoia & Kings Canyon National Parks in California, USA. Populations of large-diameter trees can be intractable study subjects. ...
Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m(2). We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances
... Giant sequoias have attained a special fame because of their huge size and longevity. They are the largest trees in existence, with bole volumes of nearly 1,500 m 3 and heights measured up to 307 feet (Van Pelt 2001). Precise tree dates as old as 3,266 years have been measured in giant sequoia Pinus jeffreyi 2 ...
Olympic National Park exists as an island of protected land on the Olympic Peninsula, surrounded by multiple jurisdictions of managed lands and ultimately by the Pacific Ocean, Strait of Juan de Fuca, and Puget Sound. Within this geographical context, OLYM is tasked with conserving and managing aquatic resources that are harvested both inside and outside of the park’s boundaries, and that spend much of their life cycle in the ocean, where they are subject to a host of other natural and anthropogenic pressures. In this section, we address two harvested resources of concern to the park. First, we consider the condition of Pacific salmonids in the park (Chapter 4.2.1). The park contains key freshwater habitat for Pacific salmonids where they are protected from harvest, have productive conditions for spawning and rearing, and provide critical ecological functions. These salmonids are also part of sport, commercial, ceremonial and subsistence fisheries outside the park. Here, we carefully examine 17 salmonid stocks on five park rivers to address the influence of a century of harvest and hatchery practices. Second, we assess the condition of a population of razor clams found on OLYM’s Kalaloch Beach (Chapter 4.2.2). Razor clams are harvested within the park’s boundaries, leading to unique challenges balancing tribal and public harvest opportunities with a sensitive and declining population whose dynamics are not well understood.
Duda, J.J., S.J. Brenkman, and P. Crain. 2018. Ch. 4: Pacific Salmonids. Pages 123-167 in R. McCaffery and K. Jenkins, editors. Natural resource condition assessment: Olympic National Park. Natural Resource Report NPS/OLYM/NRR—2018/1826. National Park Service, Fort Collins, Colorado.
Main target of this thesis was the research of the present status as well as the evaluation of growth chances of western redcedar in eastern Germany. Furthermore, the work describes the biological diversity of redcedar stands and their expansion ability in order to estimate the ecological consequences of the naturalization of this species for our forests. Research was conducted on 22 experimental plots established by Professor Schwappach at the end of the nineteenth century and 18 longterm Thuja plicata research plots installed in Eberswalde after World War II. Those plots were established on sites of different fertility: fresh mixed coniferous forest, fresh mixed broadleaved forest and fresh broadleaved forest. The thesis considers all collected up to now archived data as well as the results of the measurement taken by the author during the last inventory of the research plots.
The analysis of productivity showed that the average height (HG) and the QMD (DG) of the oldest Thuja plicata stands {123–130 years} reached 25-39 m and 54-63 cm respectively. The tallest tree was 43.6 m high and 97.3 cm thick. The annual and average development of height and breast height diameter in the analysed redcedar stands came to their culmination at the age of 20 and 30 or 10 and 20 respectively. The timber volume in these stands {number of trees 170-547 per 1 ha; stand basal area 39.1–81.5 m²/ha} oscillated between 397.5 and 975.1 m³/ha. So at the age of 120, it was 192 m³ (24.5 %) higher than that of the Scots pine stands of the best yield class in the State of Brandenburg. The total timber yield of the youngest investigated stands {50–54 years} achieved maximum 1,000 m³/ha, that is equivalent to the observed achievement of aged 110 pine stands of the 1st yield class.
The trunks of most of the individuals are relatively straight but, caused by their negligible ability of natural pruning, branchy. Therefore, in order to obtain high quality timber, pruning is absolutely essencial. A little more than 10 % of the trees in the oldest redcedar stands were characterized by bottle shaped bulges at the butt and sabre-like form of the trunk. The most important health issue of western redcedar in the investigated stands is the incidence of annosum root rot (Heterobasidion annosum (Fr.) Bref.). Whereas at the age of 50 only 8 % of the trees were infected by this fungus, in the oldest stands the root rot was detected at 38 % of the individuals. Observation in the research area confirmed the statements of other authors regarding the proportionally high suspectibility to strong wind action.
Most of the natural rejuvenation of western redcedar was observed in the immediate vicinity of the investigated stands, at a maximum distance of 100 m.
The major limiting natural rejuvenation factor for western redcedar is damage caused by game animals, mostly browsing and cleaning antlers. At the same time, intensive infiltration of Thuja plicata stands by natural rejuvenation of other tree species (mostly beech and hornbeam) from the surrounding stands was detected.
Both, the short maximum distance from the centre of the analysed areas and the sporadical appearance of natural rejuvenation of redcedar are evidence to the lack of endangerment of the native flora by Thuja plicata.
The inventory of dead wood in Schwappach’s stands displayed their relatively large volume (66.9 m³/ha) that exceeded three times the average dead wood volume ascertained during the last large-area inventory in the German forests (BWI3). Floristic research in those redcedar stands showed a bit larger abundance in comparison to its neighbourhood (redcedar: 23 species on average {8 .. 42}; neighbourhood (characteristic of the surroundings in chapter 11, tab. 59): 21 species on average {8 .. 38}).
The results of the analysis of redcedar plots growing under pine canopy of different stand density verify the well-known in literature high shade tolerance of this species. However, comparison of the productivity of redcedar coming from open areas illustrates high deficites for those grown under canopy. Depending on the density of the pine canopy, the deficites measured on the total timber yield in 50 years old stands ranged between 647 and 770 m³/ha. Total timber yield of a pine-redcedar stand aged 93, was 201.1 m³/ha higher than that of the comparative 91 years old pure pine plantation.
On the one hand, tending strategies as medium (on sites of average fertility) or strong (on sites of higher fertility) high-tinning result in higher total timber yield, on the other hand, they allow for preservation of the multilevel ecology of western redcedar and ensure high technical wood quality of the stems.
ContextWestern Olympic valley bottoms, disturbed by alluvial processes, are dominated by Picea sitchensis and isolated cohorts of Pseudotsuga menziesii, while upland contexts, disturbed by wind and fire, are dominated by P. menziesii. These forests have distinct structure and produce large trees with habitat for endangered birds.Objectives
Describe how disturbance and forest development create landscape forest patterns and distribution of large trees in valley bottom and upland forests.Methods
LiDAR data of ~ 9700 ha within Olympic National Park, USA was classified based on vegetation height and percent cover to contrast valley bottom and upland forests. Within-crown structure from 36 P. sitchensis and 12 P. menziesii was then used to predict locations of the largest and most complex trees.ResultsValley bottoms comprise small patches of dense tall (11%), medium-height trees (19%), and gaps (7%) embedded in open-canopy forest with scattered tall trees (63%). Upland forests comprise larger patches of tall (16%), medium (58%), and open-canopy forest (25%) with few gaps (1%). The largest trees are more abundant in valley bottoms (0.05 tree ha−1) than upland (0.02 tree ha−1) due to small patches of tall trees within open-canopy forest.Conclusions
Alluvial disturbance, fungi-wind interaction, and dominance of late-successional fast-growing P. sitchensis create open-canopy forest with more large trees, while severe fire and wind interacting with P. menziesii create patchy closed-canopy forest with fewer large trees. Management for large habitat trees should use aggregated retention with P. menziesii, multi-aged selection techniques with P. sitchensis, and indefinitely retain a low density of large trees.
Subalpine forests of California comprise the highest elevation ecosystems that are dominated by upright trees. They are defined as a zone influenced primarily by abiotic controls, including persistent snowpack, desiccating winds, acute and chronic extreme temperatures, soil moisture and evapotranspirative stresses, and short growing seasons. Bounded at the upper elevation by the forest-alpine treeline ecotone, the forests persist under conditions of deep snows and exposure to severe winds and high solar radiation. Most subalpine forests in California are sparse woodlands, with short statured individuals, and wide spacing of young as well as old trees, commonly interrupted by areas of exposed rock, dry upland slopes, meadows, and lakes. Subalpine forests in California have an uncertain future under changing climates, with some projections showing very high losses if species move upslope and off mountain summits with warming while others suggesting that environmental heterogeneity could afford adequate refugia for long term species persistence.
A review of the biology and taxonomy of Pseudotsuga menziesii, with emphasis on forestry.
This work, which i did as a master student in 2004, is a littereature review on the processes of lignin decomposition and its implication in soil humus formation
Research highlights
► Studies the Tualatin River in the Pacific Northwest, US to predict the impact of climate change on ecohydrologic parameters. ► Results show increased future storm flows based on current emissions trends. ► Significant impacts to hydrologic ecotones and LiDAR-derived vegetative features is anticipated.
A vegetation chronosequence spanning over 300 years was established in unconstrained reaches of the lower Queets River in Olympic National Park, Washington, USA, for an examination of riparian successional patterns. The Queets is an unconstrained, dynamic, mountain river located within a temperate rain forest environment. Ongoing chan- nel movements create intricate patterns in the physical structure of the valley. Twenty-one plots containing a total of 4359 trees were mapped and measured for structural and crown characteristics. Snags, logs, and understory vegetation were also quantified. Recent alluvial deposits are colonized primarily by early-successional trees Salix sitchensisand Alnus rubra. Conifer seedlings, primarily Picea sitchensis, generally invade after the initial cohort of hardwood trees begins senescence: 20-30 years for Salix and 40-60 years for Alnus. Through accumulation of sediments from floods and channel downcutting, surfaces become perched above the reach of annual floods after 40-80 years and are then slowly colonized by late successional tree species Acer circinatum, Acer macrophyllum, and Tsuga hetero- phylla. Diverse, old-growth forests ultimately develop after 200-250 years, containing some of the largest known trees in the Pacific Northwest. However, canopy and stem densities remain lower than comparative Pseudotsuga menziesii forests from the nearby Cascade Mountains. Vast individual crowns can develop, with occasional Picea up to 25 m wide and 70 m deep. Individual stands may accumulate .200 000 m3/ha of canopy volume— among the highest recorded on earth. Mixed among the generalized successional sequence are variations created by uncommon channel movements. Avulsions followed by channel incision form cobblefields in abandoned channels or other surfaces which are isolated from subsequent inundation and sediment deposition. These cobblefields embark on a different successional trajectory, which often includes conifer seedlings present in the initial cohort. Ultimately, whatever the initial trajectory, soils become productive due to soil conditioning by Alnus and the decomposition of other plant material. These biophysical complexities, interconnected patterns, and system-scale resilience are summarized in a multiple-pathway successional model that may be applicable to floodplain riparian forests throughout much of the Pacific coastal ecoregion.
Stem diameter at breast height (DBH) and tree height (H) are commonly used measures of tree growth. We examined patterns of height growth and diameter growth along a stem using
a 20-year record of an even-aged hinoki cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl.) stand. In the region of the stem below the crown (except for the butt swell), diameter growth rates
(ΔD) at different heights tended to increase slightly from breast height upwards. This increasing trend was pronounced in suppressed
trees, but not as much as the variation in ΔD among individual trees. Hence, ΔD below the crown can be regarded as generally being represented by the DBH growth rate (ΔDBH) of a tree. Accordingly, the
growth rate of the stem cross-sectional area increased along the stem upwards in suppressed trees, but decreased in dominant
trees. The stem diameter just below the crown base (DCB), the square of which is an index of the amount of leaves on a tree, was an important factor affecting ΔDBH. DCB also had a strong positive relationship with crown length. Hence, long-term changes in the DCB of a tree were associated with long-term changes in crown length, determined by the balance between the height growth rate
(ΔH) and the rising rate of the crown base (ΔHCB). Within the crown, ΔD's were generally greater than the rates below the crown. Even dying trees (ΔD ≈ 0 below the crown) maintained ΔD > 0 within the crown and ΔH > 0 until about 5 years before death. This growth within the crown may be related to the need to produce new leaves to compensate
for leaves lost owing to the longevity of the lower crown. These results explain the different time trajectories in DBH–H relationships among individual trees, and also the long-term changes in the DBH–H relationships. The view that a rise in the crown base is strongly related to leaf turnover helps to interpret DBH–H relationships.
CONTENTS: Summary 1 I. Introduction 1 II. Giant eucalypts in a global context 2 III. Giant eucalypts - taxonomy and distribution 4 IV. Growth of giant eucalypts 6 V. Fire and regeneration of giant eucalypts 8 VI. Are giant eucalypts different from other rain-forest trees? 9 VII. Conclusions 10 Acknowledgements 11 References 11 SUMMARY: Tree species exceeding 70 m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fire-intolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for 'hyper-emergence'. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr.
Using rope techniques for access, we surveyed epiphytes on five Sitka spruce trees up to 92 m tall in an old-growth redwood forest. We quantified epiphyte diversity by sampling 5% of each tree's surface area of axes (branches >5 cm diameter) and branchlets (branches <5 cm diameter, including foliage). Epiphyte communities included 57 macrolichen, 15 crustose lichen, 17 bryophyte, and two fern species. The five most abundant species—Isothecium myosuroides, Polypodium scouleri, Polypodium glycyrrhiza, Lobaria pulmonaria, and Frullania nisquallensis—contributed 42.1, 13.3, 8.4, 6.7, and 4.7% of the total epiphyte biomass, respectively. There was an average of 36.2 kg of bryophytes, 9.9 kg of lichens, 12.7 kg of ferns, and 131 kg of associated dead organic matter per tree. Axes supported 83% of the biomass and 98% of the dead organic matter. At the whole-tree level, bryophyte biomass was 11.3 times higher and lichen biomass was 2.5 times lower on axes than branchlets. Ferns were restricted to axes. Ordination analysis revealed one dominant gradient in epiphyte composition that was positively correlated with height and lichen diversity, and negatively correlated with bryophyte diversity. Chlorolichens dominated the exposed portion of the gradient with equivalent amounts of cyanolichens and bryophytes. Mosses dominated the intermediate portion of the gradient with equivalent amounts of liverworts, cyanolichens, and chlorolichens. There was very little lichen cover in the sheltered portion of the gradient, which was dominated by bryophytes. Extensive bryophyte mats with large quantities of dead organic matter promote biological diversity on Sitka spruce in redwood forest canopies by storing water and serving as habitats for desiccation-sensitive organisms.
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