Constance Harrington

US Forest Service | FS · Pacific Northwest Research Station

Phenology of diameter growth in trees has been studied for many years but generally using a limited number of sites and genotypes. In this project provenances of Douglas-fir ( Pseudotsuga menziesii var. menziesii ) planted across a wide range of environments were used to evaluate diameter growth and phenology to an extreme heat event and to seasona...

Height growth in trees is expensive in terms of the amount of stem tissue required to maintain productive tissue in sunlight. However, shifting allocation from stem support to leader growth and foliage production may allow trees to minimize shading effects on photosynthesis, especially for shorter trees within the population. This hypothesis was ev...

Height growth in trees is expensive in terms of the amount of stem tissue required to maintain productive tissue in sunlight. However, shifting allocation from stem support to leader growth and foliage production may allow trees to minimize shading effects on photosynthesis, especially for shorter trees within the population. This hypothesis was ev...

Key message Planting sites that are cooler, with more precipitation, early springs, high TD and hot dry summers reduce bole taper in young Douglas-fir trees. Seed-source climates that are drier, with high TD and low snowfall produce seed-sources with lower taper. Abstract Analysis of a 10 year reciprocal transplant study was performed to determine...

Do trees adjust support costs to the stem in order to maintain or boost allocation to foliage to compete for light? This question was addressed with data collected from three, long-term studies investigating the growth effects of controlled levels of competition for Alnus rubra , Pseudotsuga menziesii , and Pinus resinosa . Costs and benefits of ma...

Old-growth forests serve as critical habitat for many sensitive species, but management practices have diminished their prevalence, and former regions of old-growth are now dominated by second-growth stands lacking the structural heterogeneity, diversity, and species richness that these older forests possess. In western Washington state in the Paci...

To better understand hydraulic adaptations of coastal Douglas-fir (P. menziesii var. menziesii (Mirb.) Franco) to local climate, we examined genetic (G) and environmental (E) responses of branch hydraulic architecture of 7-year-old saplings from dry and wet climates of origin grown at a relatively dry and a relatively wet common garden site in west...

Promoting patchy recruitment of shade tolerant tree species into the midstory is an important step in developing structural diversity in second-growth stands. Variable-density thinning (VDT) has been proposed as a strategy for accelerating structural diversity, as its combination of within-stand treatments (harvest gaps, thinning, and non-harvested...

Standardizing gross volume increment on periodic height increment of the dominant trees minimizes the effects of site quality and age in growth-growing stock relations; however, volume increment per height increment contains more information than just a normalization method for fitting growth models. This study builds upon previous work suggesting...

In recent years, many forest managers have become interested in managing forests for a wider range of objectives than previously. As an initial or intermediate treatment, variable-density thinning (VDT) can help meet objectives such as improving wildlife and plant habitats, increasing structural and compositional diversity, and enhancing aesthetic...

Shrubs are an important component of terrestrial plant communities in both forested and nonforested ecosystems, but relatively little information is available on their distributions. This project provides mapped occurrences for 78 native shrub species found in the Pacific Northwest (Oregon, Washington, Idaho, and western Montana) as derived from tw...

Climate change is shifting both the habitat suitability and the timing of critical biological events, such as flowering and fruiting, for plant species across the globe. Here, we ask how both the distribution and phenology of three food-producing shrubs native to northwestern North America might shift as the climate changes. To address this questio...

Climate change is altering the suitable habitat and phenology of plant species around the world, with cascading effects on people and animals reliant upon those plant species as food sources. Huckleberry (Vaccinium membranaceum) is one of these important food-producing plant species that grows in the Pacific Northwest of North America. Here, we mod...

Wound closure is an important component of tree recovery from bole damage. Damage to young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands in the precommercial and commercial stages is common, yet few studies have looked at how trees at these stages of stand development respond to common forms of damage. Using data from a 10-year study of...

Background Experiencing an adequate amount of cold temperatures over winter is necessary for many temperate tree species to break dormancy and flower in spring. Thus, changes in winter and spring temperatures associated with climate change may influence when trees break dormancy and flower in the future. There have been several experimental studies...

Raw data: temperature data for all treatments from 1/2/2016 through 4/6/2017

Raw data: dates of reproductive budburst of red alder cuttings in all treatments

Supplemental Information and code S1. Chilling and forcing functions used to estimate the ”possibility-line” for reproductive budburst of red alder. S2. Code for all analyses in manuscript. Code was run in the statistical program R (R Core Team, 2017).

We applied a range of bole and root damage treatments to young Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees. Significant natural damage occurred to tree crowns over the course of the 10-year study allowing for an analysis of how damage severity to tree boles, tree roots, and tree tops impacts growth and cumulative survival of trees. Tre...

Background . Experiencing an adequate amount of cold temperatures over winter is necessary for many temperate tree species to break dormancy and flower in spring. Thus, changes in winter and spring temperatures associated with climate change may influence when trees break dormancy and flower in the future. There have been several experimental studi...

Background . Experiencing an adequate amount of cold temperatures over winter is necessary for many temperate tree species to break dormancy and flower in spring. Thus, changes in winter and spring temperatures associated with climate change may influence when trees break dormancy and flower in the future. There have been several experimental studi...

Trees have evolved to time flowering to maximize outcrossing, minimize exposure to damaging frosts, and synchronize development with soil moisture and nutrient availability. Understanding the environmental cues that influence the timing of reproductive budburst will be important for predicting how flowering phenology of trees will change with a cha...

Young stands are commonly assumed to require centuries to develop into late-successional forest habitat. This viewpoint reflects the fact that young stands often lack many of the structural features that define late-succes-sional habitat, and that these features derive from complex stand dynamics that are difficult to mimic with forest management....

Seed-source movement trials using common garden experiments are needed to understand climate, tree (host), and pathogen interactions. Douglas-fir (Pseudotsuga menziesii var menziesii) is an important tree species native to western North America influenced by the foliar fungi Phaeocryptopus gaeumannii, a biotroph and causal agent of Swiss needle cas...

This report gives early results, 18 years after treatment and 30 years after planting, from a trial of early thinning and gap creation intended to increase biodiversity in a very uniform extensive Douglas-fir plantation. Gap creation has introduced canopy irregularity and a substantial hemlock component into what was originally a very uniform pure...

This study evaluated relationships between site or tree characteristics and below-ground materials in Douglas-fir forests of the Pacific Northwest. We core-sampled living roots, dead organic matter, and mineral fragments at three soil depths on a 300-sample grid at nine forested sites in western Washington and Oregon resulting in approximately 7200...

This report gives early results, 18 years after treatment and 30 years after planting, from a trial of early thinning and gap creation intended to increase biodiversity in a very uniform extensive Douglas-fir plantation. Gap creation has introduced canopy irregularity and a substantial hemlock component into what was originally a very uniform pure...

The phenology of diameter-growth cessation in trees will likely play a key role in mediating species and ecosystem responses to climate change. A common expectation is that warming will delay cessation, but the environmental and genetic influences on this process are poorly understood. We modeled the effects of temperature, photoperiod and seed-sou...

Climate change is causing rapid changes to forest disturbance regimes worldwide. While the consequences of climate change for existing disturbance processes, like fires, are well studied, emerging drivers of disturbance such as snow loss and subsequent mortality are much less documented. As the climate warms, a transition from winter snow to rain i...

Under climate change, the reduction of frost risk, onset of warm temperatures and depletion of soil moisture are all likely to occur earlier in the year in many temperate regions. The resilience of tree species will depend on their ability to track these changes in climate with shifts in phenology that lead to earlier growth initiation in the sprin...

Methods S1. Combinations of Minimum Cold Month Temperature and Mean Summer Precipitation of the location where seeds for each population were collected. Methods S2. Experimental design.

Drought and freeze events are two of the most common forms of climate extremes which result in tree damage or death, and the frequency and intensity of both stressors may increase with climate change. Few studies have examined natural covariation in stress tolerance traits to cope with multiple stressors among wild plant populations. We assessed th...

Past studies have documented differences in epicuticular wax among several tree species but little attention has been paid to changes in accumulation of foliar wax that can occur during the year. We sampled current-year needles from the terminal shoots of Douglas-fir (Pseudotsuga menziesii var. menziesii) in late June/early July, late August and ea...

The success of conifers over much of the world's terrestrial surface is largely attributable to their tolerance to cold stress (i.e.,cold hardiness). Due to an increase in climate variability, climate change may reduce conifer cold hardiness, which in turn could impact ecosystem functioning and productivity in conifer-dominated forests. The express...

Many temperate and boreal tree species have a chilling requirement, that is, they need to experience cold temperatures during fall and winter to burst bud normally in the spring. Results from trials with 11 Pacific Northwest tree species are consistent with the concept that plants can accumulate both chilling and forcing units simultaneously during...

There is a general assumption that intraspecific populations originating from relatively arid climates will be better adapted to cope with the expected increase in drought from climate change. For ecologically and economically important species, more comprehensive, genecological studies that utilize large distributions of populations and direct mea...

We developed a new climate-sensitive vegetation state-and-transition simulation model (CV-STSM) to simulate future vegetation at a fine spatial grain commensurate with the scales of human land use decisions, and under the joint influences of changing climate, site productivity, and disturbance. CV-STSM integrates outputs from four different modelin...

Pecan (Carya illinoiensis) and white oak (Quercus alba) produce multiple products and wildlife values, but their phenological responses to N fertilization have not been well characterized. We compared tree growth at planting and for six consecutive growing seasons during establishment (2003–2008, Test 1), and determined if phenology of budburst, le...

Forest residual biomass harvesting is a potential concern in regions where this primarily branch and needle material is removed to provide a source of renewable energy or where total-tree yarding takes place. Concern arises from the removal of nutrients present in residual biomass, as well as from heavy equipment trafficking used to collect the mat...

In the Willamette Valley–Puget Trough–Georgia Basin ecoregion of the North American Pacific Northwest, there has been widespread encroachment of Douglas-fir (Pseudotsuga menziesii) upon Oregon white oak (Quercus garryana) savanna and woodland stands that were historically maintained by frequent anthropogenic fire. Restoration of these stands requir...

We sampled trees grown with and without competing vegetation control in an 11-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) plantation on a highly productive site in southwestern Washington to create diameter- based allometric equations for estimating individual-tree bole, branch, foliar, and total aboveground biomass....

Forest growth models are useful for asking "What if?" questions when evaluating silvicultural treatments intended to increase the complexity of future stands. What if we thinned to level A or B? How would it af ect the growth rates of understory trees? How many trees would survive? To answer these types of questions, a growth model needs to accurat...

The timing of periodic life cycle events in plants (phenology) is an important factor determining how species and populations will react to climate change. We evaluated annual patterns of basal-area and height growth of coast Douglas-fir (Pseudotusga menziesii var. menziesii (Mirb.) Franco) seedlings from four seed sources that were planted in four...

Background/Question/Methods Climate adaptation planning faces three central types of uncertainties: How much climate change will occur? How will ecosystems respond to a given level of climate change? How will people respond to resultant changes in ecosystems? We address these issues by using an agent-based modeling system that simulates the inter...

Background/Question/Methods The processes that change climate, succession and land-use occur at different time scales and therefore contribute to complex feedbacks between human activities and ecosystems. Understanding the interactions among these processes is essential to evidence-based land-use decision making. We developed a new vegetation mode...

Background/Question/Methods Models to predict the timing of budburst are needed to help predict some of the effects of climate change on ecosystems. Many studies have demonstrated that overwintering buds sense cold temperatures (chilling) and warm temperatures (forcing), but the way different temperatures contribute towards chilling and forcing s...

Port-Orford-cedar is of interest to ecologists and foresters, but little information is available on its growth, its genetic variation, or the field performance of families selected for resistance to root disease. Survival, damaging agents, and growth were evaluated for nine families at three outplanting sites in south coastal Oregon. Survival was...

In young plants of many woody species, the first flush of growth in the spring may be followed by one or more flushes of the terminal shoot if growing conditions are favorable. The occurrence of these additional flushes may significantly affect crown form and structure. Apical dominance (AD) and apical control (AC) are thought to be important contr...

Despite widespread use of intensive vegetation control (VC) in forest management, the effects of VC on allocation of biomass and nutrients between young trees and competing vegetation are not well understood. On three Pacific Northwest sites differing in productivity, soil parent material, and understory vegetation community, we evaluated year-5 ef...

Many land managers are interested in maintaining or restoring plant communities that contain Oregon white oak (OWO, Quercus garryana), yet there is relatively little information available about the species' growth rates and survival to guide management decisions. We used two studies to characterize growth (over multi-year periods and within individ...

Forest Ecology and Management j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / f o r e c o a b s t r a c t Climate change resulting from increased concentrations of atmospheric carbon dioxide ([CO 2 ]) is expected to result in warmer temperatures and changed precipitation regimes during this century. In the northweste...

Diurnal fluctuation in a tree's stem diameter is a function of daily growth and of the tree's water balance, as water is temporarily stored in the relatively elastic outer cambial and phloem tissues. On a very productive site in southwestern Washington, U.S.A., we used recording dendrometers to monitor stem diameter fluctuations of Douglas-fir at p...

Height growth by year and by individual cycle on the terminal shoot was reconstructed from stem analysis for 45 loblolly pine (Pinustaeda L.) trees that were 35 years old. Sample trees represented three seed sources (Clark County, AR; Livingston Parish, LA; and Onslow County, NC), each of which had been planted at three installations (Arkadelphia,...

Specific gravity of breast-high wood did not vary significantly among ten 9-year-old sources used in an Alnusrubra (Bong.) provenance trial. Correlations between specific gravity and diameter were also nonsignificant. In a study of seven natural stands selected to cover a range of site conditions, specific gravity did not differ among stands and wa...

Juvenile height growth of Sitka alder (Alnussinuata (Regel) Rydb.), a nitrogen-fixing shrub, was examined on eight sites. The potential compatibility of mixed stands of Sitka alder and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was then assessed by comparing height-growth curves of the two species at early ages. Based on Sitka alder's low he...

Two studies were established to investigate factors influencing sprouting of red alder (Alnusrubra Bong.). In the first study, 4-year-old planted trees were cut at five stump heights (0, 10, 30, 50, and 70 cm) during 4 months of the year (January, May, July, and September). The percent of stumps surviving was greatest with cuts in January at 30 cm...

Growth and yield of black cottonwood (Populustrichocarpa Torr. and Gray) and red alder (Alnusrubra Bong.) were measured at four successive 2-year coppice harvests. Three levels of amended pulp mill sludge (450, 225, and 0 t•ha−1) were applied before planting, and one-half of the plots were irrigated during the 2-year establishment period prior to t...

Important site and tree characteristics of Thuja plicata were examined in 19 natural stands in the coastal and interior zones of W Washington, Oregon, and in W Vancouver Island, British Columbia. Foliar concentrations of red cedar were especially low in Mn and Al and high in Ca and Mo. Site index was correlated positively with N, the chlorophylls,...

The relationship between cross-sectional root area at groundline and composite root area (the sum of the areas of the first-order lateral roots plus the area of the taproot subtending the most distal lateral root) was examined in 3- to 9-year-old loblolly and shortleaf pine (Pinustaeda L. and P. echinata Mill.). For both species, root area at groun...

Six-year-old loblolly pine seedlings were subjected to root severing treatments varying from 0 to 100% of first-order lateral roots. Separate treatments severed surface-oriented or deep-oriented roots. Plant water status was monitored periodically for several months. After all measurements were taken, gross root system structure was determined by e...

Seven silvicultural treatments were applied to a 15-20-yr-old, naturally regenerated Thuja plicata stand growing on a poor-quality site in W Washington. Treatments were: unthinned, unfertilized (untreated); unthinned, fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate; thinned, unfertilized; thinned, fertilized with urea;...

Height growth of loblolly pine (Pinustaeda L.) was measured in trees subjected to one of five irrigation and fertilization regimes in a closely spaced genetic test for 3 years. Shoot components of 3rd-year annual height increment were measured over two contrasting treatments. Juvenile height and number of stem units in summer growth length in the f...

We examined the relationships between biomass or growth rates and leaf characteristics of 2-year-old trees of two clones of Populus. Leaf characteristics were total plant leaf area or leaf weight, mean size (or weight) of fully expanded terminal leaves, and foliar concentrations and contents of N, P, K, Ca, Mg, total chlorophyll, and total availabl...

Models to predict budburst and other phenological events in plants are needed to forecast how climate change may impact ecosystems and for the development of mitigation strategies. Differences among genotypes are important to predicting phenological events in species that show strong clinal variation in adaptive traits. We present a model that inco...

Western redcedar (Thuja plicata Donn ex D. Don.) is an important North American tree species, but little information is available on its long-term responses to silvicultural treatments. Stand responses (mortality, ingrowth, basal area and volume growth, and distributions of trees by diameter and height classes) were followed for 25 years after thin...

We assessed various combinations of storage factors: bag type, temperature, duration, and antifungal pre-storage treatments for white oak acorn storage, using Oregon white oak (Quercus garryana Douglas ex Hook. [Fagaceae]) acorns from 7 seed sources. Acorn viability remained high (84%), even after 2 y of refrigerated storage, but the majority of th...

Midcanopy layers are essential structures in “old-growth” forests on the Olympic Peninsula. Little is known about which stand and tree factors influence the ability of midcanopy trees in young-growth forests to respond to release; however, this information is important to managers interested in accelerating development of late-successional structur...

Most temperate woody plants have a winter chilling requirement to prevent budburst during mid-winter periods of warm weather. The date of spring budburst is dependent on both chilling and forcing; modeling this date is an important part of predicting potential effects of global warming on trees. There is no clear evidence from the literature that t...

We reconstructed the stand structure and composition for two western Washington old-growth forest stands harvested around 1930 (named Fresca and Rail) from field and historical data. Both old-growth stands had a codominant or dominant 250-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) overstory with a few scattered older Douglas-fir. W...

The extent of oak woodland and savanna habitat in the Pacific Northwest has been dramatically reduced since settlement in the mid-1800s. This report presents a practical guide for landowners and managers who are interested in reestablishing native oak by planting seedlings. Keys to successful establishment are (1) planting quality seedlings, (2) co...

Western redcedar (Thuja plicata Donn ex. D. Don) is of high commercial value, is considered highly shade tolerant and occurs more commonly in mixed-species, uneven-aged stands than in pure stands. Successful maintenance of redcedar as a component of mixed-species stands to enhance diversity or to overcome the difficulties of establishing redcedar r...

Western redcedar (Thuja plicata) and yellow-cedar (Callitropsis nootkatensis, syn Chamaecyparis nootkatensis) are important tree species in both ecological and economic terms but relatively little information has been available on their growth rates under different stand and site conditions. We took a "data-centric" approach to ask: (1) which envir...

Background/Question/Methods Projecting climate change effects on coupled natural/human systems at local landscape extents is crucial for land use planning and policy development. We describe an approach to modeling interactions and feedbacks between human and natural systems under the joint influences of climate change and human population growth....

We related intra-annual patterns in radial growth rate and xylem density to foliar phenology and second growth flushes in a young Douglas-fir plantation in western Washington. Three foliar maturity classes were defined: (1) shoots and needles elongating; (2) elongation complete, needles maturing; and (3) needles mature. Diameter growth rate had two...

Planting with mixtures of tree species rather than single species is often considered during reforestation because of the potential increased productivity and other benefits. We examined tree growth at the stand and individual tree scales in two experiments contrasting monocultures with a 1:1 mixture of tree species: (1) Douglas-fir (Pseudotsuga me...

Intra-annual growth rates were assessed during 3years for four Populus clones grown in pure and mixed clonal stands at square spacings of 0.5, 1.0 and 1.5m in western Washington, USA. Height growth rate peaked in August, except at the 0.5-m spacing where it peaked in July and June in years 2 and 3, respectively. Diameter growth rate generally peake...

Growth and mortality of coast Douglas-fir (Pseudotsuga menziesii var. menziesii) were studied for 25 years after planting seedlings at 1-6-m spacings on a site of moderate quality in the western Cascade Mountains of Washington. Responses were compared to those from two other studies representing high and low site qualities. Third-year height did no...

There is little information available on the long-term effects of managing western redcedar (Thuja plicata Donn ex D. Don). In a 15- to 20-year-old naturally regenerated second-growth redcedar stand on a poor site on the Olympic Peninsula of Washington, we tested crop tree (largest 250 trees·ha-1) response to precommercial thinning and fertilizatio...

What roles do ruderals and residuals play in early forest succession and how does repeated disturbance affect them? We examined this question by monitoring plant cover and composition on a productive site for 6 years after clear-cutting and planting Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). The replicated experiment included three treatme...