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Waterlogging Tolerance of Lowland Tree Species of the South
Abstract
Many tree species in the South are adapted to periodic and/or prolonged soil waterlogging. However, artificial disturbances of natural water regimes sometimes cause flooding to occur at abnormal times or the flood water to be deeper and waterlogging longer in duration than is normal. As a consequence, it is difficult for forest managers to predict how a species will respond to such disturbances or to decide how to manage an area where the water regime has been significantly altered. This paper discusses some factors which influence the waterlogging tolerance of tree species, compiles several classification systems, indicates the pertinent literature, and offers a new relative waterlogging-tolerance rating for southern lowland tree species.
... All four species can tolerate flooding but vary in their tolerance. For instance, overcup oak is most common in wetlands where flooding is restricted to 30-40% of the growing season (e.g., continuous frost-free portion of the year) (Hook 1984) becoming outcompeted by less flood-tolerant species when flooding during the growing season is low (≤29%) and becoming stressed and dying when flooding during the growing season is higher (40-51% and ≥ 52%, respectively) (Hall and Smith 1955). Sweetgum, willow oak and river birch become stressed (34%, 31% and 24%, respectively) and die (43%, 42% and 36%, respectively) at a lower percentage of the growing season inundated than overcup oak (Hall and Smith 1955). ...
... The climate-driven shift in hydrologic regime at Sinking Pond has resulted in a decoupling of regeneration away from adult populations in deep portions of the pond such that no tree species is currently able to recruit new individuals beyond the seedling stage within that large portion of the pond. The four species examined in this study differed greatly in regard to seed size, shade tolerance, sprouting capability and flood tolerance (Hook 1984;Jones et al 1994;Battaglia et al 2004) and these factors all contributed to the interspecies variation in juvenile recruitment failure and adult mortality. ...
... Willow oak produces acorns annually while overcup exhibits masting behavior, producing good seed crops every 2-4 years. Seeds and first year seedlings of both oak species can tolerate prolonged submersion in water (Hook 1984), but continued exposure to flooding with the altered hydrologic regime in Sinking Pond resulted in regular, massive density-independent mortality of seedlings after the first year in the intermediate and deep portions of the pond. An opposite pattern for bottomland hardwood forests was found by Streng et al. (1989) and Jones et al. (1994) who showed that seedling survival of all species significantly increased in the two years after establishment. ...
Regeneration and survival of forested wetlands are affected by environmental variables related to the hydrologic regime. Climate change, specifically alterations to precipitation patterns, may have outsized effects on these forests. In Tennessee, USA, precipitation has increased by 15% since 1960. The goal of our research was to assess the evidence for whether this change in precipitation patterns resulted in shorter growing seasons and recruitment failure in common canopy trees for a forest wetland. In 2001 and 2018, the density of Quercus lyrata (overcup oak), Liquidambar styraciflua (sweetgum), Quercus phellos (willow oak), and Betula nigra (river birch) seedling, sapling and adult density were mapped in an area of 2.3 ha within a seasonally flooded karst depression. Overall, the percentage of the growing season experiencing inundation was 26% greater in the deep than in shallow areas between 2001 and 2018. Saplings and small adults of all four species were restricted to shallow areas, and their abundance has declined substantially. Overcup oak and sweetgum individuals that were recruited into the adult life history stage were repelled from the deep zone. Overcup oak and sweetgum adults experienced lower mortality across the 2.3-ha study area (11% and 26%, respectively) relative to willow oak (56%) and river birch (64%) over the 17-year study. Growing-season inundation showed no relation to mortality in adult sweetgum and willow oak, a positive relation to mortality among adult river birch across size classes and among small adult overcup oak, and an inverse relation to mortality among large adult overcup oak. In shallow regions, overcup oak and sweetgum adults had greater basal area increment relative to the intermediate and deep regions of the pond. Results of hydrologic modeling for the study area, based on rainfall and temperature records covering 1855–2019, show ponding durations after 1970 considerably longer than the historical baseline, across ponding-depth classes. Our results strongly suggest that climate change is a driving factor suppressing tree regeneration since 1970 in this seasonally flooded karst depression.
... Removal of baldcypress has been shown to alter hydrology, sedimentation patterns and ecosystem services such as primary production in freshwater swamps where it is commonly found (Sun et al., 2001). N. aquatica (hereafter water tupelo) is a broadleaf hydrophyte that is very tolerant of deep flooding (Hook, 1984) and is thus widely distributed in coastal and inland wetlands of the southeastern United States. Nyssa sylvatica (hereafter swamp tupelo) is tolerant of prolonged shallow flooding (Hook, 1984) and is found in coastal plain swamps and estuaries in the Southeastern United States, in a similar distribution to water tupelo. ...
... N. aquatica (hereafter water tupelo) is a broadleaf hydrophyte that is very tolerant of deep flooding (Hook, 1984) and is thus widely distributed in coastal and inland wetlands of the southeastern United States. Nyssa sylvatica (hereafter swamp tupelo) is tolerant of prolonged shallow flooding (Hook, 1984) and is found in coastal plain swamps and estuaries in the Southeastern United States, in a similar distribution to water tupelo. Baldcypress, water tupelo and swamp tupelo are all three canopy dominants in southeastern coastal freshwater forested wetlands owing to their high tolerance for flooded conditions (Hook, 1984). ...
... Nyssa sylvatica (hereafter swamp tupelo) is tolerant of prolonged shallow flooding (Hook, 1984) and is found in coastal plain swamps and estuaries in the Southeastern United States, in a similar distribution to water tupelo. Baldcypress, water tupelo and swamp tupelo are all three canopy dominants in southeastern coastal freshwater forested wetlands owing to their high tolerance for flooded conditions (Hook, 1984). L. styraciflua (hereafter sweetgum) is a deciduous hardwood that is native to bottomland areas of the east and southeast portions of the United States. ...
Fog, dew, and cloud‐borne mist are sources of water to vegetation in many ecosystems. The importance of fog as a water source has been documented well beyond ecosystems where plants experience fog for extensive periods over the course of the day (e.g. cloud forests); however relatively little is known regarding the roles of fog and foliar water uptake in ecosystems such as coastal freshwater wetlands that do not experience fog for extensive periods over the course of the day. Coastal freshwater wetland ecosystems lie on the forefront of climate‐change associated stressors that threaten freshwater supplies to vegetation. Considering the potential impact of climate warming on diminishing coastal fog regimes, an improved understanding of the ecophysiological benefits of fog immersion to the vegetation in these ecosystems is critical for understanding the response of these ecosystems to global climate change. Herein, we investigate the potential for foliar water deposition from fog to act as a direct freshwater subsidy to four tree species [Taxodium distichum (L.) Rich., Nyssa aquatica L., Nyssa biflora Walter, and Liquidambar styraciflua L.] that are common in coastal freshwater wetlands. All four species showed the capacity for foliar water uptake across the leaf/needle surface, with a ca. 5‐10% increase in leaf water content after a 3‐hour submersion experiment. Stable isotopes of water provided strong evidence for foliar water uptake in all four species and for bark water uptake in T. distichum after a 24‐hour fogging experiment. Fog exposure also resulted in several ecophysiological benefits to the saplings, including significant improvements in pre‐dawn water status and net photosynthesis.
... Flood tolerance rankings have been created as qualitative descriptions of species' ability to survive a certain depth of flooding over a number of days during the growing season (Bell and Johnson 1974, Teskey and Hinckley 1977, White 1979, Hook 1984. Flood tolerance differs among tree species due to their diverse adaptations in enduring inundation (Kozlowski 1982a, Kozlowski 1982b, Kozlowski 1984, Keddy and Ellis 1985, such as developing adventitious roots to facilitate oxygen diffusion (Teskey and Hinckley 1977). ...
... Soil MS was positively and significantly correlated to elevation (r = 0.186, p = 0.0002) and negatively correlated to cumulative duration of inundation (r = -0.136, p = 0.0064) ( (Bell and Johnson 1974, Teskey and Hinckley 1977, Hook 1984, had much higher average soil MS values (Table 2.5). ...
... Juglans nigra was located in natural areas with high soil MS values, with an average of around 20 x 10 -5 SI , much higher than the soil MS values found in the study area, but due at least in part to the fact that these previous studies had been conducted on Mollisols. However, Quercus palustris did not respond as expected, considering that it has been documented as a moderately flood-tolerant species (Bell and Johnson 1974, Teskey and Hinckley 1977, Hook 1984. Instead, Quercus palustris followed trends similar to Carya illinoensis and Juglans nigra. ...
Flooding is an important determinant of plant establishment, as well as planted tree survival and growth, in restored floodplain forests. Thus, community assembly in a restored floodplain and, ultimately, restoration outcomes are likely constrained by the site’s hydrologic regime, along with other abiotic factors including light availability and the distance from potential colonization sources. However, trees are often planted in restorations without regard to the site’s hydrologic context and do not survive. Therefore, there is a need to understand the relative importance of abiotic factors on tree and herbaceous species establishment and growth, and there is a need for improved tools for identifying critical abiotic factors during pre-restoration planning. In order to determine the effect of hydrology and other abiotic conditions on plant community assembly, I surveyed plant communities within restored floodplain areas of three different ages. I assessed the density and composition of naturally colonizing tree species and the cover of herbaceous-layer plant species. I evaluated the relationship between tree and herbaceous species establishment and light availability, distance from a nearby seed source, elevation and flood regime. In order to determine the effect of hydrology on planted tree survival, I planted 400 bareroot tree seedlings of four commonly planted species along a hydrologic gradient in a recently restored floodplain. I evaluated the effect of exposure to flooding on planted tree survival and growth. I also evaluated the use of soil magnetic susceptibility (MS), a proxy for soil drainage (other factors being equal), as an easily measured, quantitative predictor of planted tree survival and growth. Lower values of soil MS result from long-term reducing (or anaerobic) soil conditions, and so soil MS might provide a guide to match individual tree species with site-specific soil moisture regimes during restoration planning. Despite the presence of an adjacent mature floodplain forest, passive tree seedling colonization in the restored areas was minimal. In the oldest restored area, tree seedling density increased with increasing elevation and decreased with distance from the seed source, suggesting that tree colonization was limited by both flooding and dispersal. The responses of herbaceous understory species composition to site abiotic conditions varied among the three restored areas, but hydrology was the most important predictor of species composition in all areas. In the first year, the overall survival rate of the planted tree seedlings was 55%. After two growing seasons, the overall survival rate was reduced to 24%. Of the four species planted, Quercus bicolor had the highest survival rate, followed by Quercus palustris and Carya illinoensis. None of the Juglans nigra seedlings survived to the end of the study. Elevation, along with time and species identity, were important predictors of planted tree survival; as elevation increased, probability of survival for each of the four species increased. For growth, flood exposure and species identity were the best predictors of changes in planted tree height, whereas planted tree diameter was not well explained by the measured predictor variables. Soil MS was significantly correlated to both total flood duration and elevation. Soil MS was able to predict planted tree survival, with more flood-tolerant species such as Quercus bicolor surviving in areas with a low soil MS reading, corresponding to poorly drained soils. Understanding how tree colonization, planted trees, and herbaceous understory vegetation respond to abiotic factors such as flood duration and distance from colonization sources, as well as developing tools for identifying critical abiotic factors, will allow for more accurate predictions of restoration outcomes and more targeted planting in floodplain restorations.
... laevigata), often cohabitate and are shallowly rooted in wet, floodplain soils [Baker et al., 2001;Kennedy, 1990] but differ in tolerances of flooding and shade. Q. lyrata is highly tolerant of flooding [Hook, 1984] and moderately tolerant of shade [Niinemets and Valladares, 2006], is relatively slow growing, and generally leafs out later than co-occurring species [Solomon, 1990]. C. laevigata is weakly tolerant of flooding [Hook, 1984] and tolerant of shade [Battaglia and Sharitz, 2006]. ...
... Q. lyrata is highly tolerant of flooding [Hook, 1984] and moderately tolerant of shade [Niinemets and Valladares, 2006], is relatively slow growing, and generally leafs out later than co-occurring species [Solomon, 1990]. C. laevigata is weakly tolerant of flooding [Hook, 1984] and tolerant of shade [Battaglia and Sharitz, 2006]. Increasing prevalence of C. laevigata has been observed in floodplains of the region, likely associated with conditions becoming drier from hydrologic modifications that reduce flooding [Gee et al., 2014;Hanberry et al., 2012], which may otherwise kill C. laevigata [Broadfoot and Williston, 1973]. ...
... The effects of dry conditions are noteworthy here because, unlike in upland systems, hydrologic control over wetland ecosystem structure is usually attributed to flooding (e.g., classifications by flood tolerances) [Hook, 1984]. We did not observe direct reductions in J s associated with flooding, possibly because site conditions were never sufficiently hypoxic or the mature trees were resistant to flood stress because of large resource reserves [Waring and Running, 2010]. ...
Hydrologic connectivity provisions water and nutrient subsidies to floodplain wetlands, and may be particularly important in floodplains with seasonal water deficits through its effects on soil moisture. In this study, we measured sapflow in 26 trees of two dominant floodplain forest species (Celtis laevigata and Quercus lyrata) at two hydrologically distinct sites in the lower White River floodplain in Arkansas, USA. Our objective was to investigate how connectivity-driven water table variations affected water use, an indicator of tree function. Meteorological variables (photosynthetically active radiation and vapor pressure deficit) were the dominant controls over water use at both sites; however, water table variations explained some site differences. At the wetter site, highest sapflow rates were during a late-season overbank flooding event, and no flood stress was apparent. At the drier site, sapflow decreased as the water table receded; the late season flood pulse that resulted in flooding at the wetter site did not affect the water table at the drier site; accordingly, higher water use was not observed at the drier site. The species generally associated with wetter conditions (Q. lyrata) was more positively responsive to the flood pulse. Flood water subsidy lengthened the effective growing season, demonstrating ecological implications of hydrologic connectivity for alleviating water deficits that otherwise reduce function in this humid floodplain wetland.
... As the longest-lived tree species in the southeastern USA 39 , T. distichum has been widely used for climate reconstruction by using dendrochronology [40][41][42] . Given the species occupies rivers, floodplains, and swamps, individuals are able to withstand flooding events and moderate amounts of salt intrusion but do not grow in brackish or saline waters 43,44 . Though at such low elevations (<50 m), T. distichum can occur close to coastlines and their mild salt tolerance-compared to other species-allows them to survive modest pulses of saltwater such as storm events 43,44 . ...
... Given the species occupies rivers, floodplains, and swamps, individuals are able to withstand flooding events and moderate amounts of salt intrusion but do not grow in brackish or saline waters 43,44 . Though at such low elevations (<50 m), T. distichum can occur close to coastlines and their mild salt tolerance-compared to other species-allows them to survive modest pulses of saltwater such as storm events 43,44 . On longer time scales, T. distichum is impacted by sea level rise as coastlines shift with marine transgressions and regressions especially on glacial-interglacial time scales when global sea levels fluctuated by ∼125 m 24 . ...
... These species, such as overcup oak (Quercus lyrata) and water hickory (Carya aquatica) are less desirable for waterfowl and timber production (Fredrickson, 1979;Hook, 1984). Red oaks (Quercus spp.), which are of high economic value and desirable for timber harvesting and food (i.e. ...
... Our analysis shows that elevation plays a role in the abundance of nuttall oak and cherrybark oak, but less so for willow oak. As expected, within the lower elevation classes, overcup oak and nuttall oak maintain higher dominance (Fredrickson, 1979;Hook, 1984;Tanner, 1986), and at least for nuttall oak, the model revealed higher abundance of this species within lower elevations of the GTRs. Found alongside nuttall oak and overcup oak within lower elevation classes were water hickory, sugarberry, green ash and elm species. ...
... Overview Plant species vary enormously in flood and drought tolerance physiology, as well as architecture, reproductive strategies, recruitment strategies, and distribution (Malanson 1993;Reichenbacher 1984). As with benthic invertebrates, the wide array of plant adaptive traits has stimulated many attempts to classify and subdivide upland and riparian assemblages into functional guilds (e.g., Cody 1991;Grime 1977;Hook 1984;Johnson et al. 1984) or mapping units. Such efforts may aid in modeling or management, but lifestage differences and the substantial residual noise in such models reveal the diversity of life history strategies required to cope with FRE spatio-temporal non-equilibrium environmental variability. ...
... Subsurface fluvial soil moisture availability also often extends across the floodplain, producing aridland riparian zonation and a transition of vegetation-potentially from gallery riparian forest through xeroriparian woodlands and shrublands, to facultatively riparian upland vegetation, to true upland vegetation. Riparian zonation is less apparent but nonetheless evident in mesic habitats (e.g., Hook 1984), with riparian dominance by bottomland tree species, such as Taxodium distichum (bald cypress), Nyssa aquatica (water tupelo), Larix decidua (larch), Platanus spp. (sycamores), and several Salicaceae species. ...
In the Preface to volume 1, we discuss the development of riparian ecology as one of the newest of ecological fields that gained significant momentum in the 1950s and 1960s as part of the general “riparian movement” in the United States. The field expanded rapidly throughout the latter half of the 1900s. Volume 2 involves more than two dozen authors—most with decades of experience—who expand upon riparian and other topics introduced in volume 1. Two important recent developments are global climate change and impacts of introduced tamarisk leaf beetles (Diorhabda spp.) in the American West. Other chapters in volume 2 that provide current information evaluate the losses of riparian habitat, including “extirpation” of a large number of mesquite bosques (woodlands) in the Southwest; the restoration of riparian ecosystems damaged by anthropogenic activities; the importance of a watershed; and the importance of riparian ecosystems to recreation. The combination of volumes 1 and 2 examines the evolving understanding of scientific implications and anthropogenic threats to those ecosystems from Euro-American settlement of the region to present.
... The main threats for biodiversity conservation are forest invasion by G. triacanthos and fluvial bank erosion (DINAMA, 2014). The area of study is also subject to a persistent flood regime that could affect the survival and dispersion of seeds (Hook, 1984). ...
... This species tolerates a wide range of environmental conditions (USDA, 2017). But it has a moderate tolerance to waterlogging; in fact saplings of G. triacanthos were killed or retarded by 105 days of flooding (Hook, 1984). Besides, its frequency of regeneration beneath closed canopy is low (Grime and Source, 1965). ...
Enlace descarga pdf completo hasta 29 marzo 2018: https://authors.elsevier.com/c/1WWr81L~GwCrnH
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Exotic species have different strategies to invade a new area. Invasive species limited by establishment have a wide dispersion range and high seedling mortality rate. Riparian forests are harsh environments for the establishment of plants. In this sense, we tested the hypothesis that the invasive process of G. triacanthos is limited by establishment in a riparian forest of the Uruguay River and that it begins in the fluvial bank at the transition zone between forest and grassland and moves towards the shore border. We expected that: (1) the distribution pattern of adults of G. triacanthos would be decoupled from the distribution pattern of seedlings and saplings (prereproductive stages); (2) the population would have a cluster distribution pattern related to the occurrence of punctual events that favoured the development to adult stages; and (3) the abundance of seedlings, saplings and adults would be higher in the transition zone (between forest and grassland) than in the shore border of the fluvial bank. The spatial pattern of G. triacanthos along the Uruguay River was analyzed using spatial point pattern analysis: autocorrelation indexes, hot spots and wavelet analysis. The effect of the fluvial bank position on the abundance of G. triacanthos was evaluated using non-metric multidimensional scaling (NMDS). This methodology allowed us to detect a primary invasion area, an invasion focus and the dispersal area. This pattern corresponded to an infiltration invasion pattern limited by establishment. It did not seem to be affected by position in the fluvial bank. This information could be relevant to establish correct decision-making in the control of an invasive process and provide an applicable methodology for any other invasion process, especially in riparian ecosystems.
... Most of the area in this site was relatively dry during spring and summer and therefore R s was higher, while heavy rains in the autumn raised the water table and submerged most of the area (Fig. 2d), decreasing the R s . Even though the root systems of most flood-tolerant plants remain active when flooded (Angelov et al., 1996;Hook, 1984;Keeland et al., 1997;Mancuso and Shabala, 2010), standing surface water also impeded the diffusion of CO 2 from belowground resulting in low observed R s . For example, in September 2010 when soil temperature was similar to June, R s responded immediately to flooding and decreased to 1.8 ± 1.2 (mean ± SE) g CO 2 -C m −2 d −1 , whereas the rate was 8.1 ± 1.8 g CO 2 -C m −2 d −1 in June (Fig. 5b). ...
... The weakly defined hysteresis in R agp suggests that plant physiological activity was less affected by hydrologic regimes (Fig. 5c), arguably due to the adaptations of the dominant species to flooding. Although R agp was indirectly calculated in this study, the high flooding tolerance of the dominant species, such as swamp tupelo, Atlantic white cedar and swamp cypress who have pneumatophores, root structures with large air-filled cells that protrude from ground and are hypothesized to facilitate gas exchange between the atmosphere and submerged roots, lends credibility to the adaptation hypothesis (Angelov et al., 1996;Hook, 1984). Gravatt and Kirby (1998) also reported that short-term (e.g. ...
Wetlands store a disproportionately large fraction of organic carbon relative to their areal coverage, and thus play an important role in global climate mitigation. As destabilization of these stores through land use or environmental change represents a significant climate feedback, it is important to understand the functional regulation of respiratory processes that catabolize them. In this study, we established an eddy covariance flux tower project in a coastal plain forested wetland in North Carolina, USA, and measured total ecosystem respiration (Re) over three years (2009–2011). We evaluated the magnitude and variability of three respiration components – belowground (Rs), coarse woody debris (RCWD), and aboveground plant (Ragp) respiration at the ecosystem scale, by accounting microtopographic variation for upscaling and constraining the mass balance with Re. Strong hydrologic control was detected for Rs and RCWD, whereas Ragp and Re were relatively insensitive to water table fluctuations. In a relatively dry year (2010), this forested wetland respired a total of about 2000 g CO2-C m⁻² y⁻¹ annually, 51% as Rs, 37% as Ragp, and 12% as RCWD. During non-flooded periods Rs contributed up to 57% of Re and during flooded periods Ragp contributed up to 69%. The contribution of Rs to Re increased by 2.4% for every cm of decrease in water level at intermediate water table level, and was nearly constant when flooded or when the water level more than 15 cm below ground. The contrasting sensitivity of different respiration components highlights the need for explicit consideration of this dynamic in ecosystem and Earth System Models.
... Qualitative flood tolerance rankings have been used to describe species' ability to survive a certain depth of flooding over a number of days (Bell and Johnson, 1974;Teskey and Hinckley, 1977;Hook, 1984). Flood tolerance differs among species because of their diverse adaptations for enduring inundation (Kozlowski, 1982a(Kozlowski, ,b, 1984Keddy and Ellis, 1985), such as developing adventitious roots to facilitate oxygen diffusion (Teskey and Hinckley, 1977). ...
... K.Koch, Carya laciniosa (Mill.) K.Koch, Carya tomentosa Sarg., and Quercus alba L., which have similar flood tolerance ratings to C. illinoensis and J. nigra (Bell and Johnson, 1974;Teskey and Hinckley, 1977;Hook, 1984), had higher average soil MS values (Table 4). ...
Flooding in floodplain forests is an important abiotic constraint on tree recruitment, as well as on planted tree survival and growth in restorations. Nevertheless, trees are often planted in floodplain restorations without regard to a site’s hydrologic context, resulting in poor survival. There is a need for improved tools for identifying critical abiotic factors that control tree growth and mortality at reforestation sites. We planted 400 bareroot tree seedlings of four commonly planted species in plots along five 100-m transects along a hydrologic gradient in a recently restored wetland to determine the effect of hydrology on planted tree survival. We evaluated the effect of exposure to flooding on survival and growth for two growing seasons. We also evaluated the use of soil magnetic susceptibility (MS) as a proxy for soil drainage and predictor of tree survival and growth. Soil MS is easily measured and mainly reflects the concentrations of ferrimagnetic minerals, which can dissolve with iron reduction in poorly drained soils. In the first year, the overall survival rate of the planted seedlings was 61%. By the end of the study period, survival had declined to 25%. Of the four species planted, Quercus bicolor survived best, followed by Quercus palustris and Carya illinoensis. No Juglans nigra seedlings survived to the end of the study. Duration of inundation and species identity were important predictors of growth and survival; as duration of inundation increased, height growth and probability of survival for each species decreased. Soil MS was not strongly correlated with either flood duration or elevation and was not an effective predictor of tree survival at this site, but might be a useful tool to guide planting in areas with a more pronounced hydrologic gradient. This research can help provide higher precision tree planting in accordance with species’ natural distribution across soil moisture gradients, ultimately leading to greater planting success in restorations.
... Sugarberry is a shade-tolerant species that is also shallow rooted on wet sites (Kennedy 1990). In a review of species tolerances to water logging, Hook (1984) classified overcup oak as 'highly tolerant' and sugarberry as 'weakly tolerant.' ...
... Species differences in growth timing suggest differences in their response to environmental conditions, which may affect species interactions and community changes. While sugarberry has been classified as 'weakly flood tolerant' and overcup oak as 'highly flood tolerant', based on their typical zonation (Hook 1984), our results suggest that these classifications oversimplify their habits. Further testing is needed, but because the majority of sugarberry growth occurred in the early portion of the season, they showed tolerance to deep flooding in our study year. ...
... We tested the time to mortality under intensifying drought conditions for seedlings of three common swamp species (water tupelo, Ogeechee tupelo, and pop ash) and two common Loblh species (overcup oak and water hickory) of the Apalachicola River floodplain. On a scale of flood tolerance increasing from 1 to 5, the chosen swamp species were rated as 5 and the Loblh species were rated as 4 (Hook 1984;McKnight et al. 1981). Our research questions were (1) does drought stress cause faster mortality of swamp species than neighboring Loblh species, and (2) what thresholds of soil moisture and duration cause mortality of these species? ...
Anthropogenic and climatic variables combine to alter river flow regimes worldwide, which can influence shifts in species composition. Exacerbation of drought events in southeastern United States floodplains may have varying impacts on survival and regeneration of high bottomland, low bottomland, and swamp forest species, causing distribution shifts between these forest types. We tested 7-month-old seedlings of the swamp species water tupelo (Nyssa aquatica), Ogeechee tupelo (Nyssa ogeche), and pop ash (Fraxinus caroliniana), and the low bottomland species overcup oak (Quercus lyrata) and water hickory (Carya aquatica) in a controlled experiment with increasing drought treatment. We compared timing to 95% mortality and determined lethal soil moisture thresholds for species. Swamp species were no more vulnerable to mortality under increasing drought than low bottomland hardwood species found in neighboring wet floodplain habitats, suggesting that duration of drought may not be a main driver of compositional shifts between these forests.
Study Implications: Natural flows of river systems around the world have been altered by humans and a changing climate. Increased intensity of drought events can affect tree species growing adjacent to rivers and influence their ability to reproduce, thus changing the composition of floodplain forests. We tested the drought tolerance of three swamp species accustomed to frequent flooding and two low bottomland hardwood species accustomed to less frequent flooding to see which species might be more affected by drought. We observed no differences between these two groups, suggesting that greater flood tolerance may not imply greater drought intolerance.
... Some studies have suggested that sustained waterlogging led to adventitious root formation in waterlogged plants and thus, improving oxygen availability in root system [16]. Morphological adaptive traits observed under the stimulus of prolonged waterlogging are, increased survival of secondary roots, emergence of secondary roots designated as soil water roots and physiologically, increased metabolism and aerobic respiration rates in the roots [17]. ...
Flooding has become a common occurrence due to climate change leading to prolonged water-logging which suffocates plant rooting, thus reduced growth, yield or total loss. Limited research has been conducted on the same. This study is aimed at investigating the effect of flooding period on the early growth of Grevillea robusta nursery seedlings in Njoro, Kenya. An experiment was set up for 2 months in Egerton University Agroforestry tree nursery using a six months old Grevillea seedlings. Completely randomized block design (RCBD) with 4 treatments replicated 3 times was used. The treatments were: Non-flooding, 2 days flooding, 4 days flooding and 6 days flooding. Data was collected for shoot, foliage and root variables and analyzed using SAS statistical package while means were separated using least significance difference (LSD). Non-flooding recorded the highest performance for all the shoot and foliage variables while the least was 2 days flooding. On the other hand, 6 days flooding was the second in performance for most of the variables especially 3rd internode length (20.2 mm) and fresh shoot biomass (56.4 g) were significantly (P=0.002 and 0.05) higher respectively compared with 2 days flooding (13.5 mm and 46.7 g) respectively. In conclusion, flooding affects the growth of Grevillea seedlings negatively by reducing their growth and this was more pronounced in 2 days flooding. However, for 6 days flooding, the seedlings seem to adjust through development of adaptive strategies in the roots. Further research needs to be conducted on other species and also prolonged flooding period.
... However, species such as Nuttall oak, that can quickly recover photosynthesis after a short-term flood (Anderson and Pezeshki 2000;Pezeshki and Anderson 1997), are at an advantage over those that are slower to recover (Gong et al. 2007;Pezeshki et al. 1996;Renninger et al. 2020). The physiological effects of flooding on Shumard oak have been less well studied, but Shumard oak is expected to have decreased height growth and decreased survival when flooded during the growing season compared with Nuttall oak (Hook 1984;Jacques et al. 2021). If seedlings are allowed the chance to recover once a flood subsides, the chance of survival increases (Bratkovich et al. 1994). ...
Key message
Whereas Shumard oak seedlings are intolerant of dormant season flood, Nuttall oak seedlings are tolerant. Flooding more than 1–2 months beyond budbreak may have persistent negative impacts on Nuttall oaks.
Abstract
Since flooding in winter and spring is an integral part of bottomland hardwood ecosystems in the southeastern United States, moderately flood-tolerant oaks, like Nuttall oak (Quercus texana), should be well adapted to flooding during these seasons. To quantify the potential for injury from different lengths of winter flooding, we flooded seedlings of Nuttall oak and moderately flood intolerant Shumard oak (Q. shumardii) for 0, 1, 2, and 3 months, with the first month of flooding occurring during the dormant season. Flooding during dormancy had no effect on Nuttall oak, but Shumard oak seedlings had reduced growth in the spring. Flooding that extended beyond budbreak resulted in reduced leaf area and root biomass accumulation in spring for both species, while Shumard oaks also experienced high mortality. At the end of the growing season, Nuttall oaks that had been flooded accumulated tissue biomasses similar to non-flooded seedlings, except taproot biomass, which was reduced 40% by 3 months of flooding. It appears that Nuttall oak delayed fully investing in spring growth until after flooding subsided, and then was largely able to compensate following flooding that extended one month beyond budbreak. However, flooded Shumard oaks did not show similar signs of recovery. Thus, sites that flood at any time of year would not be suitable for Shumard oak. Our results suggest that natural or human-imposed flooding can extend several weeks beyond budbreak without harming Nuttall oaks, but inundation prolonged several months beyond budbreak could weaken the ability to respond to subsequent stresses.
... It has a tolerance to a wide range of environmental conditions (USDA 2017). However, it shows moderate tolerance to ooding, (Hook 1984) and low regeneration when canopy is dense (Grime 1965). Its invasive potential is high; it has asexual and sexual reproduction, a high rate of fructi cation, seed production and germination and short juvenile stages (Marco and Páez 2000). ...
Riparian systems are highly threatened by alterations in its hydrological regimen and biological invasions. To guide its conservation is important to understand the relationships established between biological invasions and abiotic conditions affected by the hydrological regimen. We analyze the relationship between the distribution pattern of soil sand content and the invasive process of the woody invasive Gleditsia triacanthos in riparian forests of the Esteros de Farrapos and Islands of Uruguay River National Park, zoning the study area according to the type of relationship between both variables. We integrate the use of regression trees and geographic information systems to zone this relationship. This is a novel approach to study the relationships between an invasive species and its environment. Areas with lower sand content were found to be favorable for the development of the invasive species, and areas with higher sand content were found to limit its spread. No relationship was found between the intermediate sand content and the progress of the invasive process. This work highlights the complexity inherent to the definition of causal relationships in highly heterogeneous systems such as riparian ecosystems. Spatial analysis techniques are a useful tool for this approach.
... Tolera un amplio rango de condiciones ambientales (USDA, 2017). Sin embargo presenta moderada tolerancia a la inundación, (Hook, 1984) y baja regeneración cuando el canopeo es denso (Grime, 1965). Su potencial invasivo es alto; presenta reproducción asexual y sexual tiene una alta tasa de fructificación, producción de semillas y germinación y estadios juveniles cortos (Marco and Páez, 2000). ...
Los ecosistemas fluviales presentan alta vulnerabilidad. Su degradación se asocia fundamentalmente a alteraciones del régimen hídrico afectando la deposición y consecuentemente las condiciones edáficas determinantes del establecimiento de la vegetación pudiendo afectar procesos invasivos de especies vegetales reconocidos como otra importante amenaza. Por tanto, resulta relevante comprender la relación entre las condiciones edáficas y los procesos invasivos. Este trabajo evalúa la relación entre el contenido de arena y la distribución de la leñosa invasora Gleditsia triacanthos en un bosque del Río Uruguay. Se caracterizó el patrón espacial de la variación en la textura del suelo, el patrón de distribución de G.triacanthos y las relaciones existentes entre éste y el contenido de arena del suelo. Se detectó variación en la textura del suelo en el eje norte-sur y en el eje este-oeste. Se detectó una relación compleja entre la abundancia de G.triacanthos y el contenido de arena del suelo.
... Other studies have evaluated seedlings of many other taxa and noted significant differences in their ability to survive flooding of different durations. Hook (1984) rated a number of species in terms of "waterlogging [of the soil] tolerance" and placed them on a spectrum from most tolerant (for example, baldcypress and water tupelo) to highly Figure 8-A debris jam that accumulated in the riparian forest along this river consists of trees that succumbed to bank undercutting or other toppling processes (e.g., windthrow) that placed the downed wood in the river. This flotsam can be hurled against bankside trees with considerable force during flood events, sometimes injuring or toppling other standing timber. ...
Forests in the Southern United States experience a wide variety of weather-related disturbances, from small-scale events which have management implications for one or a few landowners to major hurricanes impacting many ownerships across multiple States. The immediate impacts of catastrophic weather disturbance are obvious-trees are killed, stressed, or damaged due to wind, flooding, ice, hail, or some combination of events. How forests respond to disturbance depends on several factors such as forest types and attributes, ecoregion, local pressure from invasive plants, preexisting infestations of pests and pathogens, prior disturbance events, and other variables which interact in complex ways, influencing successional dynamics and management decisions. In this review, we synthesize the major weather perturbations affecting the forests of the Southern United States and current state of the knowledge surrounding interactions between these events, forest pests, and forest diseases. We present a compilation of non-quantitative observations between 1955 and 2018 from annual U.S. Department of Agriculture Forest Service "Major Forest Insect and Disease Conditions in the United States" reports describing where insects or diseases were found on trees that were stressed by weather disturbances. Two conceptual models are presented, one describing changes in forest structure and composition, and a generalized model of herbivorous pest population fluctuations following different severity levels of disturbance. Finally, we propose 11 questions that require additional research to better inform sustainable forest management decisions in preparation for and in response to catastrophic weather events.
... This is probably due to the overall larger dimensions. The idea is derived from the fact that big mature trees are not so heavily impacted by temporary water-logging in comparison to small (young) trees (HOOK 1984). ...
The thesis is aimed at the verification of the use of large-sized planting stock on mid-elevation sites as a contribution to the regeneration and transformation of forest stands to reach the stability and diversity of forests. The goal is primarily to test the suitability of new generation saplings and semi-saplings (NGSS) of deciduous tree species on selected experimental plots for this purpose. The work analyses and summarizes the outcomes of several field experiments focused on testing the large-sized planting stock on mid-elevation sites. Mortality, growth and other characteristics of NGSS on selected research sites were evaluated.
NGSS is characterized by an advanced, rich and compact root system and an improved ratio of aboveground and underground biomass to standard planting material, as well as generally larger dimensions.
The basic hypothesis was that the NGSS show better growth dynamics on (exposed and extreme) habitats. The research was done on the basis of the evaluation of older research experimental plots, but new plots were also established. Additional analyses included the application of brassinosteroids onto advanced planting stock during the post-planting period, analyses of the chlorophyll content of NGSS and standard planting stock, and the determination of aboveground and underground biomass volumes in the tested planting stock types.
New generation saplings and semi-saplings showed generally better increments in both height and root collar diameter as well as improved vitality. This was confirmed on various types of habitats. Therefore, this type of planting stock is recommended for reforestation and afforestation in specific and difficult cases, considering its higher costs.
Basic economic analysis and evaluation of the economic efficiency of using the NGSS system is a part of the work. With different combinations of the number of planted trees and mowing regimes, the economic endurance of the NGSS system can be achieved thanks to the better attractiveness and vitality of the NGSS.
... Tolera un amplio rango de condiciones ambientales (USDA, 2017). Sin embargo presenta moderada tolerancia a la inundación, (Hook, 1984) y baja regeneración cuando el canopeo es denso (Grime, 1965). Su potencial invasivo es alto; presenta reproducción asexual y sexual tiene una alta tasa de fructificación, producción de semillas y germinación y estadios juveniles cortos (Marco and Páez, 2000). ...
SOSA, B.; FERNÁNDEZ, G.; ACHKAR, M. Relación entre la propagación del proceso invasivo de gleditsia triacanthos y la deposición de arena en bosques del Río Uruguay. GeoUECE (online), v. 09, n. 16, p. 110-122, 2020.
... Nonetheless, prolonged flooding waterlogs soil, which results in low oxygen levels in roots. Trees in flooded habitats with long hydroperiods thus are chronically stressed (Whitlow and Harris 1979, Hook 1984, Kozlowski et al. 1991. Similar stresses are less pronounced for graminoids in flooded habitats because their roots contain more airspace (Kercher and Zedler 2004) or aeration of roots can occur as long as parts of live or dead culms remain above water level (as for example, Cladium jamaicense; Conway 1936, Loveless 1959, Steward and Ornes 1975, Herndon et al. 1991, Urban et al. 1993, Newman et al. 1996, Sorrell et al. 2000. ...
Historically, pine savannas characterized landscapes across the Gulf Coastal Region, including most of Florida. Treeless habitats (historically called "prairies") also occurred as lowland inclusions in savanna landscapes. What restricted trees from prairies? We develop a conceptual model that is based on prior models of prairie-forest landscapes. We use predicted relationships between trees and graminoids to explore how fire and seasonal flooding might influence the continuum from closed-canopy forests to open-canopied savannas to treeless prairies. The starting model predicts community position along this continuum as a function of fire frequency. We then modify this conceptual model to include evolutionary adaptations of trees that result in survival of frequent, low-intensity fires. Finally, we modify it to incorporate postulated interactive effects of fire and seasonal flooding on trees and graminoids. This model may be useful in predicting characteristics of savanna-prairie mosaics in the southeastern United States. We apply this model to the dry prairie landscape of central Florida. We examine two regions with pine flatwoods and dry prairies: Myakka River State Park (Sarasota and Manatee Counties) close to the Gulf coast and Avon Park Air Force Range (Polk and Highlands Counties) in the interior of the peninsula. For these two regions we compare local climatic conditions predicted to facilitate the occurrence of pine flatwoods and dry prairie. Specifically, we compare the conditions likely to result in lightning fires in the two regions and compare those with the likelihood of post-fire flooding in pine flatwoods and dry prairies in each of the two regions. These climatic patterns indicate a close temporal association of fires and flooding during the summer growing season at both sites. The increase in frequency of lightning strikes in April-June occurs at the same time that the mean rain-free interval reaches a maximum and the mean ground water levels reach a minimum. Thus, large fires in the landscape are expected at this time. Within a few weeks the frequency of thunderstorms increases, resulting in frequent rains. Rapid increases in mean water levels saturate the soil. Consequently, early lightning season fires are followed soon by flooding. Thus, environmental conditions predicted not to favor trees occur seasonally in dry prairie landscapes. We anticipate that subtle differences in the likelihood of surface soil saturation will influence survival of trees, resulting in prairie inclusions in the pine flatwoods landscapes of central Florida.
... Slopes of peaks of low flow before the storm (September 10) are included . these timber types are tolerant of short-term flooding (Hook, 1984), so flooding resulted in very little loss in timber value. The interaction of the ocean, estuary, and tidal river is the least understood aspect of coastal hydrology (Ensign et al. 2012). ...
This paper examines data from 18 USGS gauges in the lower Pee Dee Basin in an effort to explain the behavior of the flooding following Hurricane Florence (2018) in Georgetown County, South Carolina. Despite record or near-record flooding in all the tributaries to the Winyah Bay estuary, water levels near the city of Georgetown were well below predicted heights. Floodplain storage in the lower Great Pee Dee, Lynches, and Little Pee Dee River valleys stored over 1.2 million acre-feet of floodwaters, delaying peak stage near Bucksport for five days and reducing peak flow into the Winyah Bay tidal river/estuary system by nearly 50%. An unknown amount of flow from the Winyah Bay tidal river/estuary system flowed through the Atlantic Intracoastal Water Way to Little River rather than through Winyah Bay. The resulting freshwater flow to Winyah Bay only moved the point of tidal stagnation (where upstream tidal flow balances downstream freshwater flow) to near Georgetown. Since the city of Georgetown was near the point of stagnation, water level there was driven by ocean tidal height rather than river flood stage. The lack of discharge data from the tidal rivers in Georgetown County prevents evaluation of the importance of each of these factors and will limit efforts to make quantitative predictions of future flooding in the county.
... A wetland's hydroperiod (flood frequency, duration, depth, and timing) determines which species will germinate, become established, and persist in a given wetland area. Seeds of bald cypress and water tupelo, two of the most flood-tolerant trees found in tidal freshwater forested wetlands (Hook 1984), do not germinate in continuously flooded soils (DuBarry 1963). Increased flooding and extended waterlogging result in decreased photosynthesis (McLeod et al. 1996) and growth (Pezeshki et al. 1987;Young et al. 1995), with eventual mortality to those species that are less flood tolerant (Harms et al. 1980). ...
Tidally influenced coastal forested wetlands can be divided into two broad categories, mangroves and freshwater forested wetlands. These forested wetlands perform valuable ecosystem services, and both are endangered by threats of sea level rise and land use. Understanding the mechanisms that control the distribution of tidal forests has been greatly enhanced by innovation in measurement and modeling of tidal forcing brought about by satellite observation of sea level. Oceanographic hydrodynamic models can now be merged with riverine hydraulic models to address forcing functions in the upper estuary and tidal river. There are new opportunities to study these unique forested ecosystems in a context of (a) the physical driving mechanisms that control their distribution and (b) the anthropogenic and natural disturbances that impact these ecosystems. Remote sensing and geographic information system technology and hydrodynamic, hydraulic, and hydrologic modeling can and must be combined to understand the functioning of these dynamic systems and their interactions with the environment. This chapter summarizes the tidal process and ecosystem characteristics of tidal forested wetlands, with examples from eastern China and the Southeastern United States. The first example demonstrates the need for hydrodynamic modeling to correctly interpret a time series of satellite images in order to evaluate the impact of human management on tidal wetlands. The second examines both empirical data on tidal dynamics and geospatial modeling to examine effects of sea level rise on freshwater forested wetlands. A short review of two widely used large-scale hydrologic models is also provided for describing the flow transport in intertidal rivers, a transition between tidal estuaries and freshwater nontidal wetlands.
... Briefly, trees may suffer physical damage like abrasion or become uprooted during energetically intense flows (Sigafoos 1964, Karrenberg et al. 2003. Physiological stress can arise due to rootzone saturation (Hook 1984, Hook and Brown 1973, Blom & Voesenek 1996, Kozlowski 1984 or overtopping of end shoots (Stanturf and Gardiner 2000) and can interfere with growth and regenerative processes often in complex ways (Gee et al. 2014, Battaglia et al. 2000, Jones et al. 1994, Kroschel et al. 2016, Hosner and Minckler 1963. Further, phenology of different species can interact with the timing and magnitude of inundation to alter germination success (Streng et al. 1989) and mortality rates of different sizes and age classes. ...
... In minimally modified floodplains, the interrelations among geomorphic features, soils, and hydrology control tree species distributions and form the foundation for BLH forestry (Putnam et al. 1960, Wharton et al. 1982, Hodges 1994. In the face of the bewildering complexity that results, the first generation of BLH management tools tended to simplify these interrelations, using the most obviously relevant characteristic of the site: growing-season flood duration (Bedinger 1971, Hook 1984. Describing the distribution of BLH tree species in terms of flood zones provided a clear and concise concept to guide land-management decisions (Larson et al. 1981). ...
Bottomland hardwoods are floodplain forests along rivers and streams throughout the southeastern United States. The interrelations among hydrology, soils, geomorphic landforms, and tree species composition are the foundation of forest management in bottomland hardwoods, and historically their correspondence has allowed for somewhat predictable forest responses based upon the hydrogeomorphic setting. However, extensive hydrologic and geomorphic modifications in floodplains have disrupted these interrelations and, on many sites, have created novel disturbance regimes resulting in unpredictable forest responses. Reduced or altered timing of surface flooding and groundwater declines are common in the region and have favored increases in stem densities, particularly of species less tolerant of flooding and more tolerant of shade. In these highly modified systems, more process-level understanding of floodplain hydrology, soil moisture dynamics, interspecific tree competition, and regeneration is needed to develop more effective management prescriptions and for forestry to be represented in integrated water-resource management decisions.
... De hecho, las plántulas representaron el 93% del total de individuos registrados mientras que los adultos y juveniles representaron el 5% y el 2% respectivamente. La baja tolerancia a la inundación de las plántulas de G. triacanthos (Hook 1984) podrían explicar este patrón. El pastoreo por ganado también podría limitar su desarrollo. ...
El libro presenta más de 20 trabajos sobre la ecología del bosque nativo de Uruguay, que abordan aspectos de la dendrocronología, distribución, diversidad, sucesión, restauración e invasiones biológicas.
... With the restoration of historical hydrology, several areas within the site that were not previously farmed converted into ghost forest landscapes ( Fig. 2a and b), as flood-intolerant species (e.g. Acer rubrum L.) succumbed most likely to the stress associated with living in a permanently inundated environment (Hook 1984b;Kozlowski 1997). To date, living trees persist, but are restricted to either flood-tolerant species such as Taxodium distichum (L.) Rich., Nyssa aquatica L., Nyssa sylvatica Marshall var. ...
In vegetated wetland ecosystems, plants can be a dominant pathway in the atmospheric flux of methane, a potent greenhouse gas. Although the roles of herbaceous vegetation and live woody vegetation in this flux have been established, the role of dead woody vegetation is not yet known. In a restored wetland of North Carolina’s coastal plain, static flux chambers were deployed at two heights on standing dead trees to determine if these structures acted as a conduit for methane emissions. Methane fluxes to the atmosphere were measured in five of the chambers, with a mean flux of 0.4 ± 0.1 mg m⁻² h⁻¹. Methane consumption was also measured in three of the chambers, with a mean flux of −0.6 ± 0.3 mg m⁻² h⁻¹. Standing dead trees were also a source of the flux of CO2 (114.6 ± 23.8 mg m⁻² h⁻¹) to the atmosphere. Results confirm that standing dead trees represent a conduit for the atmospheric flux of carbon gases from wetlands. However, several questions remain regarding the ultimate source of these carbon gases, the controls on the magnitude and direction of this flux, the mechanisms that induce this flux, and the importance of this pathway relative to other sources at the landscape level.
... At Wilson Creek, we observed significant natural colonization of P. occidentalis seedlings alongside planted seedlings. The lack of available sunlight due to the spacing of our plantings (Clatterbuck et al. 1987, Oliver et al. 1990) and rapid growth of P. occidentalis seedlings (planted and naturally colonized), in combination with continual flooding (Hook 1984), and high soil pH (Stanturf et al. 2004), likely contributed to the low survival of Q. palustris seedlings and the stunted height growth of F. pennsylvanica seedlings at our site. While deer browse activity on planted seedlings is a common concern (Rooney and Waller 2003), we did not observe extensive browse activity on any of our three tree species; however beaver activity on our planted sycamore seedlings was observed and lead to extensive resprouting, adding to the shading pressure on Q. palustris seedlings. ...
Degradation, impoundment, and channelization of streams is a global problem. Although stream restoration projects have increased in recent years, post-restoration, long-term monitoring is rare. In 2003, a channelized section of Wilson Creek (Nelson Co., Kentucky) was restored by creating a meandering channel, reconnecting the channel to its floodplain, and planting native riparian species: giant cane and bottomland forest species. Our main objective was to conduct a ten-year post-restoration assessment to determine long-term restoration outcomes of channel water quality, growth of trees planted in the riparian area, and soil development. Water quality, soil, and tree data collected in 2013–2015 was compared to 2004–2006 data. Quality of water parameters changed over time: sulfate, magnesium, calcium, potassium , alkalinity, pH, iron, and temperature decreased, whereas dissolved oxygen increased. Overall, soil pH, extractable ammonium, extractable nitrate, total carbon (TC), and total nitrogen (TN) increased over time. Effects were observed in restored riparian areas for pH, extractable ammonium, and TC; while TC and TN exhibited depth-dependent interactions. The carbon-nitrogen ratio in these soils significantly decreased over time for the reference sites, and the treatments recovered to near reference level. Platanus occidentalis (American sycamore) and Fraxinus pennsylvanica (green ash) individuals had higher survival (80% and 79%, respectively) than individuals of Quercus palustris (pin oak; 22%). Shelter and herbicide treatments had no effect on tree survival or height growth; however, height growth varied by species. Platanus occidentalis exhibited a greater than five-fold increase, F. pennsylvanica slightly increased, and Q. palustris decreased in height growth. Overall, water and soil quality improved over time at the restoration site, while tree survival and height growth exhibited species-specific outcomes.
... Early logging effectively eliminated all of the old growth cypress forests in the southeastern United States, and most extant sites today are secondary growth. The earliest research on the species primarily focused on its ecology, seeking to understand basic trends in net primary productivity, biomass, and nutrient cycling within bald cypress forests (Schlesinger 1978), as well as the tolerance of the species to flooding (Hook 1984a(Hook , 1984bMcLeod et al. 1986;Megonigal and Day 1992;Kludze et al. 1994;Megonigal et al. 1997). However, recent trends in research are more applied, seeking to understand the response of this foundational species (Ellison et al. 2005) to changes in water chemistry associated with climate change concerns such as sea level rise, surface and subsurface saltwater incursion, and extreme episodic events (Allen et al. , 1996(Allen et al. , 1997Conner et al. 1997;Krauss et al. 1999Krauss et al. , 2007Conner and Inabinette 2005;Doyle et al. 2007). ...
Wetland restoration is a common practice in the southeastern United States, where changing land use patterns have resulted in the widespread degradation of coastal ecosystems. Re-establishment of indigenous vegetation is a fundamental paradigm of restoration practice. In freshwater wetlands, this often includes planting flood-tolerant species such as Taxodium distichum (L.) Rich (bald cypress). While much is known regarding the ecology of this foundational species, research establishing the ecophysiological profile of mature bald cypress under stress-free, baseline conditions is limited. Therefore, a study was undertaken in 2015 to monitor the growing season ecophysiology of a bald cypress stand in a restored coastal wetland. Net photosynthesis was constant in the early to mid-growing season, declining steadily late in the growth season until the visible onset of needle senescence. Patterns in transpiration matched those observed for photosynthesis, whereas needle conductance and chlorophyll fluorescence appeared to track expected patterns associated with needle development. Trees at this site appeared healthy and were reproductively competent. However, long-term monitoring of the stand would help evaluate the ecological sustainability of this restoration project. We advocate for the inclusion of ecophysiological-based vegetation monitoring within restoration projects, enabling a sensitive and early indication of the trajectory of a restoration plan.
... When the water level becomes too low, as for instance during droughts, the 33 hydrological connection between river and floodplain is lost. In these periods, the ground is 34 exposed more frequently, soil moisture tends to evaporate more easily, thus affecting (Hook, 1984). As the flood depth in the swamp becomes deeper and the water 142 stagnant, the two species occupy much of the same area (Johnson, 1965 ...
The distribution of swamp floodplain vegetation and its evolution in the lower non-tidal reaches of the Apalachicola River, Florida USA, is mapped using Landsat Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images captured over a period of 29 years. A newly developed seasonality index (SI), the ratio of the NDVI in winter months to the summer months, shows that the hardwood swamp, dominated by bald cypress and water tupelo, is slowly replaced by bottomland hardwood forest. This forest shift is driven by lower water levels in the Apalachicola River in the last 30 years, and predominantly occurs in the transitional area between low floodplains and high river banks. A negative correlation between maximum summer NDVI and water levels in winter suggests the growth of more vigorous vegetation in the vicinity of sloughs during years with low river flow. A negative correlation with SI further indicates that these vegetation patches are possibly replaced by species typical of drier floodplain conditions.
Riparian forests are among the most vulnerable ecosystems to biological invasions. Effective management
strategies require a nuanced understanding of both species invasiveness and environmental conditions, but
analysing these interactions is complex. We designed an Agent-Based Model (ABM) to simulate the spatio-
temporal spread of Gleditsia triacanthos in the riparian forest of the Esteros de Farrapos e Islas del Río
Uruguay National Park; Uruguay. This is a parsimonious and generalisable model that incorporates distinctive
features of woody invasions in riparian systems—such as environmental heterogeneity and flooding regimes—as
well as common characteristics of woody invaders. Management simulations suggest that if control measures are
maintained over time, the abundance of the invader will remain constant at low levels; thus, the invasion can be
controlled, even if not completely eradicated. The results also indicate that without control, the invasion process
would spread even into unsuitable areas. The SWIRS model facilitates the evaluation of targeted management
strategies, ultimately providing a framework to enhance biodiversity conservation efforts in riparian ecosystems.
Ecosystem structure of wetlands in managed floodplains depends on hydrological processes controlled by geomorphology and water management. Overlapping effects of direct modifications and geomorphic adjustments to management can combine to trigger changes to floodplain ecosystem structure. We examined the case of woody vegetation encroaching into the depressional Catahoula Lake, Louisiana, in the context of regional hydrologic and geomorphic modification in the floodplain of the Mississippi River. Historical aerial photos indicated woody encroachment into Catahoula Lake for at least 80 years, and the rate of expansion has increased in recent decades. Historical stage analysis revealed that the downstream Red‐Atchafalaya‐Mississippi river system controls the lower limit of the lake water level when the large rivers are high, but channel enlargement and other hydrological changes there have reduced the frequency of backwater flooding by 42% since 1880. In addition, operation of the water control structure on the lake has altered its hydrological regime to be more regular among years. Historic stage analysis revealed current lake levels are lower in the high‐water spring, less variable in the dry period, and lack the extreme high‐water events of 100+ years ago, all of which facilitate the expansion of woody vegetation.
For floodplain forests such as bottomland hardwood forests, large fluctuations in moisture availability can lead to stress from both flooded as well as drought conditions. Likewise, these forests can be diverse in species composition and the water use and drought strategies of co-occurring species will impact surrounding hydrology, nutrient dynamics and productivity. Therefore, the objectives of this study were to compare water use, canopy stomatal conductance and its response to environmental drivers in co-occurring bottomland hardwood species from four genera (Carya, Fraxinus, Quercus, Ulmus) during a drought and average rainfall year. Water use was similar across years in cherrybark oak and winged elm. For swamp chestnut oak, willow oak and shagbark hickory water use was about two thirds in the drought year compared with the average rainfall year and in American elm and green ash it was about one half. Species also varied in their responses of water use to VPD, reference canopy stomatal conductance values, and the timing of leaf senescence during the drought and average rainfall year which will impact ecosystem processes based on drought conditions and species composition. Shagbark hickory, winged elm and swamp chestnut oak exhibited the most declines in water use due to soil saturation. In general, species exhibited a tradeoff between flood tolerance and drought tolerance as well as between maximal water use potential and drought tolerance. In total, differences in water use and its response to environmental drivers during drought and non-drought years for bottomland hardwood forests will depend on species composition and these findings can benefit modeling efforts in temperate floodplain forests.
Extreme floods caused by dike or dam breaks have led to substantial damage to various types of vegetation, including forests, orchards, grass, and crops. Many factors affect the impacts of extreme floods on plants, e.g., flood parameters, plant characteristics and natural factors. However, these factors have never been systematically analyzed or considered when evaluating the impacts of extreme floods on plants. Firstly, we summarized the main influencing factors and simplified them into six categories: temperature, geomorphic change, plant age, flood velocity, ratio of the flood depth to the plant height, and ratio of the flood duration to the plant waterlogging tolerance time. Secondly, we proposed the two indices of unit risk biomass (URB) and total risk biomass (TRB) to represent the impacts of floods on plants regionally and over the entire inundated area, respectively. In addition, the calculation methods of URB and TRB considering plant biomass and the comprehensive influence coefficient (I) were put forward. To calculate I, we considered the six influencing factors with different weights according to their importance and varying conditions. The flood parameters and geomorphic changes caused by a simulated dam-break flood of Luhun Reservoir in China were then calculated. Furthermore, we divided a year into six time periods according to the species and growth characteristics of the plants in the inundated area. Then we evaluated the impacts of the dam-break flood on the plants during each period. The results showed that: (a) the URB varied with space in the inundated area; (b) because of the large inundation area of crops, the TRB was far greater than that of forests and orchards and affected the TRB of the whole inundated area; and (c) both the URB and TRB changed with time with the changes in crop species, crop parameters and temperature.
The direct human impact on terrestrial ecosystems is extensive, and only the most inaccessible regions free of human influence. Deforestation, desertification, biodiversity loss, loss of productivity potential, soil erosion, and pollution are ongoing processes associated with landscape degradation. Reversing degradation requires time and consistent effort. The realization that simply preserving extant nondegraded natural ecosystems will be insufficient to address global environmental problems has led to increased reliance on passive and active restoration to counter the effects of landscape degradation. Responding to the adverse consequences of land degradation requires a two-pronged approach: (1) avoiding or at least reducing degradation and (2) restoring degraded ecosystems. Land-degradation neutrality takes the first approach; its objective is to maintain or improve the condition of land resources, including restoration of natural and seminatural ecosystems. Forest landscape restoration takes the second path and underpins the Bonn Challenge that seeks to bring 150 million ha of the world’s deforested and degraded land into restoration by 2020, and 350 million ha by 2030. Soil recovery is basic to both pathways; this includes reducing soil loss and improving soil quality and soil health, especially maintaining and increasing organic matter.
Plant roots assemble two distinct microbial compartments: the rhizosphere (microbes in soil surrounding roots) and the endosphere (microbes within roots). Our knowledge of fungal community assembly in these compartments is limited, especially in wetlands. We tested the hypothesis that biotic factors would have direct effects on rhizosphere and endosphere assembly, while abiotic factors would have direct and indirect effects. Using a field study, we examined the influences of salinity, water level and biotic factors on baldcypress (Taxodium distichum) fungal communities. We found that endosphere fungi were correlated with host density and canopy cover as opposed to rhizosphere, suggesting that hosts can impose selective filters on fungi colonizing into their roots. Meanwhile, local abiotic conditions strongly influenced both rhizosphere and endosphere diversity in opposite patterns: e.g. highest endosphere diversity (hump-shaped) while lowest rhizosphere diversity (U-shaped) at intermediate salinity levels. These results indicate that the assembly and structure for the root endosphere and rhizosphere within a host can be shaped by different processes. Our results also highlight the importance of assessing how environmental changes affect plant and plant-associated fungal communities in wetland ecosystems where saltwater intrusion and sea level rise are major threats to both plant and fungal communities.
Survival of planted trees is commonly used as a performance metric for compensatory mitigation wetlands. However, establishing floodplain forest through planting is difficult due to flood-induced tree mortality. We used multiyear tree census and hydrologic data from 17 compensatory mitigation projects in Illinois, USA, to relate planted and volunteer tree establishment to flood frequency, depth, and duration. Annual survival of planted trees decreased with greater annual maximum flood depth and duration. By the end of official compliance monitoring, sites with greater flood exposure had greater planted tree mortality. We resurveyed 10 sites that were at least 10 years old, and found that long-term tree survival was significantly lower in sites with greater flood exposure. Naturally colonizing trees differed in species composition from planted trees; specifically, wind dispersed species were well-represented among volunteer trees, whereas hard mast species were absent. There was no clear relationship between volunteer tree recruitment and measured flood variables. Across all sites, compliance with tree survival standards was poor, but influenced by hydrologic conditions. Current performance standards for tree survival may be unrealistic in restored wetlands that are exposed to long-duration floods. Regulators and practitioners should seek alternative methods to establish desired floodplain forest structure and function.
This report documents the development of quantitative
measures (indicators) of ecosystem structure and function for
use in a Habitat Needs Assessment (HNA) for the Upper Mississippi
River System (UMRS). HNAs are led periodically by
the U.S. Army Corps of Engineers’ Upper Mississippi River
Restoration (UMRR) Program, which is the primary habitat
restoration program on the UMRS. The UMRR Program helps
determine how Federal, State and nongovernmental agencies
can best address environmental issues on one of the world’s
largest and most diverse river systems. Each indicator in this
report represents at least one management objective developed
for the river system. These objectives were developed in a
previous planning effort using an ecosystem management conceptual
framework (USACE, 2011). The objectives represent
five essential ecosystem characteristics: hydraulics and hydrology,
biogeochemistry, geomorphology, habitat, and biota.
Subsequent to the 2011 planning effort, the UMRR increased
its focus on improving the health and resilience of the UMRS
(Bouska et al. 2018). The indicators presented here are based
on the five essential ecosystem characteristics and four aspects
of ecosystems thought to support general ecosystem resilience
(the ability of an ecosystem to adapt and respond to
disturbances): (1) connectivity, (2) diversity and redundancy,
(3) controlling variables, and (4) slow processes. Thus, we
developed indicators that quantify both essential ecosystem
characteristics and characteristics of a resilient river system.
The indicators documented in this report focus on important
aspects of river floodplain hydrogeomorphology, given the
fundamental role hydrogeomorphology plays in determining
habitat conditions and ecosystem health and resilience at
broad geographic scales. The information contained within
this report provides a broader scale (for example, systemwide)
context for management decisions made at finer scales
(for example, within river reaches or at project sites) and is
designed for use in the formal system-wide Habitat Needs
Assessment II (HNA–II) led by the UMRR Program.
Growth, biomass, and survival of bald cypress (Taxodium distichum [L.] Richard), water tupelo (Nyssa aquatica L.), black willow (Salix nigra Marshall), and button bush (Cephalanthus occidentalis L.) were examined in a 3 times 3 factorial experiment varying water temperatures (AMBIENT, MID, and HIGH [~40 C]) and water levels (DRAINED, SATURATED, and FLOODED). Stem diameter and height, biomass, and survivorship for water tupelo and bald cypress were all reduced by the HIGH/FLOODED treatment. Black willow growth had the greatest variability among nonlethal flooding and temperature treatments, and achieved the greatest biomass of the four species. In the HIGH/FLOODED treatment, however, only 47% of the black willow seedlings survived and stem diameter, height, and biomass of survivors were greatly reduced. Button bush had intermediate variability of growth to the nonlethal treatments as compared to the other study species. Survival of button bush seedlings in the HIGH/FLOODED treatment was high (87%), but root biomass of the survivors was reduced. Interspecific differences in growth, biomass, survivorship, and morphological characteristics existed among these swamp species to experimental conditions. These responses may help explain vegetation patterns in a thermally impacted swamp.
Core Ideas
Previous tree exposure to saturated conditions limited root death after ponding.
Root growth and death had no apparent effect on concentrations of Fe ²⁺ , DOC, or DTP.
Concentrations of Fe ²⁺ were related to water table levels and redox status.
Phosphorus concentrations were controlled by iron reduction and oxidation.
Phosphorus (P) dissolution occurs commonly in wetland soils restored from agricultural land. Associated with P release are high concentrations of dissolved organic carbon (DOC) and Fe ²⁺ . This field study evaluated the effect of a fluctuating water table on the root dynamics of bald cypress ( Taxodium distichum L. Rich.) to determine whether root death created soil reduction microsites, potentially contributing to P dissolution. The study site is a restored Carolina bay wetland with organic soils. Root growth and death were monitored on 16 6‐yr‐old bald cypress using minirhizotrons. Root dynamics, water table levels, and soil porewater chemistry and redox potential in the root zone were monitored for 2 yr. Soil solution samples were analyzed for Fe ²⁺ , pH, DOC, and P. High rates of root growth occurred during dry conditions, whereas root death occurred during sustained periods of saturation, particularly within 20 cm of the surface. Cyclic changes in concentrations of Fe ²⁺ , DOC, and dissolved total P (DTP) were related to water table position but not to changes in root numbers. After sustained periods of saturated conditions, redox potential decreased to 0 mV, Fe ²⁺ increased to 1.75 mg Fe ²⁺ L –1 , and DOC increased to 350 mg L –1 , resulting in peak DTP concentrations of 750 μg L –1 , compared with 100 μg L –1 during dry periods. This study showed that in these high‐C soils (∼20% organic C) rooting dynamics had minimal impact on changes in P concentrations and that P dissolution was largely controlled by Fe reduction processes occurring within the C‐rich soil matrix.
This experiment examined how elevation and control of early successional vegetation would affect the growth and survival of tree species used in restoration. Vegetation was controlled by either mowing or spraying with Accord [glyphosate,-(phosphononomethyl)glycine, in the form of its isopropylamine salt] herbicide. These control methods were applied to either the entire plot or a narrow 1-m strip where seedlings were to be planted. A fifth treatment (control) had seedlings planted into the existing vegetation. Species planted were baldcypress (Taxodium distichum), water tupelo (Nyssa aquatica), willow oak (Quercus phellos), Nuttall oak (Q. nuttallii), overcup oak (Q. lyrata), and cherrybark oak (Q. falcata var. pagodaefolia). Seedlings were randomly planted in late April 1993 with six rows in each plot and six trees per row on a 2×2 m spacing with five replicate plots per treatment. Survival was not enhanced by any competition control treatment, but survival among species differed. All six species had overall survival>90% in autumn 1993. Species survival was affected by several summer floods during 1994. Baldcypress and overcup oak survival was greater than 89%, while water tupelo, Nuttall oak, and willow oak were all approximately 70%, and cherrybark oak was only 29%. By the end of 1995, survival of all species decreased further, but the species groupings remained the same. Survival and height growth of baldcypress and water tupelo were greatest at lower planting elevations. At higher elevations, survival of cherrybark oak and willow oak were greatest, while overcup oak and Nuttall oak were unaffected by elevation. Thus, controlling the herbaceous vegetation did not affect survival or growth as much as relative planting elevation due to site flooding and the flood tolerance of the species. All of the species in this experiment except cherrybark oak were successfully established.
River engineering activities that modify floodplain hydrology induce basic changes in the character of floodplain ecosystems. These may include alteration of processes, natural communities, and land use patterns. This paper focuses on patterns of change that occur within floodplain forests (bottomland hardwoods) of the southern United States. Observations from these complex and productive systems are illustrative of interactions that occur in other flood-plain ecosystems.
Since a definite relationship exists between plant species distribution and timing, frequency and duration of inundation/soil saturation (Bedinger, 1971; Hook and Scholtens, 1978; Whitlow and Harris, 1979; Huffman, 1980; Larson, Bedinger, Bryan, Brown, Huffman, Miller, Rhodes and Touchet, 1981), it should be possible numerically to express the optimum position of various plant species along a wetland hydrologic gradient (Theriot and Sanders, 1986). The resulting numerical values (Flood Tolerance Index) could then be used to estimate the hydrologic regime of areas that have not been substantially altered hydrologically.
Multiple stresses acting simultaneously may affect plants more, the same, or less than each would individually. With the large number of environmental stresses created by man’s activities, determining the effects of a single stress is exceptionally difficult. A single stress (e.g. flooding, high temperature, chemical addition, etc.) usually affects many aspects of the physical environment, producing both positive and negative results. Determining these effects as well as the interactions of several stresses is usually required to achieve a predictive capacity for multiple stresses. Hence, the individual effects of flooding and high substrate temperature will be briefly reviewed, after which their combined effect on the growth, morphology and physiology of woody seedlings will be discussed.
Common woody species growing on tree islands in the Water Conservation Areas of South Florida include redbay, sweetbay, coastal-plain willow, wax myrtle, dahoon holly, cocoplum, pond-apple, red maple, cypress, gumbo-limbo, strangler fig and buttonbush. Very little is known about the flooding tolerance of most of these species. In this paper, we review flooding impact studies, describe the most common species and discuss two methods that might be used to examine woody plant growth response to water level fluctuations. Although tree coring has been used effectively in many areas, the general lack of discernible rings and poor quality rings observed in these species makes this method of questionable use. Dendrometer bands, however, work well in any environment with any species and are recommended for further studies on tree islands.
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