Wetland Tree Research Articles

The influence of land use land cover on the land surface temperature and vegetation index of Pune city, India

Abstract The changes in land use land cover (LULC) over time intensifies the land surface temperature (LST). The variation in LST can be extracted from satellite imagery from different spatial resolutions for the summer month. In this study, through remote sensing and GIS techniques, the LST variation is quantified over different LULC classes from 2000 to 2020 using Landsat data in Pune City. The result shows an overall increase in the percentage of the built from 68.43% in 2000 to 85.31% in 2020, displaying a 16.88% rise during the study period. Further, the normalized difference vegetation index (NDVI) is extracted from the satellite imagery at different spatial resolutions for the summer months, and is quantified over the LULC classes for the duration of the study. The extreme variation in the mean NDVI values is seen in the areas with salt pans, semi arid areas, wetland-sparse vegetation and wetland–tree cover, i.e. areas near water bodies and the peripheral areas with less vegetation. The association of NDVI with LST shows a negative correlation that justifies the rise in surface temperature with the intensity of vegetation in the city. The results of this study shall help the planners, architects and policy makers to evaluate the current status of urbanisation, to make informed choices that lead to sustainable cities.

Leaf Physiological Responses and Early Senescence Are Linked to Reflectance Spectra in Salt-Sensitive Coastal Tree Species

Salt-sensitive trees in coastal wetlands are dying as forests transition to marsh and open water at a rapid pace. Forested wetlands are experiencing repeated saltwater exposure due to the frequency and severity of climatic events, sea-level rise, and human infrastructure expansion. Understanding the diverse responses of trees to saltwater exposure can help identify taxa that may provide early warning signals of salinity stress in forests at broader scales. To isolate the impacts of saltwater exposure on trees, we performed an experiment to investigate the leaf-level physiology of six tree species when exposed to oligohaline and mesohaline treatments. We found that species exposed to 3–6 parts per thousand (ppt) salinity had idiosyncratic responses of plant performance that were species-specific. Saltwater exposure impacted leaf photochemistry and caused early senescence in Acer rubrum, the most salt-sensitive species tested, but did not cause any impacts on plant water use in treatments with <6 ppt. Interestingly, leaf spectral reflectance was correlated with the operating efficiency of photosystem II (PSII) photochemistry in A. rubrum leaves before leaf physiological processes were impacted by salinity treatments. Our results suggest that the timing and frequency of saltwater intrusion events are likely to be more detrimental to wetland tree performance than salinity concentrations.

Measuring Methane Stemming from Tree Stems

Wetland tree stem emissions have emerged as a significant contributor to the global methane budget. A new study tracks how they vary by season, location, and hydrological conditions.

Sciomyzidae (Diptera) Assemblages in Constructed and Natural Wetlands: Implications for Constructed Wetland Design

Wetlands constructed primarily for the treatment of wastewaters have been shown to have a role in enhancing biodiversity. However, while most biodiversity studies of constructed wetlands focus on the larger, more iconic animal groups, there is a paucity of information on the aerial phases of wetland invertebrate species associated with constructed wetlands. This study compares Sciomyzidae (Diptera) assemblages, established indicators of wetland dipteran communities, in Irish constructed and natural wetlands, in addition to determining the impacts of water quality and surrounding habitats on Sciomyzidae community structure. Natural wetlands had significantly greater species richness, abundances and diversity (measured as Shannon’s entropy) of sciomyzid flies than constructed wetlands. Nevertheless, although concentrations of nitrogen and phosphorus in waters were significantly greater in constructed wetlands, seven of the eight constructed wetlands examined hosted species of Sciomyzidae listed as scarce or threatened in Britain. In addition, sciomyzid species richness increased as areas of semi-natural habitat immediately surrounding constructed and natural wetlands increased. Composition of Sciomyzidae assembalges in both natural and constructed wetlands were analysed. The results of this study demonstrate that constructed wetlands can be important contributors to biodiversity particularly in the context of current losses of natural wetlands worldwide. The importance of habitats immediately surrounding constructed wetlands also highlights the need for relatively simple design recommendations (e.g. wet grassland creation or judicious planting of wetland trees) that could enhance the biodiversity of existing and future constructed wetlands.

Diversity of bee tree (sambit) for Apis dorsata conservation in Membalong, Belitung Regency, Indonesia

The land transformation of forests to monoculture threatened the existence of biodiversity in Belitung, including the bee trees (local name: sambit) for Apis dorsata nesting. Bee farmers are having difficulty finding numerous kinds of bee trees. The objectives of this study were (1) to identify the species of bee trees, (2) to characterize the nesting branches of the bee tree, and (3) to identify the ecosystem of the bee trees in three villages in Membalong, Belitung Regency. Data were collected using: (1) interviewing bee farmers, (2) measurements of nesting branches, and (3) exploring the bee tree ecosystems. We discovered 22 species (13 families) of bee trees, with Myrtaceae was the most frequent. Syzygium cymosum (local name: mengkeling) was a common nesting tree of A. dorsata. The characteristics of bee trees were: height of the nesting branch: 7.85 ± 3.80 m above the ground, length of the branch: 2.74 ± 1.43 m, and the incline of the branch: 20.20° ± 2.57°. We found bee trees in terrestrial ecosystems (primary and secondary heath forests) and wetlands (swamps and mangroves). The last ecosystem was a new finding. We suggest local communities cultivate the native plants and reduce the area of forest land used.

Karacabey Kıyı Subasar Ormanlarında Kızılağaç ve Dişbudak yeşil yapraklarının biyokimyasal bileşimi üzerinde tuzlu su girişinin etkisi

Coastal forested wetlands provide substantial benefits to society, such as wave attenuation, erosion control, biodiversity support, and carbon sequestration. Many of these unique coastal ecosystems have been drained for various reasons, while those that remain are now threatened by salt water intrusion and sea level rise due to climate change. In this study, we aimed to investigate the effects of soil salinity on the biochemical components of the fresh leaves of alder (Alnus glutinosa L. Gaertn) and ash tree (Fraxinus angustifolia Vahl.) which are the dominant tree species in Karacabey coastal forested wetland next to the Sea of Marmara in Türkiye. For this purpose, fresh leaf and soil samples of alder and ash trees were collected from three zones (Z1: 0-1 km, Z2: 1 to 2 km and Z3: 2 to 3 km) from the inner border (Z3) of the forested wetland to the coastline (Z1) of the Sea of Marmara. The fresh leaf samples were analyzed for photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), anthocyanin, xanthophylls, free amino acids, total nitrate, proline, total polyphenols, total soluble tannins, total phenolic compounds, glucose, sucrose and total carbohydrates. The soil samples were analyzed for soil pH, electrical conductivity and soil texture. The results showed that the soil salinity decreased from the coastline (Z1) towards the inner border (Z3). Similarly, mean photosynthetic pigments and anthocyanin, xanthophyll also decreased from the Z1 towards Z3, whereas mean total polyphenols and total soluble tannin concentrations increased for the both tree species. The other biochemical compounds showed either an increase or a decrease according to the tree species. These pioneer results illustrate the important point that biotic or abiotic environment in which tree grows significantly change the specific biochemical components in the fresh leaves of alder and ash trees in the coastal forested wetlands. In turn, these changes may result in variation in nutrient cycling, carbon cycling, and organic matter turnover rates in these forest ecosystems.

Geomorphodynamics, evolution, and ecology of vertical roots.

The roots of some coastal and wetland trees grow peculiar vertical protrusions, the function of which remains unclear. Here, using computational simulations based on first-principles fluid and sedimentation dynamics, we argue that the protrusions work together to create an elevated patch of sediment downstream of the tree, thereby creating its own fertile flood-protected breeding grounds for the seedlings. In our simulations, we vary the vertical root diameter, root spacing and total root area and show that there is an optimal vertical root spacing that depends on root thickness. Next, we quantify and discuss the cooperative effects between adjacent vertical root patches. Lastly, by varying vertical root spacing of a patch of trees, we estimate a maximal vegetation density for which vertical-root production has a beneficial geomorphological response. Our hypothesis suggests that vertical roots, such as the 'knee roots' of baldcypress trees, have an important role in shaping riparian geomorphology and community structure.

Response of tree species in cypress (Taxodium spp.) domes of central Florida to a hydrologic gradient

Cypress domes are isolated wetlands dominated by cypress (Taxodium spp.) with multiple subdominant species. Although one of the most common wetlands in the southeastern United States, the number and extent of cypress domes are progressively declining. While tree communities must be resilient to survive both extended periods of flooding and desiccation associated with climate cycles, ongoing changes in land use and climate are altering hydrologic extremes and potentially exceeding the resilience of species. Upland species such as pines and oaks can increase in density in response to persistent shortened hydroperiod, while mature wetland trees including cypress and tupelo can persist for extended periods. This study investigated tree community structure in cypress domes across a gradient of hydroperiods and water depths potentially experienced by cypress domes with altered hydrology. Three decades of water level data were used to describe cypress dome tree community responses to long-term, chronic alterations to hydrology.The tree community structure of cypress dome was correlated with average annual hydroperiod and water depth, but maximum water depth was not significant. Nyssa sylvatica was correlated with extended hydroperiods/deeper water depths, while both Quercus laurifolia and Pinus elliottii correlated with reduced hydrology. The presence of cypress was not correlated with hydrology, presumably because of its dominance in all sample wetlands. Mature (>6 m) wetland trees remained dominant in all sample wetlands with non-wetland trees showing increased abundance when hydroperiods and water depths were below 3 months and 0.075 m, respectively. Sub-adult (<6 m) non-wetland trees became increasingly important when hydroperiods fell below 6 months and were dominant below 3 months. Wetland tree recruitment was reduced when hydroperiods were altered to less than three months and longer than nine months; and average water depths were altered to <0.075 m and>0.225 m. Our study indicates that cypress dome communities may not be as resilient as previously thought. The long-term persistence of cypress domes is not dependent on the ability of mature wetland trees to survive extended periods of flood and drought, but instead maintaining hydrology and recruitment of wetland trees. By utilizing a long-term hydrologic database, a tipping point for cypress domes was observed for water depth and duration of inundation, beyond which the long-term persistence of these systems is in jeopardy.

Geographic Variation in Survival and Growth of Atlantic White-Cedar (Chamaecyparis Thyoides [L.] B.S.P.): Implications for Artificial Regeneration of a Declining Species

Abstract Atlantic white-cedar (Chamaecyparis thyoides [L.] B.S.P.; AWC), a wetland tree species native to the eastern United States, is declining rangewide. This decline has stimulated interest in restoring AWC in parts of its range. However, restoration could benefit from more research on this species, especially that focus on where to source seedlings for artificial reforestation. This study presents results out to years 18–20 from a southern New Jersey common garden established in the early 2000s as part of the first rangewide provenance planting of AWC. The goal of this research was to expand our understanding of intraspecific variation in AWC linked to the geographic origin of genetic sources. Results indicated that genotype performance was linked to their geographic origin and that local sources were among the top performers when taking all metrics into consideration (e.g., survival, height, basal area). Top-performing provenances were sourced within plus or minus two decimal degrees latitude of the planting site. Although local sources remain suitable for artificial regeneration of this species in southern New Jersey, nearby southern sources could be deployed to achieve out-planting success and conservation of this imperiled species in a warming climate. We hope this work will inform AWC restoration efforts and bring visibility to this declining wetland species.

Mercury movement from Hg-enriched wetland soils to arboreal food webs: a weak role for folivory

Mercury (Hg) is a toxicant of concern, particularly in aquatic food webs. Mercury can move to terrestrial systems through consumption of aquatic prey or emergence of insects with aquatic larval phases. The possible movement of Hg from sediments to wetland plants and into terrestrial food webs though primary consumers has received less attention. We investigated differences and correlations in Hg in soil, wood and leaves of willows (Salix caroliniana) and folivorous beetles from a wetland with enhanced levels of Hg. Further, we compared samples from tree islands that had enriched Hg in soil through bird guano with control islands. Hg in any sample type did not correlate with Hg in any other sample type from the same island. We found higher [Hg] in soils and significantly higher [Hg] in leaves from colony islands, while [Hg] in beetles appeared to be higher in control islands. In any case, despite comparatively high [Hg] in soil and leaves, Hg in folivorous beetles was below detection levels and lower than that reported from other studies. We conclude that movement of Hg from wetland trees to terrestrial food webs through wetland vegetation is negligible in this ecosystem.

A high-quality pseudo-phased genome for Melaleuca quinquenervia shows allelic diversity of NLR-type resistance genes.

Melaleuca quinquenervia (broad-leaved paperbark) is a coastal wetland tree species that serves as a foundation species in eastern Australia, Indonesia, Papua New Guinea, and New Caledonia. While extensively cultivated for its ornamental value, it has also become invasive in regions like Florida, USA. Long-lived trees face diverse pest and pathogen pressures, and plant stress responses rely on immune receptors encoded by the nucleotide-binding leucine-rich repeat (NLR) gene family. However, the comprehensive annotation of NLR encoding genes has been challenging due to their clustering arrangement on chromosomes and highly repetitive domain structure; expansion of the NLR gene family is driven largely by tandem duplication. Additionally, the allelic diversity of the NLR gene family remains largely unexplored in outcrossing tree species, as many genomes are presented in their haploid, collapsed state. We assembled a chromosome-level pseudo-phased genome for M. quinquenervia and described the allelic diversity of plant NLRs using the novel FindPlantNLRs pipeline. Analysis reveals variation in the number of NLR genes on each haplotype, distinct clustering patterns, and differences in the types and numbers of novel integrated domains. The high-quality M. quinquenervia genome assembly establishes a new framework for functional and evolutionary studies of this significant tree species. Our findings suggest that maintaining allelic diversity within the NLR gene family is crucial for enabling responses to environmental stress, particularly in long-lived plants.

Biomass Estimation and Carbon Storage of Taxodium Hybrid Zhongshanshan Plantations in the Yangtze River Basin

As a pivotal wetland tree, Taxodium hybrid Zhongshanshan has been widely planted in the region of Yangtze River for multipurpose of ecological restoration, field shelter, landscape aesthetics as well as carbon sequestration. However, the carbon allocation patterns across distinct stages of stand development of T. Zhongshanshan are poorly documented. Using a sample of 30 trees which were destructively harvested, this study compared 3 models for assessing aboveground biomass. Furthermore, a linear seemingly unrelated regression (SUR) approach was introduced to fit the system of the best selected model that ensured the additivity property. On this basis, biomass and carbon storage of T. Zhongshanshan stands in the Yangtze River Basin (YRB) were fairly estimated. Specifically, the study developed height-diameter at breast (H-DBH) function. The results showed that the selected 3-parameter polynomial model performed better, and the SUR approach provided more accurate estimates of leaf and stem fractions. The total tree biomass was 53.43, 84.87, 140.67, 192.71 and 156.65 t ha−1 in the 9-, 11-, 13-, 15-, and 22-year-old T. Zhongshanshan stands, and contributed averagely 94.40% of the ecosystem biomass accumulation. The current T. Zhongshanshan stands in the YRB area can store 124.76 to 217.64 t ha−1 carbon, of which total tree ranges from 25.32 to 90.89 t ha−1, with 55.19% to 77.66% storing in the soil. The T. Zhongshanshan had continuous potential for carbon storage during its growth, particularly in the incipient stages. The findings of this research are firsthand information for forest managers for the sustainable management of T. Zhongshanshan in the YRB and similar subtropical areas.

Introgression between Betula tianshanica and Betula microphylla and its implications for conservation

Societal Impact StatementIn rapidly changing environments species conservation can be hindered by uncertainties in distinguishing closely related species. Cryptic ongoing hybridization can add further uncertainty and could be beneficial or destructive. Here, we show that a declining birch tree species is hybridizing with a more widespread relative in the Junggar basin, NW China, and their hybrids have been previously named as rare sub‐species. Given the declining numbers of this birch tree, we suggest that conservation effort should aim to slow the rate of anthropogenic habitat loss at this hybrid zone and preserve its pure populations away from the hybrid zone.Summary In areas where closely related species meet, the possibility that they may hybridize must be taken into account by conservationists. Hybridization may have positive or negative consequences for the long‐term future of species. If present, its dynamics need to be understood. Betula microphylla is a declining wetland tree species in NW China that forms a continuum of leaf morphology and geographic distribution with its relative Betula tianshanica. We use ecological niche models to predict the distribution of B. microphylla and B. tianshanica. We use restriction site‐associated DNA sequencing and SSRs to resolve their genetic structure and patterns of allele sharing. Ecological niche models predict an expansion of the range of B. tianshanica into that of B. microphylla since the Last Glacial Maximum and the contraction of B. microphylla's range in the future. Genetic data suggest that the two species have hybridized in the Junggar basin and in the Tianshan Mountains where the two species have co‐occurred in the recent past and in the Altay Mountains where there are no records of B. tianshanica occurrence. Rare populations previously identified as sub‐species of B. microphylla were shown to be of hybrid origin. Further research is needed on the costs and benefits of hybridization between B. microphylla and B. tianshanica in the changing environment of NW China. Our current data suggest that conservation effort should aim to slow the rate of anthropogenic habitat loss at the hybrid zone in the Junggar basin and preserve pure populations far away from the hybrid zone in the Altay Mountains.

Trees as net sinks for methane (CH4 ) and nitrous oxide (N2 O) in the lowland tropical rain forest on volcanic Réunion Island.

Summary Trees are known to emit methane (CH4) and nitrous oxide (N2O), with tropical wetland trees being considerable CH4 sources. Little is known about CH4 and especially N2O exchange of trees growing in tropical rain forests under nonflooded conditions.We determined CH4 and N2O exchange of stems of six dominant tree species, cryptogamic stem covers, soils and volcanic surfaces at the start of the rainy season in a 400‐yr‐old tropical lowland rain forest situated on a basaltic lava flow (Réunion Island). We aimed to understand the unknown role in greenhouse gas fluxes of these atypical tropical rain forests on basaltic lava flows.The stems studied were net sinks for atmospheric CH4 and N2O, as were cryptogams, which seemed to be co‐responsible for the stem uptake. In contrast with more commonly studied rain forests, the soil and previously unexplored volcanic surfaces consumed CH4. Their N2O fluxes were negligible.Greenhouse gas uptake potential by trees and cryptogams constitutes a novel and unique finding, thus showing that plants can serve not only as emitters, but also as consumers of CH4 and N2O. The volcanic tropical lowland rain forest appears to be an important CH4 sink, as well as a possible N2O sink.

Longer duration flooding reduces the growth and sexual reproductive efforts of a keystone wetland tree species

Wetland forests are dependent on flooding; however, general relationships between flooding and tree responses have been elusive, partly due to often coarse characterisations of flooding. In a novel approach, we used individual tree-scale water level data to assess the effect of flooding duration on a keystone wetland tree species. We surveyed 140 Eucalyptus camphora (Mountain Swamp Gum) trees across a swamp forest in both 2012 and 2019. We used TUFLOW to model daily water levels for the period from 2009 to 2019 and determined the flooding history for each surveyed tree. We then assessed the effect of flooding duration and tree size on the survival, growth, condition and extent of sexual reproduction of individual trees. Longer flooding durations limited the basal area growth of larger trees and reduced extent of sexual reproduction. Larger trees had greater basal area growth and signs of sexual reproduction overall. There were no clear effects of flooding duration or tree size on survival or condition. We suggest that for flood-tolerant tree species, prolonged (but not chronic) flooding is likely to result in slower-growing smaller trees potentially without impacts on condition or survival, and that slow tree growth and vegetative regeneration are important strategies for persistence in swamps.

A Small Nimble In Situ Fine-Scale Flux Method for Measuring Tree Stem Greenhouse Gas Emissions and Processes (S.N.I.F.F)

Tree stem methane emissions are gaining increasing attention as an overlooked atmospheric source pathway. Existing methods for measuring tree stem greenhouse gas fluxes and isotopes may provide robust integrated emission estimates, but due to their coarse resolution, the capacity to derive insights into fine-scale dynamics of tree stem emissions is limited. We demonstrate and field test an alternative method that is Small, Nimble, In situ and allows for Fine-scale Flux (‘SNIFF’) measurements, on complex and contrasting stem surfaces. It is lightweight and therefore suitable to remote field locations enabling real-time data observations allowing for field-based, data driven sampling regimes. This method facilitated novel results capturing fine-scale vertical and radial methane flux measurements (5 cm increments) and revealed: (1) 86–89% of methane emissions emanated from the lower 30 cm of sampled wetland tree species; (2) clear vertical and horizontal trends in δ13C-CH4 possibly due to fractionation associated with oxidation and/or mass-dependant fractionation during diffusive transport; and (3) the occurrence of substantial radial heterogeneity. We also compared a variety of up-scaling approaches to estimate methane flux per tree, including novel smartphone 3D photogrammetry that resulted in substantially higher stem surface area estimations (> 16 to 36%) than traditional empirical methods. Utilising small chambers with high radial and vertical resolution capabilities may therefore facilitate more robust future assessments into the drivers, pathways, oxidation sinks and magnitude of tree stem greenhouse gas emissions, and compliment previous broad-scale sampling techniques.

Can germination explain the distribution of tree species in a savanna wetland?

AbstractThe relationship between seed germination and ecological niche is determined by matching germination characteristics with environmental features. In this study, we selected tree species occurring in the largest savanna wetland in South America – the Pantanal. Very few species are endemic or exclusively found in savanna wetlands, and the majority of tree species occurring in the Pantanal are also found in the neighbouring Brazilian Cerrado, a drier vegetation type that does not flood. We investigated the relationship between germination characteristics and occurrence of savanna trees in wetlands testing the hypothesis that such seeds are tolerant to flooding. We also addressed the question of whether seed tolerance to flood, assessed by survival analysis, explains tree distribution along a gradient of flooding intensity. In this flooding gradient, widely distributed species are those that occur in areas subjected to low as well as to high flooding intensity whereas restricted distributed species are those that occur only in areas subjected to a low level of flood. Seeds from tree species occurring in areas subjected to different flooding intensities were collected. Seed tolerance and germination during and after both one and two months of simulated flood were evaluated. Our results show that seeds of most of the studied savanna species tolerated submergence, which helps to explain their occurrence and wide distribution in wetlands. Nevertheless, germination behaviour checked by survival functions (i.e. how germination is distributed over time) partially explained tree species distribution along a flooding gradient. We conclude that seed tolerance to flooding is one of the components of the regeneration niche that determines tree occurrence and distribution at the regional scale, from savanna to wetland, but not at a local scale along a flooding gradient.

Longevity, climate sensitivity, and conservation status of wetland trees at Black River, North Carolina

Bald cypress trees over 2,000-years old have been discovered in the forested wetlands along Black River using dendrochronology and radiocarbon dating. The oldest bald cypress yet documented is at least 2,624-years old, making Taxodium distichum the oldest-known wetland tree species, the oldest living trees in eastern North America, and the fifth oldest known non-clonal tree species on earth. The annual ring-width chronology developed from the ancient Black River bald cypress trees is positively correlated with growing season precipitation totals over the southeastern United States and with atmospheric circulation over the Northern Hemisphere, providing the longest exactly-dated climate proxy yet developed in eastern North America. The Nature Conservancy owns 6,400 ha in their Black River Preserve and the North Carolina legislature is considering establishment of a Black River State Park, but ancient forested wetlands are found along most of this 106 km stream and remain threatened by logging, water pollution, and sea level rise.

Succession, regression and loss: does evidence of saltwater exposure explain recent changes in the tree communities of North Carolina's Coastal Plain?

Coastal plant communities globally are highly vulnerable to future sea-level rise and storm damage, but the extent to which these habitats are affected by the various environmental perturbations associated with chronic salinization remains unclear. In this study, we examine the relationship between North Carolina wetland tree community composition and basal area change and indicators of salinization such as soil salt ion content and elevation. We surveyed 34 forest plots in forested, freshwater wetlands across the Albemarle-Pamlico Peninsula. A subset of our study sites had been sampled during the previous decade as part of the Carolina Vegetation Survey, enabling us to investigate the environmental effects on current community structure, and community change over time. Multi-variate (ordination) analysis and linear regression models of tree community composition revealed that elevation and soil salt content were correlated with changes in total site tree basal area. Shifts in tree community composition were, however, only weakly correlated with indicators of salinization, specifically elevation, soil sulphate and sodium, but not chloride. While the majority of plots experienced gains in basal area over the past decade, consistent with secondary succession, sites with high soil salt content or low elevation experienced basal area (biomass) loss during the same period. The key factors associated with chronic saltwater intrusion (soil ion content) likely explain recent changes in tree biomass, and potential shifts in community composition in low-elevation sites along the North Carolina coast. Not only is it probable that other coastal forest ecosystems worldwide will experience similar stressors and shifts in community biomass and structure as sea levels rise, but the ability of these habitats to deliver key ecosystem services like carbon sequestration and flood defence will be compromised as a result.

Development, growth, and biomass simulations of two common wetland tree species in Texas.

Monitoring the health and condition of wetlands using biological assessments can serve as an effective tool for environmental managers to better evaluate and monitor the status and trends of their wetland ecosystems. Woody species can be used as conspicuous biological assessment tools due to their direct response to environmental change, such as hydrologic alteration. The purpose of this study is to use field-measured morphological measurement indices to develop and optimize tree growth parameters and growth curves using multi-model combination approach to improve tree biomass estimations. Field morphological investigations were conducted for two common wetland tree species in Texas. A range of morphological characteristics including leaf area index, height, and biomass was measured for black willow (Salix nigra Marsh) and green ash (Fraxinus pennsylvanica) sampled from 15 sites in a wetland near Cameron, Texas. The measured morphological parameters were used to optimize tree growth and development with the ALMANAC model. The developed tree growth parameters and growth curves were subsequently used in the APEX model to simulate tree biomass at the catchment scale. Both models accurately simulated biomass of trees growing in the wetland. This accurate biomass prediction will be useful to advance science to better monitor and assess wetland health on a large scale (e.g. national or global).