Bottomland hardwood productivity: case study in a rapidly subsiding, Louisiana, USA, watershed (original) (raw)
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Quantifying flooding effects on hardwood seedling survival and growth for bottomland restoration
New Forests, 2012
Growing interest worldwide in bottomland hardwood restoration necessitates improved ecological understanding of flooding effects on forest tree seedlings using methodology that accurately reflects field conditions. We examined hardwood seedling survival and growth in an outdoor laboratory where the timing, depth, duration, and flow rate of flood water can be carefully controlled while simulating natural soil conditions occurring in floodplains. Flooding treatments were initiated in mid-May and included partial inundation (15-20 cm) during the growing season for 5-week flowing, 5-week standing, 3-week flowing, and control. We monitored the vigor, survival, and growth (changes in basal diameter and stem length) of six hardwood species representing a wide range in expected flood tolerance including eastern cottonwood (Populus deltoides Bartr. Ex Marsh.), pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd.), bur oak (Q. macrocarpa Michx.), black walnut (Juglans nigra L.), and pecan [Carya illinoensis (Wangenh.) K. Koch]. All stock was 1-0 bareroot except that cuttings were used for eastern cottonwood. Five species-eastern cottonwood, bur oak, swamp white oak, pin oak, and pecan-exhibited high survival probabilities ([0.62 for cottonwood; [0.77 for the others) regardless of flood treatment. But of the survivors, only eastern cottonwood and swamp white oak maintained positive growth and healthy green foliage. Despite high survival, bur oak and pin oak suffered stem growth losses and exhibited chlorotic foliage in flood treatments suggesting greater vulnerability to other abiotic or biotic stresses if outplanted on flood-prone sites. Pecan also suffered stem dieback in controls suggesting vulnerability to competition and browsing when outplanted despite high survival after flooding. Our quantitative data helps to confirm and/or refine previously published qualitative flood tolerance ratings for these species, and describes operation of an in situ outdoor flood experiment laboratory that may prove effective in guiding future flood tolerance research.
Effects of flooding regimes on two impounded bottomland hardwood stands
Wetlands, 1995
The relationships between flooding regimes, stand structure, regeneration, and tree stress and mortality were evaluated within two overcup oak (Quercus lyrata)willow oak (Quercus phellos) greentree reservoirs, one impoundment with levees and one without levees. Record rainfall resulted in extensive growing-season flooding in both impoundments; however, the levee system and the topographic relief of the impoundment with levees impeded drainage of surface water and prolonged growing-season flooding. Limited regeneration of all species except overcap oak was observed in both impoundments. In the impoundment with levees, the total number of overcup oak seedlings at peak establishment and overcup oak seedling mortality were related to flooding regimes. In the impoundment without levees, establishment densities were not related to any of the measured environmental variables. Stress and mortality were significantly higher in trees in larger diameter classes, and stress generally increased with flooding. These results suggest that the decision to create GTRs within a stand of naturally flooded bottomland hardwoods should be thoroughly and cautiously reviewed.
Litterfall in the hardwood forest of a minor alluvial-floodplain
Forest Ecology and Management, 2006
Within mature deciduous forests, annual development of foliar biomass is a major component of aboveground net primary production and nutrient demand. As litterfall, this same foliage becomes a dominant annual transfer of biomass and nutrients to the detritus pathway. We report litterfall transfers of a mature bottomland hardwood forest in a minor alluvial-floodplain within the middle Coastal Plain physiographic province
Tree Basal Growth Response to Flooding in a Bottomland Hardwood Forest in Central Ohio 1
JAWRA Journal of the American Water Resources Association, 2008
Tree basal growth in response to flooding regime was evaluated at a 5.2-ha bottomland forest along the Olentangy River in central Ohio. Tree-ring analysis was used to develop a 14-year basal area increment (BAI) (cm 2 ⁄ year) series for 42 canopy trees (representing 10 species) throughout the bottomland. Mean annual BAI was evaluated relative to the frequency and duration of bankfull (>70 m 3 ⁄ s) and high-flood (>154 m 3 ⁄ s) river discharge for a given water year (October 1-September 30) and growing season (April 1-September 30). A significant polynomial relationship was detected between the number of days of high-flood river discharge over a combined two-year period (Year i + Year i ) 1) and mean annual BAI. No significant relationships were detected when only the concurrent-year or previous-year flood regimes were considered or when growing season was considered. A similar relationship was detected when duration of high-flood discharge days and BAI were both evaluated in two-year increments (Year i + Year i ) 1). Mean annual BAI was most influenced by boxelder (Acer negundo) which was the dominant species and exhibited strong agreement with the overall BAI series. In each case, the resulting parabolic curve of tree basal growth in response to flooding suggests an optimal number of flooding days, a response to perturbation consistent with the subsidy-stress model. Dendrochronology may be a useful tool for managers looking to restore environmental flows to regulated rivers.
Bottomland hardwood forest species responses to flooding regimes along an urbanization gradient
Ecological Engineering, 2007
Cephalanthus occidentalis Fraxinus pennsylvanica Quercus shumardii a b s t r a c t Urbanization alters stream hydrology, hence flooding frequency and duration in floodplain wetlands. Potential impacts include shifts in species composition and survival, making restoration and selection of wetland species difficult. Cephalanthus occidentalis, Fraxinus pennsylvanica, and Quercus shumardii seedlings were subjected to experimental flooding regimes typical of floodplain forests in rural and urban settings. Treatments included a rural flood regime with three 7-day floods, an Urban-short flood regime with six 4-day floods, and an Urban-long flood regime with six 10-day floods over a growing season. Specific responses, measured by stem length, leaf area, and leaf, stem, and root biomass, varied between species from different wetland indicator classes. C. occidentalis, a wetland obligate, was well adapted to both urban flooding regimes, whereas productivity of F. pennsylvanica, a facultative wetland species, and Q. shumardii, a facultative species, was significantly reduced by the Urban-long treatment. Growth rates also varied over time, indicating the importance of temporal flooding patterns on species productivity. Because urban flooding regimes directly and selectively alter species productivity, proper restoration methods in urbanizing environments should include species selection based on current and potential future hydrologic conditions and use of reference standards from reference sites subjected to similar urban hydrologic regimes. (M.E. Simmons).
At the Olentangy Wetland Research Park in Columbus, Ohio a hardwood riparian forest (bottomland) was hydrologically restored in June 2000. At the north end of the bottomland, a series of holes were notched in a 2-m tall dike that had separated a 250-m section of the bottomland from the adjacent Olentangy River. This restoration has allowed regular surface flow to occur in this section of the bottomland for the first time in about 100 years. In the southern portion of the bottomland, no impediment has occurred between the river and the bottomland and only one notch was cut in the southern section of the forest to further increase river inflows. This scenario provides an opportunity to examine the initial effect of hydrological restoration on the productivity of a bottomland forest. Net aboveground primary productivity (NAPP) of the northern and southern sections of this bottomland are being compared to determine if productivity has been improved in the bottomland. Initial results from litter traps installed throughout the two sections indicate that leaf, reproductive parts (flowers, seeds, etc.) and woody material (small twigs, bark, etc.) flux were comparable between the two sections. For the months of June through October, mean total litterfall was 450 ± 6 g-dry wt m-2 for the north restored section and 467 ± 30 g m-2 for the south reference section.
EVALUATING THE FLOOD TOLERANCE OF BOTTOMLAND HARDWOOD ARTIFICIAL REPRODUCTION
We experimentally compared the survival and growth after flooding of six bottomland species: eastern cottonwood (cuttings) (Populus deltoides artr. Ex Marsh.), pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd.), bur oak (Q. macrocarpa Michx.), black walnut (Juglans nigra L.), and pecan [Carya illinoensis (Wangenh.) K. Koch]. Flood treatments (5-week flowing, 5-week stagnant, 3-week flowing, and control) were initiated in May, 2004, and plants were evaluated in September. Cottonwood maintained high survival and growth but had a significant basal diameter growth reduction with increased flood duration. Swamp white oak and pin oak each had greater survival than cottonwood, exceeding 95 percent regardless of treatment. Swamp white oak maintained high growth, regardless of treatment. lthough not significant, pin oak and pecan had high survival but reduced growth and bur oak and black walnut had both reduced survival and growth with increased flood duration.
Influence of flood connectivity on bottomland hardwood forest productivity in central Ohio
A. Aboveground net primary productivity (ANPP) in response to ooding and other environmental variables was evaluated at a 5.2-ha bottomland hardwood forest along the Olentangy River in central Ohio, USA. e forest is composed of two distinct sections that were hydrologically enhanced in 2001. To approximate natural ooding, the north section was enhanced by cutting three breaches in a more than 70-year-old arti cial levee. A fourth breach was cut from a natural riverbank in the south section to connect a lateral swale and augment the existing ood regime. e objective of this study was to evaluate various factors that might a ect forest productivity a er restoration. In 2004, ANPP for the forest was estimated at 847 ±50 g m-2 yr-1 (807 ± 86 g m-2 yr-1 in the north section and 869 ±86 g m-2 yr-1 in the south section). Mean ANPP for the entire forest was similar to an estimate prior to restoration and still below productivity levels reported at other bottomland forests along the Olentnagy River and throughout the Midwest U.S. As part of this study, the in uence of ood connectivity and other variables on intra-forest ANPP were also examined. Using daily river-stage data and by monitoring study plots at various ood stages, we estimated the number of days each plot was connected to the river. A signi cant and positive relationship was detected between plot ANPP and the number of days connected to the river during the 2004 water year (Oct. 2003-Sept. 2004). Forest ANPP was also signi cantly related to total tree basal area and topographic variability.
Leaf Litter Decomposition and Nutrient Dynamics in Four Southern Forested Floodplain Communities
Soil Science Society of America Journal, 2001
Decomposition of site-specific litter mixtures was monitored for 100 wk in four Roodplaht communities: (i) a mixed oak community along the Cache River in central Arkansas, (ii) s sweetgum (Liquidambar styracijlua L.)-cherrybark oak (Quercwfalcata vwpagodaefolia ELI.) community along Iatt Creek in central Louisiana, (iii) a sweetgum-swamp tupelo [Nyssu sylvaticu var. bifroru (Walt.) Sarg.] community, and (iv) a laurel oak (Quercus luurifolia Michx.) commnnity along the Coosawhatchie River in southeastern South Carolina. Soil temperature, hydroperiod, and litter quality (C:N, C:P, N:P, fignin:N) were used to interpret differences in the rates of mass loss and nutrient dynamics. After 100 wk, litter mixtures retained 33, 18, 8, and 5% of original mass on the Cache, Coosawhatchie (laurel oak community), Coosawhatchie (sweetgum-swamp tupelo community),
River Research and Applications, 2009
Flood regime and vegetation flood tolerance interact to influence tree growth in riverine landscapes. We studied tree growth in floodplain and upland forests of the Wisconsin River. About a century ago, levees set back from the river were constructed on this floodplain. The levee restricts some floodplain area from overbank flood events, but leaves a portion of active floodplain still inundated by floods. We addressed two questions: (1) how do growth rates of flood-tolerant and flood-intolerant tree species in the floodplain differ with flood regime? (2) At the stand level, how does growth rate differ with flood regime and between floodplain and upland areas? Annual tree growth rates from 1991 to 2000 were determined from tree increment cores for both individual species and stands. Tree growth rates of individual species varied between flood regimes. The most flood-tolerant species (Betula nigra and Fraxinus pennsylvanica) grew faster in areas with active flooding, while the growth of less flood-tolerant species (Quercus velutina and Q. ellipsoidalis) was depressed in swales and active floodplain. However, stand-level tree growth did not differ between the floodplain and upland, or between flood regimes within the floodplain. Therefore, variation in the growth of individual species may not scale up to create differences in stand-level tree growth because forest community composition varies spatially with flood regime. We suggest that growth rates are similar among sites because each community comprises of species adapted to their current flood regime.