Browsing by Subject "temperate forest"

Now showing 1 - 3 of 3
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    Generality of leaf traits relationships: a test across six biomes
    (Ecological Society of America, 1999) Reich, Peter B; Ellsworth, David S; Walters, Michael B; Vose, James M; Gresham, Charles; Volin, John C; Bowman, William D
    Convergence in interspecific leaf trait relationships across diverse taxonomic groups and biomes would have important evolutionary and ecological implications. Such convergence has been hypothesized to result from trade-offs that limit the combination of plant traits for any species. Here we address this issue by testing for biome differences in the slope and intercept of interspecific relationships among leaf traits: longevity, net photosynthetic capacity (Amax), leaf diffusive conductance (Gs), specific leaf area (SLA), and nitrogen (N) status, for more than 100 species in six distinct biomes of the Americas. The six biomes were: alpine tundra–subalpine forest ecotone, cold temperate forest–prairie ecotone, montane cool temperate forest, desert shrubland, subtropical forest, and tropical rain forest. Despite large differences in climate and evolutionary history, in all biomes mass-based leaf N (Nmass), SLA, Gs, and Amax were positively related to one another and decreased with increasing leaf life span. The relationships between pairs of leaf traits exhibited similar slopes among biomes, suggesting a predictable set of scaling relationships among key leaf morphological, chemical, and metabolic traits that are replicated globally among terrestrial ecosystems regardless of biome or vegetation type. However, the intercept (i.e., the overall elevation of regression lines) of relationships between pairs of leaf traits usually differed among biomes. With increasing aridity across sites, species had greater Amax for a given level of Gs and lower SLA for any given leaf life span. Using principal components analysis, most variation among species was explained by an axis related to mass-based leaf traits (Amax, N, and SLA) while a second axis reflected climate, Gs, and other area-based leaf traits.
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    Nitrogen mineralization and productivity in 50 hardwood and conifer stands on diverse soils
    (Ecological Society of America, 1997) Reich, Peter B; Grigal, David F; Aber, John D; Gower, Stith T
    The generality of relationships between soil net nitrogen (N) mineralization, aboveground N cycling, and aboveground net primary production (ANPP) for temperate forest ecosystems is unclear. It is also not known whether these variables and their relationships differ between evergreen and deciduous forests, or across soil types. To address these questions we compiled data on annual rates of in situ net N mineralization and ANPP for 16 conifer and 34 hardwood forests, including plantations and natural stands on a range of soils at six locations in Wisconsin and Minnesota, USA. For 31 natural stands, 48 stands with native species (including plantations), and all data, ANPP increased linearly with annual net N mineralization rates. Native evergreen conifer and two deciduous hardwood types (oaks and mesic hardwoods) followed similar patterns in this regression, indicating common functional relationships at the ecosystem level. The relationship of N mineralization and ANPP differed between finer textured Alfisol soils and sandier Entisols, with higher ANPP at any given N mineralization level in Alfisols. A multiple regression of N mineralization on soil texture (percentage silt plus clay), litterfall N, and mean annual temperature explained 81% of the variance in annual N mineralization for natural stands, and a multiple regression of ANPP on soil texture and annual N mineralization rate explained 83% of the variance in ANPP. Naturally regenerated forest types differed in mean annual net N mineralization, litterfall N, and ANPP, and all were greater in oaks than in mesic hardwoods or conifers, respectively. However, differences among the 50 stands and six locations were largely a result of differences in soils and stand origin. For all natural hardwood stands, ANPP and N mineralization were greater on fine-textured Alfisols than on sandy Entisols. For evergreen conifers, ANPP and N mineralization were greater in plantations on Alfisols than in natural stands on Histosols, Entisols, or Spodosols. Hardwood and evergreen conifer stands did not differ significantly in ANPP or N mineralization on comparable soils and stand origin: they differed neither as plantations on Alfisols nor as natural stands on Entisols. This suggests that observed average differences among natural forest types in ANPP and N mineralization resulted largely from variation in their distribution on differing soils, and not from feedback effects on N mineralization or differing productivity per available N. These data suggest that, at a regional scale, at least half of the variation in ANPP can be attributed to variation in annual N mineralization. Both ANPP and N mineralization differ more strongly with soil type/parent material than with forest type; ANPP at any given level of N mineralization is higher on silty/loamy Alfisols than on sandy Entisols, Histosols, or Spodosols, but not different for coniferous and broad-leaved deciduous species. There is no indication of N saturation of ANPP within the range of natural N availability in these forests.
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    Phenological data (2009-2013) for ten tree species grown under experimental warming in northern Minnesota, USA
    (2020-03-27) Montgomery, Rebecca A; Stefanski, Artur; Reich, Peter B; Rice, Karen E; rebeccam@umn.edu; Montgomery, Rebecca A; University of Minnesota Forest Ecology Group
    This dataset contains five years of data on time of budburst, growing degree days at the time of budburst, time of senescence and phenological growing season length phenology data for ten tree species native to Minnesota, USA. Data were collected in a long-term open-air warming experiment located a the Cloquet Forestry Center, Cloquet, MN, USA and the Hubachek Wilderness Research Center, Ely, MN, USA. The design was a 2 (site) X 2 (habitat) x 3 (warming treatment) factorial, with 6 replicates (2 per block) for a total of 72 7.1 m2 circular plots. Species include: Quercus rubra, Quercus macrocarpa, Pinus banksiana, Pinus strobus, Populus tremuloides, Betula papyrifera, Abies balsamea, Picea glauca, Acer rubrum, Acer saccharum. These data are released in conjunction with a publication.