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Abies Amabilis

The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Douglas G. Sprugel – 1st expert on this subject based on the ideXlab platform

  • Spatial aspects of tree mortality strongly differ between young and old‐growth forests
    Ecology, 2015
    Co-Authors: Andrew J Larson, Douglas G. Sprugel, Janneke Hillerislambers, James A. Lutz, Daniel C. Donato, James A. Freund, Mark E. Swanson, Jerry F Franklin

    Abstract:

    Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, mortality should be primarily density dependent due to competition for light, leading to an increasingly spatially uniform pattern of surviving trees. In contrast, mortality in old-growth forests should be primarily caused by contagious and spatially autocorrelated agents (e.g., insects, wind), causing spatial aggregation of surviving trees to increase through time. We tested these predictions by contrasting a three-decade record of tree mortality from replicated mapped permanent plots located in young ( 300-year-old) Abies Amabilis forests. Trees in young forests died at a rate of 4.42% per year, whereas trees in old-growth forests died at 0.60% per year. Tree mortality in young forests was significantly aggregated, strongly density dependent, and caused live tree patterns to become more uniform through time. Mortality in old-growth forests was spatial…

  • morphological acclimation to understory environments in Abies Amabilis a shade and snow tolerant conifer species of the cascade mountains washington usa
    Tree Physiology, 2008
    Co-Authors: Akira Mori, Eri Mizumachi, Douglas G. Sprugel

    Abstract:

    : Light-related plasticity in a variety of crown morphology and within-tree characteristics was examined in sun and shade saplings of Abies Amabilis Dougl. ex J. Forbes growing in two late-successional forests with different snow regimes in the Cascade Mountains of Washington, USA. Compared with sun saplings, shade saplings typically had broad flat crowns as a result of acclimation at several scales (needle, shoot, branch, crown and whole sapling). Shoots of shade saplings had a smaller needle mass per unit of stem length than shoots of sun saplings, a feature that enhances light-interception efficiency by reducing among-needle shading. The low annual rate of needle production by shade saplings was associated with a longer needle lifespan and slower needle turnover. Reduced needle production within a shoot was reflected at the branch level, with lateral branches of shade saplings having a smaller needle mass than branches of the same length of sun saplings. Reduced allocation to needles permits greater investment in branches and stems, which is necessary to support the horizontally expanding branch system characteristic of shade saplings. Mean branch age of shade saplings was significantly higher than that of sun saplings. Shade saplings had lower needle mass per unit of trunk biomass or total biomass, reflecting greater investment in the trunk as a support organ. Increased investment in support organs in shade was more evident in the snowier habitat. The observed morphological acclimation makes A. Amabilis highly shade and snow-tolerant and thus able to dominate in many late-successional forests in snowy coastal mountain regions.

  • control of transpiration in a 220 year old Abies Amabilis forest
    Forest Ecology and Management, 2001
    Co-Authors: T A Martin, Douglas G. Sprugel, Frederick C Meinzer, Kim J Brown, Jiři Kucera, Thomas M Hinckley

    Abstract:

    Abstract We measured sap flow at the branch and tree levels, and calculated tree transpiration at the stand level, in a 220-year-old Abies Amabilis (Dougl.) Forbes forest. Temporal and spatial patterns of branch sap flow rate per unit leaf area reflected differences in canopy position and diurnal variation in radiation exposure. Average leaf area normalized branch conductance of upper canopy branches ranged from 0.50 to 1.01 mm s−1. Maximum leaf area normalized tree sap flow rates were similar to those previously measured in a younger A. Amabilis forest (about 80 g m−2 leaf area h−1), but dominant trees in the old growth stand transpired approximately three times more per day (up to 281 kg H2O per day) than dominant trees in the younger forest. This difference was attributed primarily to leaf area: dominant trees in the old growth stand had approximately three times more leaf area than those in the younger Abies stand. Crown conductance on a ground area basis varied by an order of magnitude between the smallest and largest trees measured (maximum 4.84 mm s−1 and mean 1.44 mm s−1 versus maximum 37.54 mm s−1 and average 12.16 mm s−1, respectively). There was considerable spatial and temporal variation in stomatal versus boundary layer control of transpiration as expressed by the Ω decoupling coefficient. Ω for the largest measured tree ranged from less than 0.1 to greater than 0.6, and remained above 0.3 for more than 9% of the daylight hours monitored. The degree of decoupling decreased with tree size, with Ω of the smallest tree sampled never exceeding 0.3. Daily stand transpiration ranged from less than 0.4 mm to greater than 3.3 mm depending on radiation and vapor pressure deficit.

Thomas M Hinckley – 2nd expert on this subject based on the ideXlab platform

  • control of transpiration in a 220 year old Abies Amabilis forest
    Forest Ecology and Management, 2001
    Co-Authors: T A Martin, Douglas G. Sprugel, Frederick C Meinzer, Kim J Brown, Jiři Kucera, Thomas M Hinckley

    Abstract:

    Abstract We measured sap flow at the branch and tree levels, and calculated tree transpiration at the stand level, in a 220-year-old Abies Amabilis (Dougl.) Forbes forest. Temporal and spatial patterns of branch sap flow rate per unit leaf area reflected differences in canopy position and diurnal variation in radiation exposure. Average leaf area normalized branch conductance of upper canopy branches ranged from 0.50 to 1.01 mm s−1. Maximum leaf area normalized tree sap flow rates were similar to those previously measured in a younger A. Amabilis forest (about 80 g m−2 leaf area h−1), but dominant trees in the old growth stand transpired approximately three times more per day (up to 281 kg H2O per day) than dominant trees in the younger forest. This difference was attributed primarily to leaf area: dominant trees in the old growth stand had approximately three times more leaf area than those in the younger Abies stand. Crown conductance on a ground area basis varied by an order of magnitude between the smallest and largest trees measured (maximum 4.84 mm s−1 and mean 1.44 mm s−1 versus maximum 37.54 mm s−1 and average 12.16 mm s−1, respectively). There was considerable spatial and temporal variation in stomatal versus boundary layer control of transpiration as expressed by the Ω decoupling coefficient. Ω for the largest measured tree ranged from less than 0.1 to greater than 0.6, and remained above 0.3 for more than 9% of the daylight hours monitored. The degree of decoupling decreased with tree size, with Ω of the smallest tree sampled never exceeding 0.3. Daily stand transpiration ranged from less than 0.4 mm to greater than 3.3 mm depending on radiation and vapor pressure deficit.

  • boundary layer conductance leaf temperature and transpiration of Abies Amabilis branches
    Tree Physiology, 1999
    Co-Authors: Timothy A. Martin, Thomas M Hinckley, Frederick C Meinzer, Douglas G. Sprugel

    Abstract:

    : We used three methods to measure boundary layer conductance to heat transfer (g(bH)) and water vapor transfer (g(bV)) in foliated branches of Abies Amabilis Dougl. ex J. Forbes, a subalpine forest tree that produces clumped shoot morphology on sun-formed branches. Boundary layer conductances estimated in the field from energy balance measurements increased linearly from approximately 10 mm s(-1) at low wind speeds (< 0.1 m s(-1)) to over 150 mm s(-1) at wind speeds of 2.0 m s(-1). Boundary layer conductances measured on shoot models in a wind tunnel were consistently higher than field measurements. The difference between wind tunnel values and field measurements was attributable to variation in path length between the two experimental environments. Boundary layer conductance estimated by subtracting stomatal resistance (r(sV)) measured with a porometer from the total branch vapor phase resistance were unusually small. Sensitivity analysis demonstrated that this method is not suitable for coniferous foliage or when stomatal conductance (g(sV)) is small compared with g(bV). Analysis of the relative magnitudes of g(sV) and g(bV) revealed that, under most conditions, A. Amabilis branches are well coupled (i.e., g(sV) is the dominant controller of transpiration). The boundary layer conductance to heat transfer is small enough that leaf temperature can become substantially higher than air temperature when radiation is high and wind speed is low. Over a two-month period, the maximum difference between leaf and air temperatures exceeded 6 degrees C. Leaf temperature exceeded air temperature by more than 2 degrees C on 10% of the daylight hours during this period. Consideration of both the photosynthetic temperature response of A. Amabilis foliage as well as the summer air temperature conditions in its habitat suggests that these elevated leaf temperatures do not have a significant impact on carbon gain during the growing season.

  • Boundary layer conductance, leaf temperature and transpiration of Abies Amabilis branches
    Tree Physiology, 1999
    Co-Authors: Timothy A. Martin, Thomas M Hinckley, Frederick C Meinzer, Douglas G. Sprugel

    Abstract:

    We used three methods to measure boundary layer conductance to heat transfer (gbH) and water vapor transfer (gbV) in foliated branches of Abies Amabilis Dougl. ex J. Forbes, a subalpine forest tree that produces clumped shoot morphology on sun-formed branches. Boundary layer conductances estimated in the field from energy balance measurements increased linearly from approximately 10 mm s竏・ at low wind speeds (< 0.1 m s竏・) to over 150 mm s竏・ at wind speeds of 2.0 m s竏・. Boundary layer conductances measured on shoot models in a wind tunnel were consistently higher than field measurements. The difference between wind tunnel values and field measurements was attributable to variation in path length between the two experimental environments. Boundary layer conductance estimated by subtracting stomatal resistance (rsV) measured with a porometer from the total branch vapor phase resistance were unusually small. Sensitivity analysis demonstrated that this method is not suitable for coniferous foliage or when stomatal conductance (gsV) is small compared with gbV. Analysis of the relative magnitudes of gsV and gbV revealed that, under most conditions, A. Amabilis branches are well coupled (i.e., gsV is the dominant controller of transpiration). The boundary layer conductance to heat transfer is small enough that leaf temperature can become substantially higher than air temperature when radiation is high and wind speed is low. Over a two-month period, the maximum difference between leaf and air temperatures exceeded 6 ツーC. Leaf temperature exceeded air temperature by more than 2 ツーC on 10% of the daylight hours during this period. Consideration of both the photosynthetic temperature response of A. Amabilis foliage as well as the summer air temperature conditions in its habitat suggests that these elevated leaf temperatures do not have a significant impact on carbon gain during the growing season.

Akira Mori – 3rd expert on this subject based on the ideXlab platform

  • convergence of leaf display and photosynthetic characteristics of understory Abies Amabilis and tsuga heterophylla in an old growth forest in southwestern washington state usa
    Tree Physiology, 2009
    Co-Authors: Hiroaki Ishii, Kenichi Yoshimura, Akira Mori

    Abstract:

    Summary We compared the morphological and physiological characteristics of understory trees of Abies Amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes and Tsuga heterophylla (Raf.) Sarg. growing adjacent to each other in an old-growth forest in southwestern Washington State, USA. We hypothesized that, despite contrasting branching patterns and crown architectures, the two species should exhibit convergence in leaf display and photosynthetic gain per light intercepting area, because these are important properties determining their survival in the light-limited understory. The branching pattern of A. Amabilis was regular (normal shoot-length distribution, less variable branching angle and bifurcation ratio), whereas that of T. heterophylla was more plastic (positively skewed shoot-length distribution, more variable branching angle and bifurcation ratio). The two species had similar shoot morphologies: number of leaves per unit shoot length and leaf to axis dry mass ratio. Leaf morphology, in contrast, was significantly different. Leaves of A. Amabilis were larger and heavier than those of T. heterophylla, which resulted in lower mass-based photosynthetic rate for A. Amabilis. Despite these differences, the two species had similar levels of leaf overlap and area-based photosynthetic characteristics. Needle longevity of A. Amabilis was nearly twice that of T. heterophylla. The leaf N contents of current and 1-year-old leaves were lower for A. Amabilis than for T. heterophylla. However, the leaf N content of A. Amabilis did not change from current leaves to 6-year-old leaves, whereas that of T. heterophylla decreased with increasing leaf age. Abies Amabilis had deeper crowns than T. heterophylla and retained branches with low relative growth rates. Longer branch retention may compensate for the lower branch-level assimilation rate of A. Amabilis. We inferred that the convergence of leaf display and photosynthetic characteristics between A. Amabilis and T. heterophylla may contribute to the persistence of both species in the understory of this forest.

  • morphological acclimation to understory environments in Abies Amabilis a shade and snow tolerant conifer species of the cascade mountains washington usa
    Tree Physiology, 2008
    Co-Authors: Akira Mori, Eri Mizumachi, Douglas G. Sprugel

    Abstract:

    : Light-related plasticity in a variety of crown morphology and within-tree characteristics was examined in sun and shade saplings of Abies Amabilis Dougl. ex J. Forbes growing in two late-successional forests with different snow regimes in the Cascade Mountains of Washington, USA. Compared with sun saplings, shade saplings typically had broad flat crowns as a result of acclimation at several scales (needle, shoot, branch, crown and whole sapling). Shoots of shade saplings had a smaller needle mass per unit of stem length than shoots of sun saplings, a feature that enhances light-interception efficiency by reducing among-needle shading. The low annual rate of needle production by shade saplings was associated with a longer needle lifespan and slower needle turnover. Reduced needle production within a shoot was reflected at the branch level, with lateral branches of shade saplings having a smaller needle mass than branches of the same length of sun saplings. Reduced allocation to needles permits greater investment in branches and stems, which is necessary to support the horizontally expanding branch system characteristic of shade saplings. Mean branch age of shade saplings was significantly higher than that of sun saplings. Shade saplings had lower needle mass per unit of trunk biomass or total biomass, reflecting greater investment in the trunk as a support organ. Increased investment in support organs in shade was more evident in the snowier habitat. The observed morphological acclimation makes A. Amabilis highly shade and snow-tolerant and thus able to dominate in many late-successional forests in snowy coastal mountain regions.