نتایج جستجو برای: leaf canopy
تعداد نتایج: 96802 فیلتر نتایج به سال:
We investigated relationships between tree water status, vegetative growth and leaf gas exchange of peach trees growing on different rootstocks under field conditions. Tree water status was manipulated by partially covering (0, approximately 30 and approximately 60%) the tree canopies on individual days and then evaluating the effects of tree water status on vegetative growth and leaf gas excha...
Plant canopy nitrogen (N) is associated with ecosystem processes such as photosynthetic and aboveground net primary production, particularly in forested ecosystems. Sagebrush N is directly relatable to wildlife nutritional status and contributes to assessments of habitat quality, productivity, plant / soil water dynamics and controls on canopy photosynthesis. Hyperspectral remote sensing studie...
A spatially explicit mechanistic model, MAESTRA, was used to separate key parameters affecting transpiration to provide insights into the most influential parameters for accurate predictions of within-crown and within-canopy transpiration. Once validated among Acer rubrum L. genotypes, model responses to different parameterization scenarios were scaled up to stand transpiration (expressed per u...
Climbing plants are a key component of rainforests, but mechanistic approaches to their distribution and abundance are scarce. In a southern temperate rainforest, we addressed whether the dominance of climbing plants across light environments is associated with the expression of ecophysiological traits. In mature forest and canopy gaps, we measured leaf size, specific leaf area, photosynthetic ...
How plants interact with sunlight is central to the existence of life and provides a window to the functioning of ecosystems. Although the basic properties of leaf spectra have been known for decades, interpreting canopy-level spectra is more challenging because leaf-level effects are complicated by a host of stem- and canopy-level traits. Progress has been made through empirical analyses and m...
We develop a simple, analytical model for canopy resistance to canopy–atmosphere gas exchange that is well suited for incorporation into regional-scale land-surface parameterizations. This model exploits the conservative nature of canopy light-use efficiency (LUE) in carbon assimilation that is observed within broad categories of plant species. The model paradigm assumes that under standard env...
Environmental and leaf trait effects on herbivory are supposed to vary among different feeding guilds. Herbivores also show variability in their preferences for plant ontogenetic stages. Along the vertical forest gradient, environmental conditions change, and trees represent juvenile and adult individuals in the understorey and canopy, respectively. This study was conducted in ten forests sites...
Patterns of increasing leaf mass per area (LMA), area-based leaf nitrogen (Narea), and carbon isotope composition ( 13C) with increasing height in the canopy have been attributed to light gradients or hydraulic limitation in tall trees. Theoretical optimal distributions of LMA and Narea that scale with light maximize canopy photosynthesis; however, sub-optimal distributions are often observed d...
Microclimate in different positions on a host plant has strong direct effects on herbivores. But little is known about indirect effects due to changes of leaf traits. We hypothesized that herbivory increases from upper canopy to lower canopy and understory due to a combination of direct and indirect pathways. Furthermore, we hypothesized that herbivory in the understory differs between tree spe...
In this paper, a new method for estimation of vertical leaf area density (LAD) profile of tree canopy using portable scanning lidar is proposed. In this method, which we refer to as the voxel-based canopy profiling (VCP) method, several measurement points surrounding the canopy and optimally inclined laser beams are adopted to facilitate full laser beam illumination of whole canopy up to the in...
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