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The Influence of Ecosystem and Phylogeny on Tropical Tree Crown Size and Shape
- Source :
- Frontiers in Forests and Global Change, Vol 3 (2020)
- Publication Year :
- 2020
- Publisher :
- Frontiers Media S.A., 2020.
-
Abstract
- The sizes and shapes of tree crowns are of fundamental importance in ecology, yet understanding the forces that determine them remains elusive. A cardinal question facing ecologists is the degree to which general and non-specific versus ecological and context-dependent processes are responsible for shaping tree crowns. Here, we test this question for the first time across diverse tropical ecosystems. Using trees from 20 plots varying in elevation, precipitation, and ecosystem type (savanna-forest transitions) across the paleo- and neo-tropics, we test the relationship between crown dimensions and tree size. By analyzing these scaling relationships across environmental gradients, biogeographic regions, and phylogenetic distance, we extend Metabolic Scaling Theory (MST) predictions to include how local selective pressures shape variation in crown dimensions. Across all sites, we find strong agreement between mean trends and MST predictions for the scaling of crown size and shape, but large variation around the mean. While MST explained approximately half of the observed variation in tree crown dimensions, we find that local, ecosystem, and phylogenetic predictors account for the half of the residual variation. Crown scaling does not change significantly across regions, but does change across ecosystem types, where savanna tree crowns grow more quickly with tree girth than forest tree crowns. Crowns of legumes were wider and more voluminous than those of other taxa. Thus, while MST can accurately describe the central tendency of tree crown size, local ecological conditions and evolutionary history appear to modify the scaling of crown shape. Importantly, our extension of MST incorporating these differences accounts for the mechanisms driving variation in the scaling of crown dimensions across the tropics. We present allometric equations for the prediction of crown dimensions across tropical ecosystems. These results are critical when scaling the function of individual trees to larger spatial scales or incorporating the size and shape of tree crowns in global biogeochemical models.
- Subjects :
- 0106 biological sciences
Tree allometry
Variation (game tree)
Environmental Science (miscellaneous)
010603 evolutionary biology
01 natural sciences
allometry
Ecosystem
tropical trees
lcsh:Forestry
Scaling
lcsh:Environmental sciences
Nature and Landscape Conservation
lcsh:GE1-350
Global and Planetary Change
tree crowns
Ecology
Phylogenetic tree
Crown (botany)
Elevation
Forestry
15. Life on land
Metabolic Scaling Theory
Tree (data structure)
Taxon
Geography
tree architecture
lcsh:SD1-669.5
Allometry
Physical geography
010606 plant biology & botany
Subjects
Details
- Language :
- English
- Volume :
- 3
- Database :
- OpenAIRE
- Journal :
- Frontiers in Forests and Global Change
- Accession number :
- edsair.doi.dedup.....ca1ae2135403434d01ac439aea4eeebf