Abstract
A functional¿structural plant growth model was used to explore how selection
might influence the ontogenetic patterns in three-dimensional (3-D) growth of trees. The 3-D
plant structure is defined by the orientation of metamers. The dynamics in the 3-D plant
structure depend on the production of metamers and/or leaf pipes and the loss of such plant
components. In the simulations, metamer and leaf-pipe traits were kept constant, so all
ontogenetic changes depended on the spatial arrangement of metamers and/or leaf pipes. This
study explores the consequences of three new assumptions for ontogenetic changes in 3-D
plant structure: (1) meristems are produced at the positions where branches fall, thus enabling
a tree to maintain a viable meristem population within the crown; (2) metamers are placed at
meristem positions in the 3-D structure where the carbon benefit over the expected life span of
a leaf pipe is maximized; (3) the carbon allocation to reproduction maximizes the long-term
reproductive output. In combination with the constraints set by the morphology of metamer
and leaf pipe, the carbon economy, and light conditions, these assumptions explain how
selection may cause a sigmoid expansion phase and a stable steady-state phase; adaptive
responses in 3-D structure during ontogeny; limits to tree size (including height); constant
allometric scaling during the expansion phase; different scaling for trees in different light
environments; and responses in optimal reproductive allocation to forest light environments.
These results support the idea that selection for maximizing the net carbon gain determines
how trees change in 3-D tree structure during ontogeny and, at the same time, how they
acclimate in 3-D structure in response to light gradients
Original language | English |
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Pages (from-to) | 405-420 |
Journal | Ecological Monographs |
Volume | 77 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2007 |
Keywords
- life-history variation
- rain-forest trees
- crown architecture
- understory plants
- self-organization
- apical dominance
- height growth
- light capture
- woody-plants
- trade-offs