Abstract
Stand structure affects two key variables that affect biomass allocation to the stem: leaf area and height to the center of the crown. By translating wind forces into bending moment, these variables generate bending stress within a stem. The uniform stress axiom of stem formation can be used to calculate current stem mass for a given bending moment and stem allocation for changes in bending moment over a time period. Stem allocation probably affects allocation to fine roots since the stem precedes the root system on the chain of carbohydrate sinks, and total net primary production is a linear function of leaf area. This study indirectly supports this link between stand structure and belowground allocation. A regression model based on the relationship between bending moment and stem allocation explained 98% of the variation in stand level stem production of a 12-yr-old loblolly pine (
Pinus taeda L.) plantation subjected to factorial combinations of irrigation and fertilization. Furthermore, relative fine-root allocation was inversely related to relative stem allocation and increases in apparent bending stress. Corresponding associations between bending stress and relative allocation between the stem and fine roots appear to exist for other species, providing additional support for the proposed link.
Keywords
Pinus taeda,
uniform stress axiom,
carbon allocation,
fertilization
Citation
Dean, Thomas J. 2001. Potential effect of stand structure on belowground allocation. Forest Science 47(2001):69-76
