Contrasting patterns of biomass allocation in dominant and suppressed loblolly pine

We investigated above- and below-ground biomass allocation and allometric r elationships of canopy dominant and suppressed loblolly pine (Pinus taeda L .) trees from a range of diameters at breast height (DBH = 3.5-35.6 cm) to determine if shifts in allocation may influence the growth and persistence of suppressed toes in the understory. Using mass and volume conversions fro m harvested trees (15 dominant and 15 suppressed), we developed regressions to predict total and component biomass from DBH. Bole, branch, needle, and total mass differed between dominance categories (ANCOVA, P < 0.10). For a representative size (15 cm DBH), dominant trees allocated 63.4, 13.2, 11.3 , and 12.0% of biomass to bole, branch, needle, and root tissue compared wi th 75.9, 6.7, 5.6, and 11.7% for suppressed trees. At any given DBH, suppre ssed trees were also taller than dominant trees and had a greater porportio n of heterotrophic (bole plus branch plus root mass) to autotrophic (needle mass) tissue. Percent carbon and nitrogen of tissues did not differ betwee n dominance categories. Unlike the increased investment in leaf area observ ed for seedlings and saplings of shade-tolerant species, suppressed lobloll y pine increased allocation to bole mass and height growth. An increase in height for this shade-intolerant species may enable some suppressed individ uals to escape competition for light. However, increased allocation to hete rotrophic versus autotrophic tissue in suppressed trees may confer a cumula tive disadvantage over time because of increased respiratory load.