Above-ground biomass and nutrient distribution of released and fertilized yellow-poplar trees

A study was established to evaluate the effects of release and fertilizer treatments on above-ground biomass and nutrient distribution of 10-year old yellow-poplar (Linodendron tulipifera L.) saplings in Virginia. Treatments were applied in the spring of 1989 and again in 1992. Growth was evaluated over seven growing seasons, 1989 to 1995. About 71% of the biomass of IS-year old trees was bole wood, and 11% bark. Foliar biomass was 5.7% of the total. The nutrient distribution differed somewhat by treatment, with significant responses to both release and fertilization. Overall, foliage had the highest nutrient content, containing 39% of total tree N. Bole wood, due to its larger mass, contained from 42 to 55% of above-ground nutrients. Release resulted in a significant(P < 0.01) biomass growth response after seven years. All biomass components appeared to respond to release, while fertilizer had no significant effect, although all components were also slightly higher than controls for the fertilized trees. Release significantly increased light levels penetrating the canopy. The increased growth due to the release treatment was most likely caused by this increased light, which stimulated a 40% increase in foliar biomass after seven years. (C) 1998 Elsevier Science B.V.