Relationship Between Volume and Biomass of Early Successional Vegetation and the Prediction of Loblolly Pine Seedling Growth

Abstract

Abstract A simple and nondestructive method of measuring plant volume was developed to test the following two hypotheses: (1) plant volume is an effective substitute for plant biomass in the prediction of competitive potential; and (2) the plant biomass-volume relationship is affected by plant growth form. In 1983, above-ground volume and biomass were determined for all plants in 40 1-m² plots in an experimental loblolly pine (Pinus taeda L.) plantation having varying degrees of successional regrowth. After natural log transformations of plant biomass and volume, separate regression equations were developed for grass, forb, shrub, and tree growth forms. A test of homogeneity indicated that the slopes and intercepts for the four regression equations were not all identical. Specific contrasts among the regression equations were also tested for common slopes and intercepts to determine the source of overall significance. Results of the contrasts were explained by differences in plant allocation patterns. The variation in plant biomass accounted for by the volume models ranged from 78% for grasses to 94% for trees. As an application of this approach, volume was measured and biomass was estimated from the regression equations for successional plants within a 2m radius (the "neighborhood") of each of 69 loblolly pine seedlings. Total plant volume and total estimated biomass each accounted for approximately 40% of the variation in pine growth. For. Sci. 34(4):939-947.