Biomass and nutrient distributions in central Oregon second-growth ponderosa pine ecosystems.

Abstract

We investigated the distribution of biomass and nutrients in second-growth ponderosa pine (Pinus ponderosa Dougl. ex Laws.) ecosystems in central Oregon. Destructive sampling of aboveground and belowground tree biomass was carried out at six sites in the Deschutes National Forest; three of these sites also were intensively sampled for biomass and nutrient concentrations of the soil, forest floor, residue, and shrub components. Tree biomass equations were developed that related component biomass to diameter at breast height and total tree height. No significant differences in equation coefficients were detected among sites, thereby allowing a pooling of the data for equations predicting dry weights for boles, crowns, bark, and coarse roots. Nutrient concentrations were highest in the foliage of trees and in the shrub component and lowest in the soil component. Total nutrient content, however, was greatest in the soil component. Assessment of the nutrient distributions suggests that bole-only harvesting and debarking onsite will result in the greatest retention of tree nutrients within the ecosystem.

Citation

Little, Susan N.; Shainsky, Lauri J. 1995. Biomass and nutrient distributions in central Oregon second-growth ponderosa pine ecosystems. Res. Pap. PNW-RP-481. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 17 p