Nitrogen Productivity of Alaskan Tree Species at an Individual Tree and Landscape Level

The nitrogen-productivity (N-productivity) concept represents one approach for development of algorithms for expansion from the individual tree to stand or landscape levels of estimation of primary production across the Earth’s surface. A simple equation based on the N-productivity concept can be used to estimate plant production from the individual tree to stand level geographic units. Maximum N-productivity equations were developed for balsam poplar, white birch, and white spruce on an individual tree basis for the taiga of interior Alaska. Maximum N-productivity equations were also developed for aspen, balsam poplar, and white spruce on a unit area basis (square meters). A single equation for all species sampled and individual stands was developed on a unit area basis. The calculated productivity for test stands was in close agreement to the measured productivity from the landscape perspective. The set of equations presented can be used for calculation of taiga forest productivity in a geographic model developed within a GIS (Geographic Information System) software package in which the landscape unit is an integral part of the model structure.