Volume and Value Growth of Hardwood Trees in Wisconsin

Abstract

Abstract The volume of healthy trees of commercial size in the maple-birch forest type measured during the last two Forest Inventory Analysis surveys of Wisconsin grew at 2 to 3%/yr for sawtimber, and 3 to 4% for poletimber, with substantial differences among species. However, from 1967 to 1989, the real price of logs decreased or remained constant for most grades and species. The decrease was especially large for high grade logs. The only exceptions were red oak and elm, whose prices increased at 1 to 2%/yr, for all grades. As a result, the average value growth rate of the trees that did not improve in grade was a modest 2%/yr, and not different from zero at a 5% significance level. Holding high grade trees led to substantial losses. Red oak and elm provided good returns because of favorable price trends, and quaking aspen because of its fast volume growth. Among the worst financial performers were hard and soft maple and yellow birch, the most numerous trees in the sample. A simple equation was derived to predict volume growth rates as a function of tree diameter, site index, crown ratio, stand basal area, crown dominance, and tree species. Although these variables did influence volume growth, suggesting that silvicultural practices could be beneficial, they explained only a small part of volume growth, and less of value growth. The future of commercial forestry in Wisconsin depends at least as much on policies that will develop markets and obtain good prices as on improved silviculture. North. J. Appl. For. 10(2): 63-69.