Evaluation of Region and Subregion-Based Total Volume Equations for Dahurian Larch in Northeast China

Abstract

A total of 10 sub-regions were identified and tree total volume equations were developed for economically important Dahurian larch species in northeast China (Daxing'an Mountain region/Heilongjiang province). These equations were based on a simple power function and adjusted to the forest inventory data volumes of three mountainous regions, including the northwest of northern slope of Yilehuli Mountains (NWYLHLM), the southeast of northern slope of Yilehuli Mountains (SAYLHLM) and the eastern slope of northern part of Daxin'an Mountains (NDXAM). The volume equations were tested to determine if differences by ecoregion were statistically significant. Results varied by species, volume and ecoregion suggesting that the relationship between tree volume and tree diameter of Dahurian larch (Larix gmelinii Rupr) tree species is significantly different between the three geographic regions, depending on local climatic, soil and ecological conditions. This implies that the provincial and regional models of volume-diameter relationships are not appropriate for predicting tree volume at ecoregional level. In addition, the use of an ecoregional specific model will lead to significant bias in predicting the total volume of trees. The ecoregion-based volume models developed in this study could provide more accurate information on tree growth and development to forest resource managers and planners.