科研之友
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摘要
The net value of hardwood trees (dollars per tree) is thought to increase with stem size for three reasons. First, large trees yield a greater volume (cubic meters) of logs, which tend to be larger than logs from small trees; second, large logs are more valuable (dollars per cubic meter) than small logs; and, third, large logs cost less (dollars per cubic meter) to process than small logs. Yet few studies have assessed both the cost of processing hardwood trees and the value of their products. In this article, we examine how the net value of sugar maple trees (Acer saccharum) varies with tree size and the presence of defects, such as fungi and seams. We quantify the gross value of firewood, lumber, and residues as well as the costs of harvesting and sawmilling. For each tree, we also calculate its net value to an integrated forestry company by subtracting costs from gross values. Our results confirm that large trees are more profitable than small trees but challenge current assumptions as to why. As expected, the volume and value of products are reduced by defects, while costs (dollars per cubic meter) are lower for larger trees. However, we found that gross value (dollars per cubic meter) does not vary with tree size, indicating that large trees yield more but not necessarily better products. The results of this study provide insight into how loggers can improve value recovery while limiting processing costs. These results also challenge the rationale behind silvicultural prescriptions that retain large trees based on the assumption that they produce greater volumes of higher-quality wood.
- 出版日期2014
