Within-Stand Spatial Distribution of Tree Mortality Caused by the Douglas-Fir Beetle (Coleoptera : Scolytidae)
Document Type
Article
Journal/Book Title/Conference
Environmental Entomology
Publication Date
2000
Issue
2
Volume
30
First Page
215
Last Page
224
Abstract
The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, causes considerable mortality in Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, forests. Within-stand distribution of mortality was examined in affected stands using geostatistical techniques. A 10 x 10 m grid was established in two 4-ha study sites. Live and beetle-killed host basal area was measured at each node. In a 16-ha stand, a variable-resolution grid was established and the same information collected. The relationship between Douglas-fir basal area and Douglas-fir basal area killed was examined using non-spatially explicit and spatially explicit linear regression models. A positive linear relationship was observed between the variables. Significant spatially explicit models suggest that the relationship is also true at fine scales. Relative variograms were constructed for Douglas-fir basal area before and after the Douglas-fir beetle outbreaks. For the 4-ha sites, increased spatial dependency in the distribution of Douglas-fir basal area was observed as a result of the Douglas-fir beetle outbreak. For the 16-ha site, kriging was used to estimate live Douglas-fir basal area before and after the outbreak to a 10-m resolution and the stand rated for potential mortality illustrating the potential applicability of geostatistical techniques to rating a stand for potential mortality. Cross-validation analysis indicated that although the potential exists for large estimation errors, the majority of the estimates were within acceptable ranges. The study suggests that geostatistical approaches may be suitable to extend our understanding bark beetle ecology and improving the application of extent of mortality models.
Recommended Citation
Negron, J., Anhold J. and Munson, S. (2000). Within-stand spatial distribution of tree mortality caused by the Douglas-fir beetle (Coleoptera : Scolytidae). Environmental Entomology, 30(2): 215-224.
Comments
This article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific written permission of the publisher.
Publisher's PDF and HTML fulltext can be accessed through remote link via BioOne. This article originally appeared in Environmental Entomology.