Skip to main content
U.S. flag

An official website of the United States government

Indirect effects of bark beetle-generated dead wood on biogeochemical and decomposition processes in a pine forest


Courtney M. Siegert
Natalie A. Clay
Lisa G. Garrigues
John J. Riggins



Publication type:

Scientific Journal (JRNL)

Primary Station(s):

Southern Research Station


Oecologia. 188(4): 1209-1226.


Bark beetle outbreaks are increasing in frequency and intensity, generating massive inventories of dead trees globally. During attacks, trees are pre-inoculated with ophiostomatoid fungi via bark beetles, which has been shown to increase termite presence and feeding. These events may, in turn, alter biogeochemical cycles during decomposition. We examined these relationships by experimentally inoculating dead wood with bluestain fungi in a temperate pine forest. Across ten replicate plots, eight 0.5 m-long logs were inoculated with Ophiostoma minus and eight with distilled water. Half of the logs from each inoculation treatment were covered from above with a mesh cage barrier to exclude aboveground beetles while permitting access by belowground decomposers. After 1 year, signifcant increases in mass (34%) and decreases in moisture content (− 17%) were observed across all treatments, but no consistent changes in density were evident. C concentrations were 12% greater in bark when barriers were present and 17% greater in sapwood when barriers and inoculation fungi were absent. N concentrations were 16% greater in bark for fungal-inoculated logs and 27% greater when barriers were present. C:N ratios in A horizon soils under fungal-inoculated logs were 12% greater. Furthermore, termites were present fourfold more in fungal-inoculated logs than controls and the presence of termites was associated with 6% less C in sapwood and 11% more N in both sapwood and heartwood. Together these results suggest dead wood generated via bark beetle attacks has diferent biogeochemical responses during initial decomposition phases, which could have implications for the C status in forests following bark beetle outbreaks.


Siegert, Courtney M.; Clay, Natalie A.; Tang, Juliet D.; Garrigues, Lisa G.; Riggins, John J. 2018. Indirect effects of bark beetle-generated dead wood on biogeochemical and decomposition processes in a pine forest. Oecologia. 188(4): 1209-1226.


Publication Notes

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.