Nature and science
When caterpillars removed the canopy: measuring carbon in 2007
Documented history and research · Sources compared
A defoliation outbreak became a test of how researchers measure a forest’s carbon balance when its leaves disappear.
Three years with different canopies
Kenneth Clark, Nicholas Skowronski and John Hom compared oak- and pine-dominated forests across 2005, 2006 and 2007. The first year had little defoliation. A mixed stand was partly defoliated in 2006; in 2007 an oak-dominated stand lost its canopy completely while the other stands experienced partial damage. The changing conditions supplied a before-and-during comparison. Clark, Skowronski and Hom (2010).
Their 2010 paper combined eddy-covariance measurements of carbon dioxide exchange with measurements of vegetation. The insects were identified as Lymantria dispar, now generally called spongy moth; the source uses the older common name. The study treated herbivory as an ecosystem disturbance with consequences beyond the immediate sight of bare branches. Clark, Skowronski and Hom (2010).
A model checked against measurements
A companion study by Karina Schäfer and colleagues estimated canopy carbon assimilation using sap-flow measurements through whole trees and gas exchange at different canopy levels. The researchers first evaluated the model against 2006 eddy-flux measurements. They then applied it to 2005 and to the two-to-three-week period of complete defoliation in 2007. Schäfer and colleagues, canopy assimilation model (2010).
This pairing matters because the atmosphere-facing instruments and the tree-based model approached the same forest from different directions. Neither an empty canopy photograph nor a tally of defoliated acres alone supplies a complete carbon budget. The inspected abstracts establish the comparison and methods; exact annual losses require the full results, so no numerical carbon-loss total is assigned here. Schäfer and colleagues, canopy assimilation model (2010).
Sources and research limits
- Clark, Skowronski and Hom (2010) — Institutional abstract and bibliography read; PDF retrieval failed.
- Schäfer and colleagues, canopy assimilation model (2010) — Institutional abstract and methods summary read.
These are related investigations of an outbreak, not independent replications at unrelated sites. The narrative explains the documented experiment without inventing results unavailable in the inspected abstracts.