Guest: David Peterson
David Peterson (Seattle, WA), Biologist, Pacific Wildland Fire Sciences Laboratory, "Air Quality Effects on Humans, Plants and Water"
The second guest, David Peterson, has 28 years experience as a Research Biologist with the Pacific Wildland Fire Sciences Laboratory, run by the U.S. Forest Service.
Regarding global climate change, he explained that forests store carbon that can help reduce greenhouse gasses in the atmosphere. Thus, reforestation (replanting forests that have been removed through logging or land clearing) and afforestation (creating forests where there were none), can be critical to maintaining a healthy global environment and counteracting the effects of increasing human population, land development and pollution.
He noted that an increase in the mountain pine beetle, caused by a dryer climate, has devastated forest populations in British Columbia and Colorado. When trees die off due to drought stress, it creates a vicious circle in which the beetles reproduce in the dead trees and then attack and kill the healthy trees. They can be controlled by removing the affected trees, spraying with pesticides and creating more rain.
This is similar to the gypsy moth invasion in the 1970's and 80's, which devastated vast areas of the Pacific Northwest and Rockies. In that case, the invasion simply ran its course and the forests recovered after a few years. Many of the defoliated trees, thought to be dead, managed to pull through.
On the other hand, if you have nothing but wall-to-wall mature forests with no openings (openings are caused by diseases, wildfire, landslides, etc), that creates a poor environment for large mammals, tree reproduction and genetic diversity.
Categories: Ecology and the environment, global warming and climate change