Drought Watch: The state of the forests in Summit County
Special to the Daily
Editor’s note: This is the second in a multi-part series submitted by local forest and fire experts addressing the impact of the drought on wildfire, water supply, recreation and Summit County’s forests. The series appears on Friday’s in the Daily.
Late summer 2012. It’s the middle of the day, hot and dry. The intense high-elevation sun beats down relentlessly. The soil beneath our feet is hot to the touch. We’re volunteers. Our job is to help monitor forest regeneration in an area where trees were harvested several years back to reduce wildfire danger and foster new growth. We carefully count the seedling trees and question how many can survive given the National Weather Service has identified the last decade as the hottest and driest on record.
Here at home in Summit County, we’ve experienced big changes in our forested landscape over the last decade. We are now accustomed to seeing dead trees scattered across our forested mountain slopes. What happened and what is the state of the forests in Summit County today?
Summit County’s forests are composed of a variety of species having a natural ability to withstand periods of drought. But persistent drought has a dramatic impact on forest structure by weakening individual trees and making them susceptible to insect attack, disease and decline. Our most recent drought began around 2000. Stressed forest conditions were evidenced by the subsequent mountain pine beetle outbreak that swept through Summit County between 2002 and 2009. In short order, the lodgepole pine forest landscape moved from mature even-aged trees to a regenerating forest with vast areas of dead trees.
Although tree mortality was widespread, not all trees were affected by the mountain pine beetle outbreak. A mosaic of stands withstood the epidemic and these can be seen as islands of green trees mixed in along the lower slopes and valleys. In areas of beetle-killed trees, grasses, forbs, other tree species and lodgepole seedlings are beginning to emerge. Existing seedlings and saplings are flourishing with the added sunlight reaching the forest floor through the once dense canopy. The future forest is emerging.
Summit County’s upper elevation forests consist of Engelmann spruce and subalpine fir, commonly called spruce-fir forests. The spruce-fir forests are also susceptible to insects, disease and decline during persistent drought. According to the 2012 Report on the Health of Colorado Forests, released by the Colorado State Forest Service, the most recent assessment of Summit County’s spruce-fir forests is good. Aerial flight surveys performed in the summer of 2012 did not indicate any significant insect, disease or decline activity in these upper elevation forests. Most of the spruce-fir forests are mature and typically have a longer period of natural disturbance.
The Dillon Ranger District is responsible for over 300,000 wild-land acres in the most heavily used national forest in America. Publicly owned USFS land accounts for over 75 percent of the total area of Summit County. The Forest Service seeks to manage this landscape in a manner that promotes health and sustainability of the ecosystem, while protecting interests of the community, visitors and residents. Improving the condition of forests, watersheds and wild-lands we depend on for recreation, jobs and quality of life is a priority.
Higher temperatures and reduced precipitation over the last decade have contributed to a dramatic increase in forest mortality due to insects, disease and decline. Replacement of mature forests with re-growth of seedlings and saplings has been initiated. What we may have viewed as the death of our forests can now be seen as a rebirth.
Cary Green is a forester with the U.S. Forest Service.
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