On the eastern side of the Sierra, ribbons of brilliant gold flow down the mountainside. The color can be seen from miles away. Meadows spread wide covered with vivid yellow-leafed Aspen quaking in a fall breeze. It's the height of the fall foliage season in this part of California.
As I drove down Hwy 89 south of Lake Tahoe past Markleeville and then over Monitor Pass to Hwy 395 each stand of aspen seemed to glow brighter than the last. I wondered if they would be as beautiful for future generations or if our impact on the environment would cause these glorious trees to change in any way.
Quaking aspen (Populua tremuloides) is the most widespread tree species in North America. It provides food for foraging animals and habitat for wildlife. It also acts as a fuel break and retains much more water in the environment than do most conifer species.
High mountain systems, such as the Sierra Nevada, are uniquely sensitive to anticipated global climate changes and act as canaries in the coal mine to provide early signals of significant climate-driven changes. Research in the Sierra Nevada by Pacific Southwest Research Station, which is a USDA Forest Service research organization, shows how vegetation has responded to climate in the past and indicates changes than might be coming in the future over the next decade.
Climate has a profound influence in shaping our environment and natural resources. By looking at tree-ring records of living and ancient wood and pollen lake sediments present climate can be compared to these historic patterns to show climate changes.
Research indicates a complex, unpredictable future for aspen in the West, where increased drought, ozone and insect outbreaks will compete with carbon dioxide fertilization and warmer soils, with unknown cumulative effects. Aspen are valuable in providing moisture in the landscape and habitat and food for wildlife. They are vulnerable in the face of global warming and climate change. Hopefully, we will not lose this wonderful tree in California.
If you're from a part of the country where these trees are native and you miss their fall color there is a new cultivar of Improved Quaking Aspen developed for mild winter areas like ours. It provides a splash of color for areas that are naturally moist like a natural stream or a high water table. They grow 20-30 feet tall and 15 feet wide and spread by underground roots to form a stand.