Aspen could become too warm for its namesake tree by 2030

At a time when the American public remains largely unconcerned about climate change, the Aspen Center for Environmental Studies has helped develop a tool that could more clearly convey the grim consequences of a warming planet.

One implication is that the environment in Aspen could become too warm by 2030 to support the aspen tree species.

The center’s staff worked with climate scientists from the University of Arizona to develop ForestForecasts.org, a website that shows how 100 species of trees now found in Western states might fare by 2100. The website can be used to see predicted losses in coming decades of iconic aspen trees and subalpine firs in small geographic areas such as the Roaring Fork Valley or in larger landscapes.

A massive database was accumulated to quantify existing locations and amounts of trees in the West. The website shows what could happen to those trees based on the warming created by releases of specific amounts of carbon and other greenhouse gases into the atmosphere.

The worst-case scenario — the path the planet is on — would raise the average temperature in Aspen by 8 to 10 degrees by 2080. The best-case scenario — if warming were curtailed — would lead to a 3-degree increase by 2080.

The average temperature changes would vary around the West, but the implications would be the same.

“In our initial scientific analysis, under the worst-case climate-change scenario, the American West could lose up to 40 percent of its forests,” said Aspen Center for Environmental Studies Forest Programs Director Jamie Werner. “Even in the best-case scenario, we’re still expected to see some loss, but it’s expected to be down in the 15 to 20 percent zone.”

Changes to Aspen-area forests

The worst-case scenario is bleak in the Aspen area. About half of the Roaring Fork watershed consists of subalpine forests, according to Forest Forecasts research. Under the worst-case scenario, the area suitable for those types of trees would be reduced by 90 percent based on the modeling, Werner said. Woodland and shrubland forest types would replace the subalpine forests associated with higher elevations.

Lower Highland Bowl could have Gambel oak, for example, rather than spruce and fir, said Aspen Center for Environmental Studies Chief Executive Officer Chris Lane.

Aspen’s namesake tree, the quaking aspen, would take a drastic hit in a warming world, Forest Forecasts predicted. In the worst-case scenario, there would be an 82 percent reduction in quaking aspen cover by 2080 — a loss of about 17,630 acres in the watershed, Werner said. The model shows aspen trees could be gone from the city of Aspen by 2030.

Even under the best-case scenario, there would be a 36 percent reduction of quaking aspen, or about 7,740 acres, according to the forecast tool.

The loss of spruce forest in the Roaring Fork watershed is expected to be 31 percent at best and 86.5 percent at worst.

website illustrates issue

ForestForecasts.org uses an interactive online tool to make information about forests’ fates jump to life. Animated scenes show how tree cover could retreat up the slopes into constricted areas in the Aspen area over future decades. Users can select tree types and geographic areas.

The Aspen Center for Environmental Studies worked with the University of Arizona scientists since 2013 to present the information in an intriguing and simple way.

“We like to think of ourselves as the storytellers and the communicators of science,” Werner said. “So we were very happy to work with the scientists from the University of Arizona, who are the real climate and forest modelers behind this project.”

The center expanded its range of focus with the project. The renowned Aspen nonprofit typically dives into issues exclusive to the Roaring Fork Valley but realized a broader look was needed on climate change.

“It’s really difficult to talk about changes to our forests without zooming way out,” Werner said.

ForestForecasts.org was unveiled earlier this month, and now Aspen Center for Environmental Studies and the university are spreading the word about it. It’s free and easy to use. Lane and Werner said the hope is that it helps motivate people to get involved on efforts to reduce greenhouse-gas emissions. Not everyone can relate to the melting of glaciers on a warming planet, Werner said, but most people have a connection to trees.

“Most of us have walked through a forest,” she said.

The website illustrates the drastic changes that are expected.

“Our choices today will impact the forest that we will see as early as 2080,” Werner said.

The trick is persuading the American public to take action. A poll conducted by the Associated Press-NORC Center for Public Affairs Research in mid-October showed that two-thirds of Americans believe in global warming and the vast majority believe human activities contribute to the problem. However, fewer than 1 in 4 are extremely or very worried about it, the poll showed.

Loss goes beyond aesthetics

The Aspen Center for Environmental Studies is trying to show that the loss of forests goes beyond altering pretty scenery. A major consequence of losing forests is losing water-storage capacity, Lane said. The high-elevation forests serve as reservoirs for the snowpack. Trees shade the snow, preserve it longer and let it melt out gradually.

To demonstrate that point, Werner noted that the Roaring Fork watershed comprises only 1 percent of the land in the Colorado River Basin, yet it contributes 11 percent of the water that enters Lake Powell.

“If we lose a large part of the spruce-fir forest that makes up that 1 percent of land, the impact on water provision is exponential,” Werner said.

scondon@aspentimes.com