Doctoral student focuses on forest future

Doctoral student David D'Amore stands next to an epikarst feature on Prince of Wales Island. Epikarst is the eroded surface of limestone bedrock.

What will the next 100 years of forestry bring? USDA Forest Service Soil Scientist Dave D’Amore is trying to answer that question…but cautiously. “You have to be careful making predictions.” Restoration of forests and streams and climate change, including the adaptation of plants, biomass energy, and hydrology, are on the horizon, he said. As glaciers recede and snowpack melts, D’Amore said there are uncertainties about the consequences of such changes on the watersheds, including the large coastal temperate rainforest of southeast Alaska. The decline of yellow cedar is one example of the impact of changing precipitation patterns due to decreased snowpack.

D’Amore, a UAF SNRAS doctoral student studying with Associate Professor of Soils Dave Valentine, presented his research findings at a graduate student seminar at UAF in November.

The Coastal Temperate Rainforest (from northern California to Prince William Sound) is D’Amore’s focus, particularly the Tongass National Forest. Southeast Alaska is best known for its old-growth forests dominated by western hemlock, and large deposits of woody debris on the ground. The Tongass National Forest features six major tree species, fire is rare, and woody debris accumulates leading to large amounts of stored carbon in the forest.

Looking at the region historically, aboriginal use of the forest was limited and of very low intensity. In the early twentieth century logging was selective and limited to the shoreline and valley bottoms. The level of logging increased during the two world wars and concentrated on Sitka spruce due to its value as an aircraft wood. The 1950s found the pulp mill industry conducting extensive clearcutting. As a result, today there are 263,250 hectares of young-growth forest on the Tongass. The rapid regeneration of trees and lack of understory have become a problem for the wildlife and understory diversity in these types of stands, D’Amore said.

Another issue of importance is the abundance of water in Southeast Alaska. With 3,000 to 5,000 millimeters of precipitation per year, there is no lack of moisture. The area has plentiful bogs, forested wetlands, and scrub forest that form a mosaic with more productive forest overstory, D’Amore said. “It’s not all the same forest.”

Remarking on the decline of yellow cedar, he said there are 200,000 hectares of dead trees standing in the Tongass. Even yellow cedar that has been dead for sixty years still has high quality wood. Integrating the need for restoration with getting use out of the wood is important. Determining how to harvest dead trees and plant new yellow cedars will create a template for how to manage other types of trees in a changing climate.

Understanding the role of dissolved carbon is another priority for D’Amore. He and his colleagues at the Pacific Northwest Research Station in Juneau are working to establish predictive models for carbon flux in the watersheds of the coastal temperate rainforest. “Southeast Alaska has the highest area of weighted dissolved organic carbon flux in the world,” he said. Carbon flux is the transfer of carbon from one pool to another. Quantifying the movement of carbon dioxide into and out of the atmosphere is important for understanding carbon sinks and sources.

Most of D’Amore’s work has been accomplished with colleagues in forest pathology and aquatic ecology at the Juneau Pacific Northwest Research Station. “I implore you to create creative partnerships and get out of your shell,” he said. “Establishing partnerships has helped me expand understanding of fundamental components of coastal temperate rainforest ecosystems.”

For further reading, see:

•"Arctic soil reveals climate change clues," SNRAS Science & News, 9/10/08.

•Carbon and carbon research (PDF), SNRAS/AFES Miscellaneous Publication 2004-09.

"Classification of Forested Histosols in Southeast Alaska", by David V. D'Amore and Warren C. Lynn, Soil Science Society of America Journal, 66:554-562 (2002).

• "Soggy Soils and Sustainability: Forested Wetlands in Southeast Alaska" (PDF), by Sally Duncan, Science Findings, issue 41, February 2002.