Details

Autor(en) / Beteiligte

• Weinstein, D.A.
• Laurence, J.A.
• Retzlaff, W.A.
• Kern, J.S.
• Lee, E.H.
• Hogsett, W.E.
• Weber, J.

Titel

Predicting the effects of tropospheric ozone on regional productivity of ponderosa pine and white fir

Ist Teil von

• Forest ecology and management, 2005-02, Vol.205 (1), p.73-89

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2005

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• We simulated forest dynamics of the regional ponderosa pine–white fir conifer forest of the San Bernadino and Sierra Nevada mountains of California to determine the effects of high ozone concentrations over the next century and to compare the responses to our similar study for loblolly pine forests of the southeast. As in the earlier study, we linked two models, TREGRO and ZELIG, to consider both physiological effects within individual trees and competitive interactions within forest communities. We represented regional effects by simulating at three sites in California, Lassen National Park, Yosemite National Park, and Crestline in the San Bernardino Mountains. At each of these locations, we simulated the response to altered pollutant conditions of 0.5, 1.5, 1.75, and 2 times ambient ozone. Of the two major dominant species in this forest, white fir showed little response, but ponderosa pine was predicted to show large effects. Ambient ozone at Crestline (approximately 110 ppm h, and larger than twice the ambient concentration at either of the other sites) was predicted to decrease individual tree carbon budgets by 10%. This effect was predicted to lead to a decrease in ponderosa pine abundance under average climatic conditions by 16% were these concentrations to continue over the next century. A doubling of ozone at Crestline over the next 100 years was predicted to decrease this budget by an additional 11%, leading to a decline in abundance of 41%. Effects at the other sites were predicted to be smaller (effects of current ambient ozone on abundance of 10% at Yosemite and 0% at Lassen) in proportion to the smaller exposures at those sites. Decreases in chronic moisture availability at all three sites were predicted to reduce these effects, particularly if ozone exposures rise.