PARENT SESSION
Oral Session #54: Fire Ecology -- Trees, forests, woodlands.
Presiding: E. Menges
Wednesday, August 7. 8:00 AM to 11:30 AM. Apache Meeting Room, TCC.
Old growth ponderosa pine and western larch respond positively to restoration thinning and burning treatments.
SALA, ANNA*,1, HARRINGTON, MICHAEL2, DELUCA, THOMAS3, CALLAWAY, RAGAN1, 1 Division of Biological Sciences, Missoula, Montana2 USDA FS Rocky Mountain Research Station, Missoula, Montana3 School of Forestry, Missoula, Montana
ABSTRACT- In the interior northwest, harvesting of old growth trees and fire exclusion since the early 1900's has resulted in a successional replacement of open ponderosa pine and western larch stands to stands of interior Douglas-fir. There is a strong interest to actively manage old growth stands in the Northern Rocky Mountains to restore then to pre-settlement conditions and to protect them from harvesting, severe wildfire and stress-induced mortality. However, little is known on the responses of old growth trees to alternative management practices. We examined the effectiveness of several restoration treatments to ameliorate soil resource availability and improve the function of old growth ponderosa pine and western larch in western Montana. The treatments applied were: 1) untreated control, 2) understory cutting followed by pile burning, 3) understory cutting followed by broadcast burning, 4) overstory thinning with understory cutting followed by pile burning and 5) overstory thinning with understory cutting followed by broadcast burning. Two years after treatment implementation, western larch in treated plots had significantly higher whole-tree water use and increased foliar nitrogen content relative to trees in control plots. Ponderosa pine in treated plots also exhibited higher water use and significant increases in foliage production relative to control plots. While we observed a strong positive effect of the understory removal on the overstory old growth trees, differences in soil resource availability and tree performance between restoration treatments were small.
KEY WORDS: Pinus ponderosa, Larix occidentalis, Restoration Management, Fire