MIXED-CONIFER FOREST
; STAND-REPLACING FIRE
; COMPETING VEGETATION CONTROL
; NORTHERN SIERRA-NEVADA
; PONDEROSA PINE FORESTS
; CALIFORNIA SPOTTED OWL
; ASSISTED GENE FLOW
; HIGH-SEVERITY FIRE
; SPATIAL-PATTERNS
; TREE MORTALITY
WOS学科分类:
Forestry
WOS研究方向:
Forestry
英文摘要:
The increasing frequency and severity of fire and drought events have negatively impacted the capacity and success of reforestation efforts in many dry, western U.S. forests. Challenges to reforestation include the cost and safety concerns of replanting large areas of standing dead trees, and high seedling and sapling mortality rates due to water stress, competing vegetation, and repeat fires that burn young plantations. Standard reforestation practices have emphasized establishing dense conifer cover with gridded planting, sometimes called 'pines in lines', followed by shrub control and pre-commercial thinning. Resources for such intensive management are increasingly limited, reducing the capacity for young plantations to develop early resilience to fire and drought. This paper summarizes recent research on the conditions under which current standard reforestation practices in the western U.S. may need adjustment, and suggests how these practices might be modified to improve their success. In particular we examine where and when plantations with regular tree spacing elevate the risk of future mortality, and how planting density, spatial arrangement, and species composition might be modified to increase seedling and sapling survival through recurring drought and fire events. Within large areas of contiguous mortality, we suggest a "three zone" approach to reforestation following a major disturbance that includes; (a) working with natural recruitment within a peripheral zone near live tree seed sources; (b) in a second zone, beyond effective seed dispersal range but in accessible areas, planting a combination of clustered and regularly spaced seedlings that varies with microsite water availability and potential fire behavior; and (c) a final zone defined by remote, steep terrain that in practice limits reforestation efforts to the establishment of founder stands. We also emphasize the early use of prescribed fire to build resilience in developing stands subject to increasingly common wildfires and drought events. Finally, we highlight limits to our current understanding of how young stands may respond and develop under these proposed planting and silvicultural practices, and identify areas where new research could help refine them.
1.Univ Calif Davis, Dept Plant Sci, Davis, CA 95616 USA 2.Univ Calif Berkeley, Environm Sci Policy & Management Dept, Berkeley, CA 94720 USA 3.US Geol Survey, New Mexico Landscapes Field Stn, Santa Fe, NM 87508 USA 4.Humboldt State Univ, Dept Forestry & Wildland Resources, Arcata, CA 95521 USA 5.US Forest Serv, USDA, Sierra Cascade Reg Ecol Program, Quincy, CA 95971 USA 6.US Forest Serv, USDA, PSW Res Stn, Redding, CA 96002 USA 7.Tahoe Reg Planning Agcy, Stateline, NV 89449 USA 8.US Forest Serv, USDA, Quincy, CA 95971 USA 9.US Forest Serv, USDA, Cent Sierra Reg Ecol Program, Placerville, CA 95667 USA 10.Utah State Univ, Dept Watershed Sci, Logan, UT 84321 USA 11.US Forest Serv, USDA, PSW Res Stn, Davis, CA 95618 USA 12.US Forest Serv, USDA, Southern Sierra Reg Ecol Program, Bishop, CA 93514 USA 13.Univ Calif Davis, ARS, USDA Calif Climate Hub, Davis, CA 95616 USA 14.US Forest Serv, USDA, Reg Ecol Program, Vallejo, CA 94592 USA 15.Univ Calif Davis, Dept Environm Sci & Policy, Davis, CA 95618 USA 16.US Forest Serv, USDA, Georgetown, CA 95634 USA
Recommended Citation:
North, Malcolm P.,Stevens, Jens T.,Greene, David F.,et al. Tamm Review: Reforestation for resilience in dry western US forests[J]. FOREST ECOLOGY AND MANAGEMENT,2019-01-01,432:209-224