气候变化领域集成服务门户(CCPortal): Ecological niches of tree species drive variability in conifer regeneration abundance following fuels treatments

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DOI	10.1016/j.foreco.2020.118475
	Ecological niches of tree species drive variability in conifer regeneration abundance following fuels treatments
	Fialko K.; Ex S.; Wolk B.H.
发表日期	2020
ISSN	0378-1127
卷号	476
英文摘要	One goal of fuels treatments is to limit potential fire behavior by reducing overstory tree density, but this may precipitate regeneration, which contributes to increasing potential fire behavior over time. To understand factors that influence tree regeneration in treated stands, we compared abundance of advance and post treatment regeneration in 5–14-year-old thinning and mastication treatments covering approximately 2600 ha within two National Forests in Colorado, U.S.A. The study sites were dominated by two species with complimentary regeneration niches. Ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) is less shade tolerant, but more fire and drought resistant than Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). We considered three critical features of the post treatment environment: species composition, forest structure (especially density), and site characteristics. Regeneration densities at the plot level varied considerably: 37% of the plots had no regeneration, while 15% had more than double the average density. High-density areas tended to occur in moist sites, mostly on north aspects that were dominated by Douglas-fir in the overstory. These areas are where wildfire mitigation benefits will likely deteriorate most rapidly. The vast majority (69%) of all regeneration was Douglas-fir. 31% of all regeneration occurred post treatment. In this group, ponderosa pine abundance was positively related to time since treatment but Douglas-fir was not, suggesting a stronger positive effect of treatment for ponderosa pine, although Douglas-fir was still more abundant. This is likely because treatments reduced the seed source for Douglas-fir more than for ponderosa pine while reducing total overstory density to create conditions that met the regeneration requirements of this shade intolerant species. Advanced regeneration was common throughout the study area, consisting of nearly 80% Douglas-fir and only 13% ponderosa pine. Although the abundance of advance regeneration decreased over time since treatment, likely due to mortality given that we encountered few sapling-sized trees, surviving trees reduce treatment longevity and have the potential for subsequent growth release and contribution to fuel hazard development. Conifer regeneration did not vary between mastication and thinning treatments. The impact of regeneration on treatment longevity was highly variable at smaller-than-stand scales. On the Colorado Front Range, moist sites with low overstory density and mature Douglas-fir to provide a seed source are where treatment effectiveness is likely to degrade most rapidly. These areas with abundant regeneration may be best left untreated, or managers should anticipate the need to re-treat them more frequently. © 2020
英文关键词	Advance regeneration; Douglas-fir; Fuel hazard reduction; Fuels treatment effectiveness; Ponderosa pine; Regeneration niches
语种	英语
scopus关键词	Drought; Fuels; Mastication; Advance regenerations; Advanced regeneration; Colorado Front Range; Critical features; Pseudotsuga menziesii; Site characteristics; Species composition; Thinning treatment; Reforestation; abundance; coniferous tree; drought; fire behavior; overstory; regeneration; shade tolerance; thinning; wildfire; Density; Drought; Fires; Fuels; Pinus Ponderosa; Processing; Pseudotsuga Menziesii; Reforestation; Colorado; Front Range; Rocky Mountains; Coniferophyta; Pinus ponderosa; Pseudotsuga; Pseudotsuga menziesii
来源期刊	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154995
作者单位	Colorado State University, Department of Forest and Rangeland Stewardship, Fort Collins, CO 80523-1472, United States; Colorado Forest Restoration Institute, Colorado State University, Fort Collins, CO 80523-1472, United States
推荐引用方式 GB/T 7714	Fialko K.,Ex S.,Wolk B.H.. Ecological niches of tree species drive variability in conifer regeneration abundance following fuels treatments[J],2020,476.
APA	Fialko K.,Ex S.,&Wolk B.H..(2020).Ecological niches of tree species drive variability in conifer regeneration abundance following fuels treatments.Forest Ecology and Management,476.
MLA	Fialko K.,et al."Ecological niches of tree species drive variability in conifer regeneration abundance following fuels treatments".Forest Ecology and Management 476(2020).