气候变化领域集成服务门户(CCPortal): Effects of small aggregates of mature tree retention on adjacent planted coastal Douglas-fir growth and survival

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DOI	10.1016/j.foreco.2020.118613
	Effects of small aggregates of mature tree retention on adjacent planted coastal Douglas-fir growth and survival
	Smith N.J.; Beese W.J.
发表日期	2021
ISSN	0378-1127
卷号	480
英文摘要	Long-term retention of mature trees at the time of harvesting, called variable retention, has increased significantly since the 1990s as a silvicultural practice for maintaining stand-level biodiversity. A common approach is aggregated retention where groups of trees are left to increase structural diversity and provide forest influence over the adjacent harvested area. Despite the increased global application of aggregated retention, the growth and survival of adjacent trees has received less research effort than biodiversity studies. This knowledge gap was addressed with a study of small (0.01 to 0.58 ha, mean 0.3 ha) retained mature tree aggregates in harvested areas on southeast Vancouver Island, British Columbia, Canada. Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco.) seedlings were planted in ~10-m-wide belt transects (three planting rows), extending up to 10 m into and 50 m away from aggregate edges in four cardinal directions. Nitrogen fertilizer was applied at planting to some transects. Basal diameter, height and survival of the planted Douglas-fir were measured for an average of 11 years. We used nonlinear mixed-effects models to assess the relationships of planted-tree basal diameter and height growth to distance from aggregate edge, edge orientation, planted-tree age, fertilization and aggregate characteristics (basal area and height). We extended planting into the aggregates to model tree response on both sides of edges. Modeled growth rates were slower for 10-year-old planted trees under the aggregate canopy and along the edges of the harvested area compared to growth at about 10 m and greater distance from aggregate edges; i.e. trees achieved 90% of their potential height and diameter by about 10 m from the aggregate canopy. Impacts were greatest on north-facing edges and least on south-facing edges, although differences were very small. We examined planted-tree survival by proximity to aggregate edges using a Cox proportional hazards model. Survival was lower directly beneath the aggregate canopy and up to approximately 5 m into the harvested area and was also slightly lower adjacent to south-facing edges. Fertilized trees showed a minor increase in survival versus unfertilized trees. Structural characteristics of aggregates had only a minimal impact on planted-tree growth and survival. This study helps provide a better understanding of the relationships among planted-tree growth and survival and edge effects for implementation of aggregated retention. © 2020
英文关键词	Aggregated retention; Cox proportional hazards; Cox regression; Edge effects; Forest influence; Nonlinear mixed-effects; Survival analysis; Variable retention
语种	英语
scopus关键词	Aggregates; Biodiversity; Harvesting; Nitrogen fertilizers; Seed; Aggregate characteristics; British Columbia , Canada; Cox proportional hazards models; Nonlinear mixed effects; Pseudotsuga menziesii; Silvicultural practices; Structural characteristics; Structural diversity; Forestry; aggregate size; biodiversity; canopy exchange; coniferous forest; forestry production; growth response; long-term change; maturation; seedling emergence; survival; Biodiversity; Edges; Forestry; Harvesting; Pseudotsuga Menziesii; Survival; Trees; British Columbia; Canada; Vancouver Island; Pseudotsuga; Pseudotsuga menziesii; Pseudotsuga menziesii var. 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/154826
作者单位	Nick Smith Forest Consulting, 3332 Kite Way, Nanaimo, BC V9T 3Z2, Canada; Vancouver Island University, Forestry Department, 900 Fifth Street, Nanaimo, BC V9R 5S5, Canada
推荐引用方式 GB/T 7714	Smith N.J.,Beese W.J.. Effects of small aggregates of mature tree retention on adjacent planted coastal Douglas-fir growth and survival[J],2021,480.
APA	Smith N.J.,&Beese W.J..(2021).Effects of small aggregates of mature tree retention on adjacent planted coastal Douglas-fir growth and survival.Forest Ecology and Management,480.
MLA	Smith N.J.,et al."Effects of small aggregates of mature tree retention on adjacent planted coastal Douglas-fir growth and survival".Forest Ecology and Management 480(2021).