Two decades of variable retention in British Columbia: a review of its implementation and effectiveness for biodiversity conservation  

作　　者：William J.Beese John Deal B.Glen Dunsworth Stephen J.Mitchell Timothy J.Philpott 

机构地区：[1]Vancouver Island University,900 Fifth Street,Nanaimo,BC V9R 5S5,Canada [2]Western Forest Products,118–1334 Island Hwy.,Campbell River,BC V9W 8C9,Canada [3]Glen Dunsworth Ecological Consulting,7857 Shangri-La Rd.,Lantzville,BC V0R 2H0,Canada [4]University of British Columbia,2424 Main Mall,Vancouver,BC V6T 1Z4,Canada [5]BC Min.of Forests,Lands and Nat.Res.Oper,400–640 Borland St.,Williams Lake,BC V2G 4T1,Canada

出　　处：《Ecological Processes》2019年第1期402-423,共22页生态过程（英文）

基　　金：by the Province of British Columbia(BC Ministry of Forests,Lands,Natural Resource Operations and Rural Development;BC Forest Investment Account,Land Based Investment Program;BC Forest Science Program),the University of British Columbia and forest companies(Cascadia Forest Products,MacMillan Bloedel Limited,Western Forest Products Inc.,Weyerhaeuser Company).Other than the scientists and field personnel directly involved in the research,the funding bodies did not have a role in the design of the studies,in the collection,analysis,and interpretation of data,and in writing the manuscript.

摘　　要：Stand-level retention is an important component of sustainable forest management which aims to balance ecological,social and economic objectives.Long-term retention of mature forest structures at the time of harvesting(variable retention)is intended to produce future forest stands that more closely resemble conditions that develop after natural disturbances,thereby maintaining greater diversity of habitats for a variety of organisms.Structure includes features such as live and dead trees representing multiple canopy layers,undisturbed understory vegetation and coarse woody debris.Over the past two decades,variable retention has become common on forest lands in the temperate rainforests of coastal British Columbia(BC)and has been applied to a lesser extent in inland forest types.Our review of studies in BC and in similar forest types in our region indicates that both aggregated and dispersed retention can contribute to biodiversity conservation by providing short-term‘life-boating’habitat for some species and by enhancing the structural characteristics of future stands.For example,greater abundance of species present in the pre-harvest forest have been documented for vegetation,birds,carabid beetles,gastropods,ectomycorrhizal fungi and soil fauna in retention cutblocks compared to clearcuts.There are,however,some negative consequences for timber production such as wind damage to retained trees and reduced growth rates of tree regeneration compared to clearcuts.The authors suggest an adaptive management approach for balancing competing objectives when faced with uncertainty.This includes monitoring the implementation and effectiveness of various strategies for achieving goals.Over two decades of experience applying variable retention harvesting to industrial-scale management of forest lands in BC suggests that it is possible to balance production of wood with biodiversity conservation.

关 键 词：Alternative silvicultural systems CLEARCUTTING Biological legacies Forest biodiversity OLD-GROWTH Variable retention British Columbia 

分 类 号：S71[农业科学—林学]