Tree mortality caused by the western hemlock looper in landscapes of central British Columbia

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作   者：

Alfaro RI;  Taylor S;  Brown G;  Wegwitz E; 

关键词：

forest trees;  Picea glauca;  arthropods;  plant pests;  British Columbia;  forests;  Lambdina fiscellaria;  forest pests;  Canada;  agricultural entomology;  coniferous forests;  Abies lasiocarpa;  Thuja plicata;  mortality;  outbreaks;  Tsuga heterophylla;  Pinopsida;  insect pests;  defoliation; 

期刊名称：

Forest Ecology and Management

i s s n：

0378-1127

年卷期：

1999 年 124 卷 2/3 期

页   码：

285-291

页   码：

摘   要：

An outbreak of the the western hemlock looper (Lambdina fiscellaria lugubrosa) which had started in 1992 caused tree mortality in central British Columbia, Canada, in stands of 4 cover types - western red cedar-fir (Thuja plicata/Abies lasiocarpa),western hemlock (Tsuga heterophylla)-fir, cedar-hemlock and white spruce (Picea glauca)-balsam [Abies balsamea]. Investigations of the outbreak were made in 28 stands in 4 study areas, which represented both the forest types involved and the range of defoliation intensities found (from light to severe). Defoliation and mortality figures are given for alpine fir, hemlock, spruce and cedar. After 4 yr, high levels of tree mortality (51-96% of all trees with diameter at breast height >=7.5 cm) occurred in areas of severe defoliation, classifying this pest as a serious depletion agent of British Columbia forests. Tree mortality occurred rapidly, mostly within 2 yr of the start of the infestation. Equations are provided to allow foresters to determine expected mortality levels with reasonable precision. A higher proportion of mortality occurred on alpine fir than on other species.