Canadian Forest Service Publications

Ecology of shore pine stands infested with dwarf mistletoe on southeastern Vancouver Island. 1976. Wass, E.F. Government of Canada. Department of the Environment. Canadian Forest Service, Pacific Forest Research Centre, Victoria, BC. Information Report BC-X-142. 33 p.

Year: 1976

Issued by: Pacific Forestry Centre

Catalog ID: 1763

Language: English

Series: Information Report (PFC - Victoria)

Availability: PDF (download)

Mark record


The dwarf mistletoe occurring on shore pine (Pinus contorta var. contorta) in Coastal British Columbia is classified as Arceuthobium tsugense, a mistletoe that principally parasitizes western hemlock (Tsuga heterophylla). Shore pine is considered its secondary host.

A detailed study of infestations on S.E. Vancouver Island indicated that dwarf mistletoe intensity on the shore pine was extremely high. An average of 85% of trees over 1.4 m were infected and the average stand infection intensity ranged from 0.7 to 5.1 on a 6-class system.

Most infection centers were located in the Coastal Douglas-fir Zone on mountain tops consisting of a mosaic of plant communities of forest on lithosols and rocky knolls. Vegetation was dominated by Pinus contorta var. contorta, Pseudotsuga menziesii, Arbutus menziesii, Salix scouleriana, Gaultheria shallon, Arctostaphylos columbiana, Holodiscus discolor and Arctostaphylos uva-ursi.

The study showed that A. tsugense on shore pine flourishes on habitats separated from A. tsugense on hemlock. Separation of the two would favor maintenance of the physiological differentiation indicated by earlier cross-inoculation experiments.