INVESTIGATIONS OF DECAY IN WESTERN RED CEDAR IN BRITISH COLUMBIA

Abstract

Investigations of decay in Thuja plicata D. Don. in British Columbia have shown that the major heart-rotting fungi of living western red cedar on the Coast, in decreasing order of importance, are Poria asiatica (Pilát) Overh. (brown cubical pocket and butt rot), Poria albipellucida Baxter (white ring rot), Fomes Pini (Thore) Lloyd (white pitted trunk rot), Merulius sp. (brown crumbly butt rot), and Poria subacida (Peck) Sacc. (spongy white rot). In the Interior of the Province they are Poria asiatica, P. Weirii Murr. (yellow ring rot), Fomes Pini, Polyporus balsameus Peck (brown cubical butt rot), Merulius sp., and Poria subacida. Other fungi attacking the heartwood of living trees less extensively are Fomes annosus (Fr.) Cke., F. nigrolimitatus (Romell) Egel., F. pinicola (Sw.) Cke., Armillaria mellea (Fr.) Quél., Omphalia campanella (Fr.) Quél., Polyporus Schweinitzii Fr., and Coniophora cerebella Pers.On the areas investigated, loss through decay in stands 50 to 450 years of age never exceeded growth increment. It was indicated that decay in younger stands was of importance. Loss through decay and incidence of infection was appreciably higher in the Interior than on the Coast. No reliable external indications of decay in the standing tree were found.Deterioration in felled trees was caused by Poria Weirii, P. albipellucida, P. subacida, Armillaria mellea, Omphalia campanella, Fomes annosus, F. nigrolimitatus, and F. pinicola. Polyporus cuneatus (Murr.) Overh., and Hymenochaete tabacina (Sow.) Lév. were the major decay organisms of cedar sapwood and slash. Polyporus abietinus (Dicks.) Fr., P. versicolor (L.) Fr., P. semipileatus Peck, P. hirsutus (Wulf.) Fr., and Poria isabellina (Fr.) Overh. were restricted in distribution or of irregular occurrence.To assist in the identification of cultures all the major heart-rotting organisms were grown on tannic and gallic acid media. Seventy-seven species of Basidiomycetes were collected on living and dead Thuja plicata in British Columbia from 1943 to 1945.