In BC alone, about 3,600 MMfbm of export lumber is chemically treated each year to prevent discolouration due to sapstain, mould, and decay. In a survey of fungal stain in Canadian softwood sawlogs, some mills indicated a considerable loss in potential revenue due to fungal stain. A better understanding of the mechanisms of infection of sawn softwoods is required in order to develop and propose appropiate means of protection and prevent the development of these fungi. The study will identify the major wood degrading fungi occuring in Eastern Canada and some of the critical factors contributing to fungal degradation. These factors will then be used to devise integrated control programs wich take into account harvesting and storage of timber, protective treatment and lumber delivery.
A total of 4 mills have been visited in Eastern Canada, representing three provinces and different geographic regions. For each mill visited, a questionnaire on wood sapstain was completed with the mill personnel to identify the critical factors for fungal growth. Results of the questionnaire indicate that the storage time (forest and lumber yard) of unseasoned logs and lumber is the most critical factor in the development of sapstaining fungi. The problem is more frequent in warm and humid seasons, between May and September. At the moment, the problem is more or less controlled by stock rotation in a first in first out basis.
Collection of wood samples fom logs and lumber was performed at each mill in order to identify the major wood degrading fungi occurring in Eastern Canada. Fungal isolation, purification and identification from wood samples (logs and lumber) as begun in the laboratory and up to now eleven fungal species have been identified from stained jack pine lumber in one mill, five of wich were sapstaining fungi, four moulds and two decay fungi.