Canadian Forest Service Publications
Addressing Marketplace Durability Issues with Post-Mountain Pine Beetle Lodgepole Pine - A Compilation of Three Reports. 2005. Byrne, T.; Uzunovic, A. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Mountain Pine Beetle Initiative Working Paper 2005-25. 46 p.
Issued by: Pacific Forestry Centre
Catalog ID: 25905
Availability: PDF (download)
This is a compilation of three reports addressing marketplace durability issues with products made from post mountain pine beetle (MPB) lodgepole pine. The first report covers the establishment of the field tests. The second report reviews the nature of bluestain, and differences between stain, mold and decay. A third report is a more general fact sheet suitable for customers or users of spruce-pine-fir lumber containing bluestained pine. The information in this compilation will enable producers and marketers of spruce-pine-fir to address perceptions they encounter in the marketplace.
Lodgepole pine lumber from trees that have been attacked by the MPB displays bluestained sapwood, which has been found to have much higher permeability than non-stained sapwood. Two long-term field tests were established to determine whether the higher permeability would affect the decay resistance of the wood. First, an "L-joint" test, based on the American Wood Preservers' E-9 Standard test method was established with 10 replicate mortice and tenon joints made of bluestained lodgepole pine sapwood, and 10 replicates made of non-stained lodgepole pine sapwood. The second test, a "sandwich" test, consists of 10 replicate, three-piece sandwich units prepared from bluestained lodgepole pine sapwood, non-stained lodgepole pine sapwood, lodgepole pine heartwood from bluestained lumber, lodgepole pine heartwood from non-stained lumber, and non-stained Scots pine sapwood. Six and one half months after installation, the Scots pine sandwich units were showing signs of deterioration due to white rot. Only a slight trace of wood-decaying fungus was noted on one bluestained lodgepole pine sample, the others were free of visible signs of decay.
In scientific literature, clear distinctions are made between the types of fungi that colonize wood, starting with the staining fungi and molds which do not cause structural deterioration of wood substance, and ending with various wood-decaying fungi that can cause severe structural damage to the wood. The bluestain fungi associated with the MPB are primary colonizers of fresh wood, causing discoloration but not deterioration. Although they are sometimes mistaken for other wood colonizing fungi, they differ biologically and morphologically from molds and black yeasts that also discolor wood, and from soft-rotting fungi and decay fungi that destroy wood. They also differ from tropical bluestain fungi that can cause strength loss.