Durability of a changing western redcedar resource

The heartwood of western redcedar (Thuja plicata) is known for its natural resistance to fungal attack, but some users of western redcedar utility pol es have suggested that its durability may be diminished as suppliers begin to harvest trees from younger stands. The decay resistance of western redce dar samples from the Pacific Northwest and Idaho was tested by using Postia placenta in a soil block test. Weight losses varied widely among and betwe en sites and were not correlated with position in the heartwood cross secti on, tree age, or silvicultural factors. With results similar to those from a 1957 study, we can infer that the durability of the currently used younge r material has not changed from that of earlier, older stocks.