Sour-felling, or delayed delimbing after harvesting, has long been proposed as a method to accelerate drying of the tree stem, in order to reduce handling and transportation costs and reduce energy consumption and drying degrade in kiln drying. Recently it has also shown promise as a method to reduce development of bluestain in harvested trees. In Forintek discussions with several large sawmills in Alberta, bluestain was estimated to cause losses of at least $30 million (CAN) in a summer when weather conditions resulted in heavy stain development. Previous Forintek trials were conducted in Alberta to assess stain development in sour-felled and control trees, but these studies did not examine other possible effects of sour-felling on the manufacture of wood products, such as development of checks, ease of debarking and milling, or other unforeseen factors.
Unfortunately, weather conditions during the storage period of this test were not conducive to bluestain development, and there was no observed difference in bluestain on lumber produced from sour-felled or control logs. Therefore, other than moisture content determination of lumber, further assessment of product quality was not undertaken. There was little difference in average moisture content of lumber produced from control and sour-felled logs, although sour-felled logs yielded slightly wetter lumber. An observed advantage of sour-felling was substantially less fibre loss from sour-felled logs than from control logs during debarking.