. Deterioration of sugar maple following logging damage. Trees Wounds and injuries; Wood-decaying fungi; Sugar maple. Figure 9.—Decay traced to large scars on two 12-inch sugar maples. The even- tual destruction•of severely scarred merchantable trees is inevitable. Upper Photo: Decay at 20-year-old scar. Lower Photo: Rot caused by Daedalea unicolor at a 10- year-old scar . Although the use of tree-risk classes will undoubtedly be helpful for the cruiser or tim- ber marker in estimating trunk defects, the sawmill operator is concerned primarily with the volume and grade yield of lum- ber from t
. Deterioration of sugar maple following logging damage. Trees Wounds and injuries; Wood-decaying fungi; Sugar maple. Figure 9.—Decay traced to large scars on two 12-inch sugar maples. The even- tual destruction•of severely scarred merchantable trees is inevitable. Upper Photo: Decay at 20-year-old scar. Lower Photo: Rot caused by Daedalea unicolor at a 10- year-old scar . Although the use of tree-risk classes will undoubtedly be helpful for the cruiser or tim- ber marker in estimating trunk defects, the sawmill operator is concerned primarily with the volume and grade yield of lum- ber from the logs processed. It was established that rot at logging scars in maple pro- gresses rapidly longitudinally but slowly towards the core of the log. Decay in some logs with 10-year-old scars was of- ten "sawed off with the slab" or removed by the edger. No losses from decay resulted in these instances even though wood-destroying fungi were es- tablished at the logging scar. It is possible that certain decay fungi become established during the same season that wounds occur but for several years do not meet with favorable conditions that permit measurable amounts of rot to develop. For example, Polyporus versicolor was isolated from a 6-inch-wide log- ging scar, but this fungus caused no appreciable defect in 10 years. Since it progressed only 2 inches in depth, most of the rot area was removed the slab when the log was dissected into lumber . Although the head sawyer may occasionally avoid decay at scars in some logs, it was demonstrated that logging scars (especially 20-year-old wounds) commonly reduce both log scale and log grade. Reduction in scale occurs when logging scar defects are "scaled-out" or deducted from the gross board-foot volume or when sections of trees are culled in the woods as a result of excessive defect (more than 50 percent of the gross log scale in cull). Loss in log quality occurs when sur- face defects such as logging scars
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Keywords: ., bookcentury1900, booksubjecttreesw, booksubjectwooddecayingfungi
