各位英语达人帮忙咯
The quality of aspen logs (Populus tremula) was studied by sawing sample logs. For grading of aspen logs and sawn timber, the proposed system of Keinanen et al. (1995) plusthe reject-grade was used. The length of the knot-free section at the base of an aspen stem is short. Green knots are concentrated in the top logs and red knots at the top of the butt logs and first middle logs. Most of the decayed knots are located in the second middle logs and top logs.
参考答案:山杨的原木((Populus tremula)的质量被锯样品原木学习.因为山杨的等等把原木和锯木材,Keinanen的建议的系统分等级(1995)plusthe瑕疵品-级被使用.在一山杨的茎干的底座旁无结-的部分的长度短缺.绿色结在最高原木和红结中在粗大的一头原木和首次中间原木的顶部是浓缩.腐烂的结的绝大部分位于第二中间原木和最高原木.