优树选择是林木良种化的一项基本工作,其选择标准是随育种方向而定的。本文着重论述用材林的优树标准和选择优树的指数法。一、优树标准用材林的优树标准,应以木材的速生、丰产、优质为主。例如云南松优树的干形和木材纹理通直、抗性强、长势旺,是其主要的质量特征,立木材积大,是其主要的数量特征。但是,质量和数量不是彼此孤立的,云南松高生长速度愈快,树干干形愈直,木材纹理扭转率愈小。各种数量特征(胸径、树高、形数、树皮厚度、冠幅以及枝下高等)与立木材积之 Tree selection is a tree planting of a basic work, the selection criteria is based on the direction of breeding. This article focuses on the excellent tree criteria for selecting timber and the index method for selecting superior trees. First, the excellent tree standard timber forest tree criteria should be fast-growing timber, high yield, high quality-based. For example, the dry and woody texture of Pinus yunnanensis is straight, strong and vigorous. It is the main quality characteristic of the tree and its stand volume is large. It is the main quantitative feature. However, the quality and quantity are not isolated from each other, Yunnan Songgao growth faster, more straight trunk dry, wood texture twist rate smaller. The number of characteristics (DBH, tree height, number of shapes, bark thickness, crown width and branch height) and standing timber volume