林业科技工作者常常需要了解林木径向生长量。过去野外观测中常用的测径轮尺,精确度只能达到0.5cm。现在用的围尺对林木短期径向生长也很难精确测定。国外具有一种电测仪器,固定在树上,能随时记录直径生长量,但在使用中保管维护很麻烦,不易在我国现有条件下推广使用。我们于1988年设计试制了“树干径向生长测微仪”(见图1),经过两个生长季的观测使用,效果很好,而且精度达到1/100～5/100mm,能测出林木1—2天的径向生长 Forestry scientists often need to understand the radial growth of trees. In the past, the commonly used diameter measuring caliper in field observation can only reach 0.5cm. It is also difficult to accurately measure the short-term radial growth of trees nowadays. Abroad with a kind of electrical measuring instruments, fixed in the tree, can record diameter growth at any time, but in custody of maintenance is very troublesome, not easy to promote the use of existing conditions in our country. We designed and tested “Trunk Radial Growth Micrometer” in 1988 (see Figure 1). After two growing seasons, we observed that it worked very well and the accuracy was 1/100 ~ 5 / 100mm. 1-2 days of radial growth