论文部分内容阅读
为了摸清河北杨胸径生长规律,1986—1987两年来,我们在延安树木园标本区设立了观测点。观测对象为7—8年生河北杨,共20株。每年春季从4月下旬开始,每旬观测1次。观测项目有胸径生长量、新梢生长量。两年的观测发现:在当地正常气候条件下,河北杨径生长量从5月上旬开始,9月下旬停止。生长期间可划分为三个阶段:5月份为生长初期,这时多风少雨,气温高,气候干燥,土壤干旱,又适河北杨的花期,消耗大量养分,径生长缓慢;6月上旬至8月中旬为速生期,此期间气温高,降雨多,空气湿度大,径生长量约占全年生长量的80%,此期间新梢生长开始减缓,径生长量进
In order to find out the law of the growth of Hebei DBH, from 1986 to 1987 two years ago, we set up observational sites in the specimen area of Yan’an Arboretum. The observation objects are 7-8-year-old Hebei poplar, a total of 20 plants. Each spring from the beginning of April, every 10 days observation. Observed projects have diameter growth, shoot growth. Two years of observation found that under normal local weather conditions, the growth of Hebei poplar began in early May and stopped in late September. Growing period can be divided into three stages: May is the beginning of growth, when windy, rainy, high temperature, dry climate, soil drought, but also the flowering of Hebei Poplar, consume large amounts of nutrients, diameter growth slow; early June to 8 Mid-month for the fast-growing period, during the high temperature, rainfall, air humidity, diameter growth accounts for about 80% of annual growth during this period shoot growth began to slow down,