辽宁省章古台樟子松固沙林提早衰弱的原因与防治措施

REPORT ON THE CAUSES OF THE EARLY DECLINE OF PINUS SLYVESTRIS VAR.MONGOLICA SHELTERBELT AND ITS PREVENTATIVE AND CONTROL MEASURES IN ZHANG GUTAI OF LIAONING PROVINCE

樟子松 (Pinussylvestrisvar.mongolica)从内蒙古呼伦贝尔地区红花尔基沙地引种到章古台 ,在中幼龄林阶段一直表现稳定 ,生长较快。但是 ,至 35～ 4 0年生以后出现提早衰弱、生育周期缩短等问题。通过对1 7年定位观测资料的分析表明 ,章古台樟子松固沙林提早衰弱的原因主要是由于引种地区纬度跨越大 ,水分、热量比原分布区充足 ,引起了樟子松自身生长规律的变化 ,高峰生长期提前、峰值高、峰期短 ,旺盛生长期缩短等。另外 ,由于当地 5、6月份降水量少 ,在干旱年使林分出现水分亏缺 ;7、8月份降水集中 ,又造成林分高温高湿的环境条件 ,在这种水热条件作用下 ,当林分生长势降低时 ,便感染枯梢病。由于干旱和枯梢病的影响 ,林分进一步提早衰弱。但是 ,樟子松仍然是当地的主要造林树种 ,在固沙造林中还没有其他树种的生态效益和经济效益能够超过樟子松。选育抗病型良种 ,营造混交林 ,实行集约化经营等措施可以降低发病率 。

Pinus slyvestris var. mongolica was introduced to Zhang Gutai from Honghuaerji Sandy Lands, Hulunbeier of Inner Mongolia. During its young and middle ages, the growing was stable and fast. However, to those 35～40 years old trees, early decline occurred , growing period shortening resulted. By observation on 17 fixed positions, analysis showed that the early decline was mainly caused by the changes of its growing pattern, such as the peak growth period shifted to an early date and became shorter; peak numerical value was high and the vigorous growing period became shorter. due to moisture and heat differences between its original and present growing places. Moreover, another reason of early decline was the development of Diplodia, which was caused by the local climate, that is less precipitation in May and June and concentrating precipitation in July and August. However, Pinus slyvestris var. mongolica is the main species in afforestation which is superior in ecological and economic benefits to others, therefore, in order to reduce the development of diseases and prolong the growth period, selection of decease resistant species, establishment of mixed plantation with intensive management are adopted as the main measures to solve the problem of early decline.