Improvement and Compilation of Density Management Diagram of Larix principis-rupprechtii Mayr Forest in Northern Hebei

摘要

Stand density management diagram is an average stand model that indicates forest growth at differentstages, providing a scientific basis for the mastery of stand density, the prediction of forest growth,the control of water conservation and the measurement of carbon storage. Larch forests in northernChina, that is faced with such environmental problems as sand storm and smog, serve the functionsof wind break and sand fixation as well as water conservation. This paper makes some improvementto the density management diagram by adding a crown width line to obtain appropriate stand density.In this research: 1. A stand density management diagram is constructed to show growth informationin Saihanba Forestry, Hebei province, into which contour lines of constant tree height, degree ofcloseness, natural thinning, diameter at breast height and crown width are included. 2. The plantingdensity should be set at 3,000 plants.hm-2 and 300 m3 timbers are expected to be obtained from harvestcuttings. Two harvest cuttings should be arranged between 16 and 29 years, with cutting intensitiesof 28.4% and 36.4%, respectively. The density management diagram is to be constructed to predict thegrowth of Larch forests in northern China, so as to provide reference for the making of forestmanagement plans and the reasonable arrangement of stand density.