甘肃小陇山白皮松生长模型研究

摘要

通过研究白皮松生长规律,探讨其生长指标的模型估算,旨在为白皮松的科学经营管理和生态效益评价提供参考.在甘肃小陇山白皮松林内设置4个标准地,采集21株解析木获得白皮松林木生长数据,建立胸径、树高和材积生长模型,并对其生长进行分析研究.比较4种常用的经验和理论函数,建立白皮松生长的最优模型,胸径的最优生长模型为三次曲线函数:D=-2.469+0.252×T+0.015 4×T2+(-1.38×104)×T3(R2=0.98);树高和材积为幂函数:H=0.122×T1.251 (R2=0.95)和V=(5.438 3×10-9)×T4.6961 (R2=0.94).白皮松胸径和树高生长呈“慢-快-慢’的生长过程.胸径平均生长量在1～40 a快速增加,在40 a后增长趋于缓慢;树高平均生长量在1～35a呈增长趋势,35 a后随着年龄的增加缓慢下降;1～20a材积总生长量增长较缓慢,21a开始材积总生长量增长迅速,60 a时达到0.620 m3,材积平均生长量和连年生长量始终保持增长,未达到最大值,还有一定的生长空间.划分白皮松的生长过程为:幼龄林阶段(1～15 a);中龄林阶段(16～58 a);近熟林阶段(＞58 a).白皮松胸径、树高和材积最优生长模型均通过检验,可为白皮松树木的生长进行较为精确的估算和预测,也为不同生长阶段白皮松的科学经营提供依据和数据支撑.%The traditional method using forest inventory data to evaluate biomass plays important roles in assessing forest biomass,verifying the remote-sensing based models and improving its prediction precision at regional scale.The growth regularity and estimation method of Pinus bungeana could provide evidence for its scientific management and ecological benefit evaluation.This study was designedin Pinus bungeana secondary forest in Xiaolongshan of Gansu province.Four sample plots were set within the stand and 21 sample trees were selected to obtain their growth data.The growth model was then established and analyzed based on DBH (diameter at breast height),tree height and volume.On the basis of previous empirical models,four commonly used models were adopted to establish the optimal growth model on the main growth of Pinus bungeana,which the optimum growth model of DBH was cubic curve function:D =-2.469 + 0.252× T+ 0.015 4 × T2 +(-1.38× 10-4) × T3 (R2=0.98),and the optimum growth model of tree height and volume was power function:H =0.122 × T1.251(R2=0.95) and V =(5.438 3 × 10-9) × T4.696 1 (R2 =0.94).The growth of DBH and tree height showed an "S"-shaped growth process of "slow-fast-slow".The average growth of DBH showed a rapid increase from 1a to 40 a,and then tended to slow down.The average annual growth of tree height tended to increase during 1-35 a,and then gradually decreased with the age growing.The total volume increment increased very slowly during 1-20 a,but began to grow fast from 21 a.The total volume reached to 0.620 m3 at 60 a and kept growing in volume average increment and current annual increment,which showed some certain growth space in next several years.In summary,the growth process of Pinus bungeana can be divided into the following stages:young forest stage (1-15 a),middle age forest (16-58 a) and near mature forest stage (＞ 58 a),respectively.The optimal models of tree DBH,tree height and volume were all passed validation,which can not only make accurate estimation and prediction for the growth of Pinus bungeana,but also provide scientific management and data support for Pinus bungeana in different stages.