摘要:
3-PG模型是一个应用气候、立地条件、经营措施和树木生理特性来模拟森林生长的机理模型,在国外被广泛应用于森林经营.为了准确、快速预测速生尾叶桉人工林生产力,该文运用3-PG模型对我国广东省雷州半岛上广泛种植的尾叶桉的生长规律进行研究.用纪家林场尾叶桉标准地4年的观测数据来校正模型参数,用河头林场尾叶桉生长数据来验证模型在新立地条件下的性能.模型校正结果中,林分材积、树高和胸径的模拟平均精度都超过92%,相关系数超过0.93;除树根外林分生物量和叶面积指数的模拟精度都超过83%;观测的树根生物量比模型值偏低40%,主要原因是树根系统非常庞大复杂,远远超出了我们所能挖掘的深度,因此测定粗根和细根的生物量都会偏低.模型验证结果中,林分材积、树高和胸径的平均模拟精度都超过94%,相关系数达到0.98以上.研究结果表明:3-PG模型是预测桉树人工林生产力的一种有效工具,一旦模型被参数化便可应用于不同地区,而且其模拟精度和可靠性是令人满意的.
Abstract:
The 3-PG process-based forest growth model is increasingly widely used for both research and management of various forests in a number of countries in relation to climate,soil conditions,forest management and species.In order to reliably and rapidly predict plantation production of fast-growing Eucalyptus urophylla,the 3-PG model was applied to study the growth laws in the stands of E.urophylla on the Leizhou Peninsula of Guangdong Province.The model was calibrated on the basis of 4-year monitoring data at Jijia Forest Farm and was tested using growth data at Hetou Forest Farm.The calibration results for various stand variables were very satisfactory(overall mean r2 > 0.93 and mean accuracy > 92% for stand growth;accuracy > 83% for stand biomass and LAI) except that root biomass was overestimated about 40%.In both cases of fine and coarse root measurements,root biomass may be underestimated because root system actually extended to greater depth than that can be assessed.In the test,all the mean accuracies were > 94%,with r2 > 0.98.The results demonstrated that the 3-PG model was a convenient and efficient means of predicting the productivity of E.urophylla plantations,and can be used to predict the performance of that species and its response to conditions in new areas with the satisfactory accuracy and reliability when parameterized for a particular species.Therefore,it has considerable potential value as a research tool and practical means of providing a sound and credible basis on sustainable E.urophylla plantations for forest managers.
百度学术
下载:
