天山云杉立地指数时空估测中的变异函数模型优化研究

Forest site is the foundation of forest productivity, so it is of great theoretical and practical significance for the ecosystem health , quality and efficiency of forest, to evaluate the quality of forest site scientifically and reasonably.In this research project, for the scale problems in the process of spatial and temporal variability of site index when carry out the spatio-temporal evaluation of forest site index, the spruce forests located at the middle of Tianshan mountain were token as the research objects, aiming at explore the optimization methods of forest site index variagram, the following three researches were developed, basing on geostatistics and GIS-based spatial and temporal analysis theory and techniques.First, to ensure the selection of forest site index variagram qualitatively and quantificationally, the optimum selection of model of forest site index variagram were studied; second, the multi-scale box-model of forest site index variagram were also researched, by which the anisotropy and multi-scale dependence of forest site index were described effectively; in addition, the spatio-temporal extended model of forest site index variagram were also studied, because of reflecting the spatio-temporal process and differentiation of forest site index based on the above model.This research project aimed at improving the accuracy and reliability of the spatio-temporal estimation of forest site index effectively, achieving the fusion of static simulation and dynamic spatio-temporal estimation, as well as revealing the spatial and temporal variability law, and providing the scientific basis for spatio-temporal estimations, simulations and evaluations of quality and productivity of forest site.

森林立地是森林生产力的基础，科学合理地进行立地质量评价，对森林生态系统健康、质量和效益具有重大理论与实践意义。本课题针对森林立地指数时空估测中立地指数时空变异过程中的尺度问题，基于地统计学和GIS时空分析理论与技术，以天山中部的天山云杉林为实验对象，探索森林立地指数变异函数优化方法，开展以下3项研究：（1）立地指数变异函数模型优选方法，确保变异函数的定性化与定量化选择；（2）立地指数变异函数多尺度套盒模型，有效刻画立地指数各向异性和多尺度依赖性；（3）立地指数变异函数时空扩展模型研究，有效反应立地指数的时空过程与分异。旨在有效提高立地指数时空估测的精度与可靠性，实现静态模型模拟与动态时空估测的融合，为揭示新疆天山云杉立地条件的时空变异规律，开展森林立地质量和生产力的时空估测、模拟与评价提供科学依据。

天山云杉立地指数时空估测中的变异函数模型优化方法，有助于实现森林立地指数静态模型模拟与动态时空估测的有效融合，对森林立地质量和生产力进行高精度和高可靠性的时空估测与评价具有理论和实践意义。本研究基于实测的天山云杉立地指数数据，利用地统计理论从天山云杉立地指数最优变异函数模型拟合、立地指数时空变异函数模型表达形式等方面对天山云杉立地指数进行了研究分析。研究结果有：天山中部天山云杉立地指数最佳变异函数理论模型选择球形模型、空间上不存在明显的各向异性并且具有中等空间相关性；通过整合时序分析、机器学习算法基于时空随机过程构建了天山云杉立地指数时空变异函数模型表达形式，从理论上提升时空估测精度和可靠性；为便于理论成果的实际行业应用和研究成果展示设计开发了天山云杉立地指数和空间格局评估两个系统。研究成果揭示新疆天山云杉立地条件的时空变异规律，为森林立地质量科学决策提供了强有力的理论方法和工具。