tailieunhanh - Báo cáo lâm nghiệp: "A linkage among whole-stand model, individual-tree model and diameter-distribution model"

Tham khảo luận văn - đề án 'báo cáo lâm nghiệp: "a linkage among whole-stand model, individual-tree model and diameter-distribution model"', luận văn - báo cáo phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | JOURNAL OF FOREST SCIENCE 56 2010 12 600-608 A linkage among whole-stand model individual-tree model and diameter-distribution model X. Zhang Y. Lei Research Institute of Forest Resource Information Techniques Chinese Academy of Forestry Beijing China ABSTRACT Stand growth and yield models include whole-stand models individual-tree models and diameter-distribution models. In this study the three models were linked by forecast combination and parameter recovery methods one after another. Individual-tree models combine with whole-stand models through forecast combination. Forecast combination method combines information from different models disperses errors generated from different models and then improves forecast accuracy. And then the forecast combination model was linked to diameter-distribution models via parameter recovery methods. During the moment estimation two methods were used arithmetic mean diameter and quadratic mean diameter method A-Q method and arithmetic mean diameter and diameter variance method A-V method . Results showed that the forecast combination for predicting stand variables outperformed over the stand-level and tree-level models respectively A-V method was superior to A-Q method on estimating Weibull parameters these three different models could be linked very well via forecast combination and parameter recovery. Keywords forecast combination linkage parameter recovery stand growth and yield model In forest management forest growth and yield models play a very important role in studying forest growth processes and predicting forest growth. Forest growth and yield models can be classified into three broad categories whole-stand models individual-tree models and diameter-distribution models Munro 1974 . Whole-stand models are models that use the stand as a modelling unit Curtis et al. 1981 Li et al. 1988 Tang et al. 1993 Wei 2006 whereas individual-tree models take the individual tree as a studied object Zhang et al. 1997 Cao 2000 Cao et .