Study On The Natural Uneven-aged Forest Resource Assets Evaluation

Natural forests are the main part of the forest resource in our country. Natural forests play an irreplaceable role in protecting the national ecological safety, maintaining the ecological balance, improving the quality of the environment and protecting the biological diversity. Meanwhile, Natural forests also play a most important part in production of forest products. Natural forests are an important material foundation to achieve social and economic sustainable development.Since the implementation of Natural Forest Protection Project in 1998, Natural forests'protection has been strengthened, and the non-natural forest protection project regions in the South are also enforced to use selective cutting to operate the natural broad-leaved forests. The proportion of the national uneven-aged forests will increase under all these indemnificatory operation rules and measurements. Meanwhile, it is a new challenge for the operation management to uneven-aged forests. Our country promoted to reform the collective forest rights system in 2008. With the construction of forest land and forest circulation system, the foundation of property rights trading platform, and the same usage of the forest land, the phenomenon which the owners of the forest land subcontract, rent, transfer, buy into, mortgage the rights and ownerships of their own forest land according to law will apparently increase. Therefore , the asset valuation business of natural uneven-aged forest will increase and the requirement for accuracy of valuation will improve. The importance of the valuation of uneven-aged forest will become increasingly important. However, at present, uneven-aged forest evaluation has a weak study. In the current system of property valuation, there exist the misuse of evaluating methods between even-aged forest and uneven-aged forest. This paper based on the problems existed in the process of uneven-aged forest evaluation, incomplete verification methods and distempered parameters and indexes and so on, and also based on the study of sample plots to come to some suggestions to improve the property valuation method of natural uneven-aged Forest.(1) According to the related changes of two factors, annual average growth rate and volume per unit area of the study plots, the linear models were simulated, including power model and index model for growth rate-growing stock pattern by EXCEL software, and the index model y =17.568e-0.0065x was selected for its correlation coefficient was the largest in three models.(2) In the process of property valuation, the selective cutting period of regular natural uneven-aged forest was calculated according to the related laws of selective-cutting intensity and invariant average growth rate per year, but it ignored the fact that the level of forest cumulating and the annual growth rate were changing continuously, and the growth of natural uneven-aged forest was a complicated changing process. So its quantitative change was impossibly even every year. Thus, it was unreasonable to settle the selective-cutting period with a certain invariant growth rate of natural uneven-aged forest. Making use of the mathematics patterns to calculate the changing annual growth rate which was so-called dynamic growth rate under the different cumulating level in the post selective-cutting phase and the recovery phase could well show the length of time which natural uneven-aged forest need to recover to the original level after selective-cutting. Therefore, to settle the selective cutting period through the dynamic growth rate and choose appropriate selective-cutting intensity, then, we could deduce a dynamic growth pattern:Mn expressed the forest quantity cumulating per hectare in the year "n" after selective-cutting. When Mn≥M, that is, when the forest quantity cumulating per hectare recovered to original level, the selective cutting period calculated with the dynamic growth rate U=n. This growth rate-growing stock pattern made up the shortage of calculating the cutting period with the certain invariant growth rate, improving the method of settling the selective cutting period.(3) The calculated dynamic growth rate could really show the value of this forest. This paper, basing on this result calculated with the dynamic growth rate to analyze five different evaluations calculated with the fixed growth rate, tried to find out a fixed growth rate from five different fixed growth rates that can replace the dynamic growth rate, and then processed the evaluation and adjusted the coefficient with this growth rate. This work not only can make the result nearly equal to the valuation calculated with the dynamic growth rate, but also can easily gain the factors and calculate them. In order to well and truly evaluate the value of natural uneven-aged forests, we might use"golden section point"method to calculate growth rate to replace the dynamic growth rate,which had better applicability.(4) The diameter class distribution of natural uneven-aged forest had a big influence on the whole evaluation,so the way of investigating the uneven-aged forest resources were suggested to use angle gauge control scaling, This method not only can insure work efficiency,but also can guarantee precision. The result worked out by angle gauge control scaling could reflect the forest quality objectively. To show the forest quality exactly and guarantee the precision of surveying and calculating the average stand diameter at breast height, the starting measured diameter was suggested to be raised from 6cm to15cm for the natural uneven-aged forest.