| The models of existing forest stand management (MFSM) in Xiaolongshan, Gansu Province were summarized based on the stand structure and production evaluation in this study, Totally 11 kinds of MFSM under 3 forest management technical systems were selected for study and a zonal climax community—Quercus aliena var. acutiserrata near primary forest was defined as the reference forest stand. There are 9 kinds of MFSM under the secondary forest comprehensive silvicuture technical system, the model of stand structure optimization adjustment under the forest management based on stand structure optimization technical system, and the model of target trees cultivation under the close to natural forest management technical system in all of the MFSM. The differences of state characteristics between MFSM stands and reference stand were analyzed by means of the genetic distance analysis and relative difference ratio based on improved indicators, and the method of effectiveness evaluation on management models was proposed including technical rationality and economic feasibility. The suggestions how to improve forest management technology system of secondary forest and management models of typical stands in Xiaolongshan forest area were proposed according to the results of effectiveness evaluation of the 11 kinds of forest management models. The main conclusions were as follows:(1) The effective evaluation method of stand management models was established. The characteristics of MFSM stand were described using improved indicators. The difference of structure state features with distribution and non-distribution was quantitatively analyzed using the genetic distance method and relative difference ratio respectively. The technical rationality of MFSM was measured by the extent of the management stand close to natural stand (reference forest stand) in unit labor; the economic feasibility of management models was measured by timber quantity obtained in unit labor; the effectiveness was synthetically evaluated based on its technical rationality and economic feasibility.(2) The result of difference analyzing between 11 kinds of MFSM stands and reference forest stand was presented in the study. The state features of natural type of MFSM stands were closer to the zonal climax community than the plantation stand of transformation-regeneration type. In the type of natural forest MFSM, the difference of state characteristics from reference stand was the smallest for the model of clear cutting of natural forest-replanted Pinus tabulaeformis -natural restoration (Model 1),the model of target trees cultivation (Model 4) was the largest. However, in the type of transformation—artificial regeneration MFSM, the differences of the model of overall transformation of shrubbery artificial regenerated by Pinus armandii—no tending (Model 8) were the smallest compared with the reference stand, whereas the model of overall transformation of shrubbery—artificial regenerated by Larix kaempferi—tending (Model 11) was the largest.(3) The results of difference analysis using different indicators showed that the difference of forest stand composition and space utilization was not significant between the stand type of natural forest MFSM and the reference stand, but the difference between the stands of transformation—artificial regenerated and the reference stand was significant. The terms of stand composition showed the difference between Model 1 and the reference stand was the smallest, whereas the difference between the overall transformation of shrubbery—artificial regenerated by P. tabulaeformis—tending (Model 10) and the reference was the largest. In term of space utilization, the difference of optimization adjustment of natural forest stand structure (Model 3) was the smallest compared with the reference stand, but the Model 11 was the largest. In term of species diversity, the difference of Model 5 was the smallest compared with the reference stand, but the Model 11 was the largest. .In term of vigor, the difference of Model 1 was the smallest compared with the reference stand, but the belt transformation of shrubbery—artificial regenerated by P. armandii—no tending (Model 7) was the largest difference.(4) The analysis of the technical rationality of MFSM showed Model 3 was best followed by Model 4, both of which were significantly better than all models of secondary forest comprehensive cultivation. In type of secondary forest comprehensive cultivation, the selective cutting of natural forest (Model 2) was the best one on technical rationality, whereas the Model 10 was the lowest one. The evaluation results of the technical rationality reflected not only the economical cost of MFSM, but also the level of realization of MFSM goal.(5) The economic feasibility of the Model 4 was the highest and was similar to the Model 3, but all models of comprehensive cultivation were lower. In models of secondary forest comprehensive cultivation, the economic feasibility of natural regeneration type was higher than shrubbery overall transformation-artificial regeneration type, and the belt transformation of shrubbery—artificial regeneration type was lower because of without timber production. The main economical cost of MFSM in XLS was labor, which conformed to the actual situation in XLS forest area that the economic feasibility of management models measured by timber quantity which was obtained in unit labor.(6) The effectiveness of MFSM was comprehensively evaluated based on its technical rationality and economic feasibility. The Model 3 was the most effective, and Model 4 was the second, both of which were more effective than all models of secondary forest comprehensive cultivation system .The effectiveness value of Model 3 was 8.334, and Model 4 was 7.047, respectively, the value of other models≤4.333.In 9 of the secondary forest comprehensive cultivation, the model of natural forest management was more effective than that of transformation—artificial regeneration. Among models of natural forest management, the Model 2 was better, whereas the Model 1 was worse. However, in the type of transformation—artificial regeneration, the effectiveness of transformation of natural forest was higher than the belt transformation of shrubbery and the models of overall transformation of shrubbery were the lowest. Among these, the model of belt transformation of shrubbery—artificial regeneratedby P. Tabulaeformis- not tending (Model 8) were the best, and the Model 11 was the worst.(7) The technical systems about how to improve the secondary forest comprehensive cultivation in XLS forest area was discussed, a suggestion to improve existing forest management models was made, and 7 kind of demonstrate models were presented in this study.The difference analysis method, which was used to evaluate technical rationality of forest management models with the zonal climax community as reference system enriched the content of stand difference comparison, and the effectiveness evaluation method of forest management models based on the technical rationality and economic feasibility could be a new choice to evaluate the forest management model. |
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