Abstract
Abstract of Sustainable management of important plantations (3/3):
1.Growth dynamics on indivicual trees in Taiwania plantations (3/3):
Bella, Staeber, Hegi and tree crown volume formulas were used to calculate the corresponding competition index through three different search radius to search for the competitors for each subject tree. These indexes can be used to reflect the competition stress status for each tree in the stand. Based on the increment data obtained from each tree, evaluation on the effects of incorporating competition index was assessed. The correlation test showed the consistency between growth and competition index. The preliminary results indicated the reduction of MSE by introducing the competition index in the growth regressions. The bigger in search radius used, the larger in MSE reduction.
2.The establishment and evaluation of criteria and indicators for the sustainable forest management of Liouguei region (3/3):
The development of the framework for criteria and indicators can provide the basis used in management and science, And it is also the concrete action for practicing the sustainable forest management (SFM). The study was proposed to establish the criteria and indicators of ecosystem management for Liouquei Experimental Forest at the level of forest management unit (FMU).
In order to solve the situation of indefiniteness and uneasy to quantify, the method “fuzzy multicriteria decision making, Fuzzy MCDM) was used for analysis, the results are as follows:
The study calculate the grade of membership and membership function value between 48 indicators and 12 important degrees. The fuzzy synthetic decision was applied to evaluate the priority of indicators: the first three are「richness and diversity of species」、「area and percentage of forest types and ages」 and 「stream volume」separately. The last three are 「forest concession」、「interaction frequency between units」 and 「forest labor analysis」. At last, the sensitivity analysis was used to evaluated the weight change of indicators.
3.The management strategies on natural regenerated broad-leaved trees in Taiwania plantations (3/3):
3 study sites (50×50㎡) will be chosen in Taimali Research Center TFRI to investigate the composition and structure of the Taiwania plantations and undreground regenerated broadleaved seedling. Simultaneously, nearby natural forest will be investigated to analyze the similarity between natural forest and the undreground natural regenerated vegetations in Taiwania plantations. Beside, this study will estimate different approaches of multisilviculture system based on the concept of forest restoration ecology and aplly to current and further foest management strategies.
4.Study of restoration after typhoon disturbances on Liukuei plantations (3/3):
he management purpose of plantation is to produce woods with high economical values. Selecting suitable planting species and operational strategy are necessary. The materials of this study are Taiwania cryptomerioides and Cunninghamia konishii plantations, serious destroyed by typhoon and distributed in Liouguei Research Center, Taiwan Forestry Research Institute. We set up 7 transect lines; each is composed of 30-50 meters long. All woody plants in the area 1 meter astride transect lines, species with dbh ≥ 1cm present in the quadrates were identified and their dbh were measured. Light environment under the forest canopy above each transect line were estimated by 100 hemispherical images to measure the average light transitivity of each microhabitats. We planted Zelkova serrata, Michelia compressa and Machilus thunbergii seedlings, high economical value and primitive tree species, in three different microhabitats: (1) closing canopy with nature regeneration trees in the substratum with relative luminosity under 20% (2) spare canopy trees with nature regeneration trees in the substratum with relative luminosity between 40% and 60%(3) spare canopy trees without nature regeneration trees in the substratum with relative luminosity above 70%. The objective of this study is to explore the survival rate and growth status of seedlings of three different tree species under different relative luminosity. The results are expected to apply to operational technique of plantations.