According to the abundance of native broad-leaved trees species resources in Taimalii research centre, TFRI, the study focus the interests on the biology, ecology and growth characteristics of the mixed stands and plantations in this area, planning workshop including the investigation of growth status, and the monitoring on the affections of different mixed planting models to micro condition of the site. The results will be utilized to design the strategies of establishment and the accessing management of the mixed stands. On the other side, to evaluate the benefit effect of them will be analyzed simultaneously, by the way, regulation procedures will be used to analyze the effectiveness of the carbon sink of different management model of mixed stands. The research results for the third year are as follows:
On the aspects of the forest stocks, the best combination of the core and periphery species is both Formosan Michelia separately. The average stock is 183.99 m3/ha. On the other hand, the stocks values larger than the total average are for the combination of Comphor-Formosan Michelia, Comphor- Comphor and Formosan Michelia- Comphor. The values are 162.40、143.39、151.13 m3/ha separately. The lowest value of the stock is the combination of Formosan Ash- Formosan Michelia and its value is 113.24 m3/ha. On the aspects of the carbon sinks, the largest value is the combination of Formosan Ash- Formosan Ash and the average carbon sink is 85.74 ton/ha. On the other hand, the stocks values larger than the total average are for the combination of Formosan Michelia -Formosan Michelia, Formosan Ash – Comphor, Formosan Ash- Formosan Michelia and Formosan Michelia - Formosan Ash. The values are 76.39、75.03、70.52、71.59ton/ha separately. The lowest value of the carbon sink is the combination of Comphor - Comphor and its value is 47.09 ton/ha. From the above results, the values of the stock and carbon sink for the combination of Formosan Michelia- Formosan Michelia are 183.99 m3/ha and 76.39ton/ha separately. And the values of the stock and carbon sink for the combination of Formosan Ash –Formosan Ash are 131.9 m3/ha and 85.74 ton/ha separately.
On the aspects of vegetation survey, the biodiversities for different mixed models display 1% significant difference. The combination of Formosan Ash- Formosan Michelia got the largest value (0.85) and the Comphor – Comphor the smallest (0.67). For the micro-climate aspects, the related Luminosities display 1% significant difference also. The combination of Formosan Michelia - Formosan Ash got the largest value (63.34%) and the Comphor – Comphor the smallest (15.02%) also.
For the analysis of benefit-cost effect, the largest NPV is the combination of Formosan Michelia- Formosan Michelia(119,968 NT dollars/ha) and the smallest is the Comphor – Comphor combination(-70,594 NT dollars/ha). Because the high relationships between the NPV and IRR, the IRR reveals the same tendency, i.e., the combination of Formosan Michelia- Formosan Michelia shows the largest((11%), and the Comphor – Comphor the smallest (-1%).