Application of Ecosystem Management Decision Support System in selecting suitable site for Taiwania
Taiwania is distributed between 1000~2000km in elevation in the Luikuei Experimental Forest, but grows better between 1200~1700km. According to the forest type inventory in the study area, the planting sites with better quality are listed as Table 1. It shows that the suitable slope for Taiwania is from 15 degree to 45 degree, but must be constrained under 35 degree when considering the working sites permissible. As for the aspect, though some references show Taiwania was distributed in South, the sunlight was compensated in this study area, because it's nearby tropical. Because Taiwania can be found in all the aspects, so the aspect factor was abandoned in this study.
Table 1. Distribution of Taiwania in the study area.
| Forest
compartment | Plantation
area (ha.) | Elevation
(m) | Aspect | Slope
(degree) |
| 2 | 38.5 | 1500-1600
| North-West | 20-40 |
| 2 | 40 | 1500-1600 | North-West | 20-40 |
| 2 | 12.9 | 1000 | North-West | 20-40 |
| 3 | 58 | 1500-1600 | South-West | 20-30 |
| 3 | 20 | 1500
| South-East | 20-35 |
| 3 | 61.3 | 1300-1500
| South-West | 20-35 |
| 3 | 26.5 | 1400
| South-West | 20-35 |
| 10 | 24 | 1400
| South-East | 20-30 |
| 12 | 24.8 | 1450
| South-East | 20-30 |
| 12 | 25 | 1500
| South-East | 20-30 |
| 12 | 23.7 | 1300
| South-East | 20-30 |
| 12 | 18.5 | 1500
| North-East | 15-25 |
| 12 | 19.2 | 1500
| North-West | 15-30 |
| 12 | 15 | 1300
| North-West | 15-30 |
| 13 | 47.4 | 1500
| North-East | 20-40 |
| 13 | 24.1 | 1600
| North-West | 20-45 |
| 14 | 41.3 | 1500
| South-East | 25-40 |
Soil type determines soil characteristics such as texture, water drainage, and nutrient. Soil type was selected in this study, and soil inventory book was used as reference to select soil type. Soil types such as Fcs, Mls, Nsa, Nsa-Ycl, Stm, Wss, Ycl, Gts-Mls, Stm-Ycl, Wss-Ycl are with sandy-loam texture, well water drainage and suitable for planting, were selected.
3. Results
When topographic factors were considered, most of the study area were included in the result because the average values were used for first order watershed unit, and the values were too rough to determine the species (Fig. 1). Therefore, soil factors must be selected in species determination. From another perspective, the species determination is a local and small-scale forest management programming when considering scale, therefore the micro condition of habitat must be considered (soil, micro-climax…etc).
When soil factors were added to the EMDS assessment, the suitable sites were reduced and more detailed information was shown in the resulting map. (Fig.2)
The results were compared with the real Taiwania distribution (Fig.3). In the northern part of the study area, most areas of distribution match with each other quite well. It shows that it is feasible to apply EMDS in species determination. As to the southwest part of the study area, there are some Taiwania distributed in the real world but are not suitable based on EMDS analysis. Perhaps the Taiwania isn't the suitable species in the southwest part, because the growth of Taiwania there is under average. At last, the southeast part is suitable based on EMDS analysis but no distribution was found in the real world. It suggests that the manager can try to use Taiwania as the planting species in this part.
