We are on the way of developing site preparation equipment to further mechanize planting operations. As preliminary work for the development, we studied the characteristics of various site preparation methods. We prepared test site using vehicle based machines to make patched spots by mounding and scarification. We classified test plots to 4 categories, which are mound, pit from mounded spot, scarification and untreated. For each category we measured soil density, moisture content and its change, survival rate of planted containerized Hinoki (Chamaecyparis obtusa) seedlings and vegetation coverage 1 year after treatment. The results of soil density in order are scarified < untreated ≒ mound < pit, those of moisture content are pit > untreated > scarified > mound, those of survival rate are pit > scarified ≒ untreated > mound and those of vegetation coverage are scarified < pit ≒ mound ≒ untreated. In reference to soil density and plant coverage (which is more suitable when it is smaller for seedling growth), scarification was found to be most favorable for planting. However in this test the limiting factor is found to be moisture content due to dry site environment, which caused pit plots to have the highest seedling survival rate.

View full abstract

The relationship between forest improvements and road access was analyzed in Shitara and Toei, Aichi Prefecture, Japan. Public, forest, and strip roads, and five basic forest operations - planting, weeding, pruning, cleaning, and thinning - conducted by the Forest Owners' Association as subsidized projects related to reforestation and silviculture from 1991 to 2000, were considered. The area in which forestry operations were conducted declined by almost 50% over the 10-year study period, and amounted to less than half of the area targeted in the local Forest Improvement Plans. The mean access distance to work sites was 156 m in Shitara and 164 m in Toei, 55 m and 52 m less than the 10-year averages for each entire forest (211 m and 216 m), respectively. The mean slope of the work sites was almost the same as that of each entire forest, for both areas. To improve present forestry conditions, increased road access would be required; road densities would have to increase by 8.1 m/ha for Shitara and 7.1 m/ha for Toei. Forest conditions and temporal changes were further analyzed using both cluster and discrimination analyses of forest resources, forest improvement, and road access factors; four categories of forest were subsequently identified: well managed and accessible, poorly managed despite accessibility, poorly managed and accessible, and mature forest not needing tending.

View full abstract