FOREST LAND-USE AND PRODUCTION STUDIES OF PHU-LUANG FOREST

Abstract

A study of natural resources and land use of Phu-Luang Forest at Pakthongchai Distric, Nakhonratschasima province is made by utilizing black and white aerial photographs of 1:15,000 scale. Aerial photography was conducted during the year 1975 and 1977. The aerial photographs were used for a compilation of the study area land use map and also used for supplementary tools for forest inventory in the study site.

Line plot sampling method with 2.5 percent of cruise was used for this purposes. Along the line concentric sample plots with 17.84, 12.61 and 5.64 m in radius were systematically laidout. All tree with the Diameter at Breast Height (DBH) over 30 cm were talley in the outer circle. Total height and commercial height at the lowest living brance were measured by using Haga Hypsometer. The middle circle of 12,61 m in radius (0.05 ha) was used to enumerate the poling which having DBH less than 30 cm and taller than 1.30 m. The inner circular plot of 5,64 m, in radius (0.01 ha) was also used to evalate natural regeneration by enumeration of seedlings and saplings (trees having height less 1,30 m.)

Likewise the existing conditions for instance, forest disturbance, crown density, vertical layer, evidence of fire etc, were evaluated and recorded.

The results of the study show that the study area of 89.97 km²(56,229.50 rais) are classified into undisturbed dry evergreen forest 6.59 km² (7.32 %) of the total area. This forest ecotype has the Hopea ferrea, Hopea odorata, Afzelia xylocarpa and Largerstroemia calyculata as the dominant species. Evidence from the analysis of this forest type is the total number of trees is 104,916 or 159 trees/ha. The total commercial volume is 63,211.28 m³ or 95.92 m³ per hectare. Valuation of stumpage value (values of standing timber) by overturn method shows that the total merchantable trees in this forest type are valued at 20,616,476 baht, averaging 31,284 baht per hectare. It is found that the production of this area is lower than in the same forest ecotype at Sakaerat Environmental Research Station.

It is found that the polings or trees of smaller size in the of 279,139, an average of 424 trees per ha and the total saplings and seedling are 132,000, an average of 200 trees per ha.

Other land use found in the area are disturbed dry evergreen forest 1.48 km² (1.64 %), agricultural land 53.04. km² (58.96 %), swidden area 28.80 km² (32.01 %) and water resources 0.06 km² (0.07 %)

Study of socioeconomic factors in the study area found that the study site were heavily deforested due to illegal encroachment of forest lands for field crops planting, illegal timber cutting and charcoal industry which made a decline of national reserved forests.