COMPARISION OF TECHNIQUES FOR LEAF AREA INDEX ESTIMATION IN ALSTONIA SCHOLARIS R.BR. PLANTATION

Abstract

There are several techniques in measuring leaf area index of stand. The objective of the present study was to compare different techniques in estimating leaf area index including, clip method, hemispherical photography and plant canopy analyzer (LAI 2000). The study was carried out in 3-year-old Alstonia scholoaris R.Br. Plantation at Trat Agroforestry Research Station, Muang District, Trat Province, with 3 different densities i.e., 40,000, 10,000 and 2,500 trees per hectare (6,400, 1,600 and 400 trees per rai) respectively. The results showed that leaf area index estimated by hemispherical photography gave the highest value, since it was actually the value of canopy arca index of which branches and stems were included. Using different techniques in leaf area index estimation were not different statistically in 40,000 and 2,500 trees per hectare plots, but different statistically in 10.000 trees per hectare plot. The results implied that any techniques can be used for leaf area index determination if the canopy is evenly distributed without large gap. If the canopy is not evenly distributed, clip method which is the direct method for leaf area determination is probably provided the best result. If hemispherical photography and plant canopy analyzer are used, more samples must be considered Advantages and disadvantages of these three techniques were discussed in details in the present study