Effect of Tree Diameter and Number of Boreholes on Oleoresin Yield in Pinus Roxburghii Sargent

The oleoresin is an important forest produce of pine forests in the world. The conventional rill method of tapping leads to the destruction of some wood and the production of poor quality oleoresin. The improved tapping technique i.e. borehole method was used by applying 10% ethephon and 20% H SO as a stimulant. The mean oleoresin yield of low, 2 4 medium and high resin yielders was 827.24, 1486 and 2594.8 g/season respectively. The highest oleoresin yield was recorded in R-11 high resin yielder (3975 g/season) and lowest oleoresin yield was found in R-20 low resin yielder (465 g/season). The highest oleoresin yield of 2.24 kg was recorded in 40-45 (D ) diameter class. The oleoresin yield differed 3 significantly among the different boreholes drilled at different time interval. The maximum oleoresin yield of 684.5 g/hole/tree was obtained from first (B ) borehole (March to October) and minimum oleoresin yield (523.4 g/hole/tree) 1 was recorded in B (May-October).