More efficient resin production from Pinus roxburghii (Chir pine)
More efficient resin production from Pinus roxburghii (Chir pine)
Mahmood Iqbal Sheikh
ABSTRACT
The study was started with a view to increase the resin output from Chir pine (Pinus roxburghii) forests. 500 trees 27.5 to 40 cm in diameter were selected at two different sites. In the first year i.e., 1974 all the trees were worked under French system of tapping for the
purpose of calibration of yield. At the end of the tapping season, progressive increase in the yield was indicated with the increase in diameter. Some trees turned out to be natural high yield. In 1975, use of chemicals was introduced. 10% sodium chloride solution, 40% sulphuric acid solution and 60% sulphuric acid past were used. Whereas for sulphuric acid past and solutions, American bark chipping method was employed, for the purposes of control and sodium chloride solution, French blazes were used. It was found that 40% sulphuric acid solution provided maximum simulation; the yield under this treatment was the highest. The trees were subjected to the same treatment during the year 1976 and 1977 and the results of first year were confirmed. As compared to the control the resin yield
was almost double by the application of 40% sulphuric acid solution. In year 1977, only the treatment was continued on the old 500 trees but also another set of 225 trees was selected as an adaptation of the American method to suit the existing management and silvicultural
requirements of chir forests in Pakistan. Only one stimulant i.e., H2SO4, 40% and 50% in solution form was
used and compared with the French method (control). The major change was that the annual face width was not kept equal to diameter of tree but only 15cm. In the experiment, also 40% sulphuric acid solution gave the best result, the average yield per tree being 3.7 kg as
compared to the control, 1.5 kg.
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March 1978
Vol. 28, Iss. 1
