| УДК |
Аннотация: Solar radiation was measured during three months in the summer of 1961 by means of Bellani pyranometers below the canopy of three balsam fir stands, one unthinned and two recently thinned, in Quebec. Observations were made at three randomly selected stations representing average values at each plot. Radiation available below canopy was related to physical dimensions of stands. The average solar radiation beneath fir canopies showed values of 6,8, and 10 per cent of that in the open for stands of 7,600, 5,900, and 4,489 inches of stem density, respectively. Variations in the amount of solar radiation in the open did not change the average percentage of open radiation in the stands. However, with increasing amounts of radiation in the open the scatter of values around the mean percentage of open radiation decreased. It was estimated that thinnings that removed 12 and 36 per cent of the original stand basal area had the immediate effect of increasing the radiation intensity by 25 and 50 per cent.
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