Growth and yield estimation using temporary variable plots
1993
Rustagi, K.P.
A sampling procedure for stand based management purpose inventory is presented in which volume is computed as the product of the average basal area per hectare and the average volume basal-area-ratio. The basal area estimate is obtained from temporary variable plots, and the average volume-basal-area-ratio is obtained from a subsample of point sampled trees. Expression for the variance of the product estimate is also given. Simulated tests on two Douglas fir (Pseudosuga menziesii (Mirb.) Franco var. menziesii) stands show that for the same degree of precision, fewer trees need to be measured for volume while using this sampling technique over the double sampling for ratio estimate. The number of sample trees by species or size class may be fixed independently of their relative frequencies. By post stratifying the point sampled trees, it is possible to obtain separate estimates by species and/or size classes together with their variances, thus making this sampling procedure suitable for multispecies stands. The growth estimates may be derived as the difference between two successive inventories
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