Because different tree parameters are of differing importance, and have different variability, efficiency in sampling would suggest that some of the principle variables be subsampled. One convenient way to do this is ...
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Because different tree parameters are of differing importance, and have different variability, efficiency in sampling would suggest that some of the principle variables be subsampled. One convenient way to do this is to sample different numbers of items at the same sample locations. This paper is a review of some current techniques in subsampling for measured values, especially with variable plot sampling, but including Fixed plot and 3P sampling as well.
Big basal area factor (BAF) sampling techniques were investigated in a 70-year-old even-aged hardwood forest in northern West Virginia. Data collection procedures permitted the investigation of several small BAFs when...
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Big basal area factor (BAF) sampling techniques were investigated in a 70-year-old even-aged hardwood forest in northern West Virginia. Data collection procedures permitted the investigation of several small BAFs when employed with 12 big BAFs ranging from 55 to 300. Mean board foot volume per acre for sawtimber products was investigated along with a comparison of the resultant standard errors. The estimated mean volume per acre was quite stable. The same approximate mean volume per acre was obtained using big BAF values of 55 and 150 but with a 66% reduction in the number of sample trees needed for volume estimation. sampling error increased with increasing big BAF, especially above values of 150. sampling error within a single big BAF value was stable across the range of small BAFs sampled.
A new approach is suggested here for estimating stand attributes when horizontal point clusters (HPCs) are used. The approach is unbiased with smaller variance than the traditional unbiased estimator for HPCs. The nec...
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A new approach is suggested here for estimating stand attributes when horizontal point clusters (HPCs) are used. The approach is unbiased with smaller variance than the traditional unbiased estimator for HPCs. The necessary formulas for equidistant 3-point clusters are derived. The new estimator offers an opportunity to reduce variance without changing the sample design. For. Sci 35(1):257-262.
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