A Monte Carlo Study of Distance Measures in Sampling for Spatial Distribution in Forest Stands
Abstract:Two rules using distance measures are studied: (1) the measurement from a random point to the tth nearest tree and (2) the measurement to the tth nearest tree in each of 4 sectors. First a statistical framework was developed to determine their performance characteristics and both theoretical and intuitive estimators of the number of trees and basal area per acre to use with them. Three hypothetical but typical forest patterns of 100 trees each are examined. A computer program was used to produce the frequency distributions. For this paper t ranged from 1 to 4. Edge effect was discussed but only those sample points free of edge effect were used in the analysis. The frequency distributions generated were compared with 5 common mathematical distributions. No statistically significant fit was found. All estimators are shown to be biased. On the basis of this study it is possible to use these rules to separate areas based on pattern and density. The variance of the average distance from a random point to the tth nearest tree is an indicator of pattern and the average distance is an indicator of density. With either of these rules it seems unlikely that unbiased estimators of density or basal area can be developed for most nonrandom biological populations.
Document Type: Journal Article
Affiliations: Instructor in Forestry, Dept. of Forestry and Wildlife Management, University of Massachusetts, Amherst
Publication date: 1968-06-01
More about this publication?
- Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
Forest Science is published bimonthly in February, April, June, August, October, and December.
2015 Impact Factor: 1.702
Ranking: 16 of 66 in forestry
Also published by SAF:
Journal of Forestry
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