Author: Ghent, A. W.

Source: Forest Science, Volume 9, Number 3, 1 September 1963 , pp. 295-310(16)

Publisher: Society of American Foresters

Abstract:

The precision of estimates of Abies balsomea (L.) Mill. populations is adequately described by the rectangular hyperbola that relates standard error and sample size in elementary statistical theory. With sample size held constant, standard error is found to be a power function of density, of the form Y.X^a = b. Inspection of standard error vs. sample size hyperbolas at selected population densities demonstrates that the sampling effort required to attain a given level of precision varies inversely with density. The roles of competitive and non-competitive influences upon seedling distributions are considered. A new method of applying the binomial to the assessment of contagion demonstrates that areas of both very high and very low seedling densities are contagiously distributed, while areas of intermediate density are more randomly dispersed. Studies of the influence of observational scale upon the apparent distribution of A. balsamea seedlings show this to be independent of quadrat size over the range from 0.25 to 2.25 milacres. The apparent distribution changes dramatically, however, with changes in the total area over which the quadrats are spread. Disagreement with the Poisson distribution, rather than agreement with the negative binomial or other variance-dependent distribution, is found to be the more reliable criterion of contagion. Unlike A. balsamea, Pinus strobus L. seedling distributions do show a change in apparent distribution with increasing quadrat size, and illustrate the convergence of the negative binomial to the Poisson distribution as mean and variance approach equality.

Document Type: Journal article

Affiliations: 1: Dept. of Zoology, Univ. of Okla.

Publication date: 1963-09-01

More about this publication?

• Membership Information
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Forestry
• By this author: Ghent, A. W.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers