Point sampling and line sampling : probability theory, geometric implications, synthesis /

Abstract

Foresters concerned with measuring tree populations on definite areas have long employed two well-known methods of representative sampling. In list or enumerative sampling the entire tree population is tallied with a known proportion being randomly selected and measured for volume or other variables. In area sampling all trees on randomly located plots or strips comprising a known proportion of the total area are selected and measured for volume or other variables. List or enumerative sampling is commonly used in timber sales employing sample-tree measurement, and area sampling in timber reconnaissance. Each method, in its simplest valid form, operates to give every tree in the studied population an equal chance of being selected. A class of trees, therefore, can expect to be sampled in proportion to the frequency of trees in that class, and the frequency of a single tree is one.