Method Narrative  |
From the text: "These analytic plots are similar to those used by Daubenmire (1959). Each macroplot is 25 m long and 15 m wide. In all cases the macroplots were placed perpen- dicular to the direction of stream flow of the McKenzie River or its subsidiary channels. This plot orientation was for uniformity only. Since the terrain averaged only 1 o slope downstream over the length of the study area, there was no obvious reason for placing plots other- wise, nor did sufficient variation occur within stands to warrant any special placement patterns.
Since the floodplains and terraces are of restricted area, placement of groups of plots was necessary. Therefore, most terraces and floodplains have been sampled with two or more plots each. Each plot occurs between 35 and 100 m from the nearest plot in the same group. In highly homogenous areas wider dispersion of plots in a group increases the likelihood of sampling the range of variation. In more heterogeneous areas it emphasizes the amount of variation that can occur due to environmental changes over short distances. At each analytic macroplot noticeable drainage peculiarities were
recorded. The slope over approximately 30 m was measured with an Abney level. The elevation of each plot was estimated using topographic maps and bench marks, and each plot was located by section, township, and range using the U.S. Geological Survey quadrangle maps. Macroplots were laid out by selecting a location for the first corner, which was always the upstream corner on the closest end to the stream, and then stretching out a line that had been measured and marked to delimit a plot 25 m by 15 m.
Each macroplot was then divided in accordance with the method used by Daubenmire (1959). Within each of three sections, each 25 m by 5 m, every tree over 1 m tall was recorded by species and diameter at breast height (DBH). Those trees between 1 m tall and breast height (1. 37 m) were given a DBH of 1 cm. The estimated maximum crown radius was also recorded for each tree.
In a 1 m wide strip outside of each subdivision line, along the length of the macroplot, trees less than 1 m tall were recorded by species and height (dm). On the inside of each of the subdivision lines 25 microplots were taken at 1 m intervals for a total of 50 per macro- plot. Each microplot was 20 cm by 50 cm. Use of a painted, steel plot frame aided in cover estimation (Daubenmire, 1959). Within each of the 50 microplots the shrubs, herbs and mosses were recorded by species and percent coverage. Microplots which fell on rock outcrops, logs, or standing trees were classified as special microhabitats and the vegetation, usually mosses, was not recorded."
|
