. A primer on stand and forest inventory designs. Forests and forestry Mensuration; Forest surveys. If the initial point falls close to the edge of the stand, some subplots may fall into adjoining stands. When validation of the mapping or classification is important, substitute plots established according to previously defined rules are normally used (fig. 9). In the inventory of stand 97, a 10-point cluster is estab- lished as shown in figure 8. Each subplot represents about acre. Statistical Estimates—A good deal of care must be taken in the consideration of the statistical nature of th
. A primer on stand and forest inventory designs. Forests and forestry Mensuration; Forest surveys. If the initial point falls close to the edge of the stand, some subplots may fall into adjoining stands. When validation of the mapping or classification is important, substitute plots established according to previously defined rules are normally used (fig. 9). In the inventory of stand 97, a 10-point cluster is estab- lished as shown in figure 8. Each subplot represents about acre. Statistical Estimates—A good deal of care must be taken in the consideration of the statistical nature of the estimates. For some sample clusters it is possible that a mean and variance for the stand would be meaningful. This is probably not the case for the example. The results of the inventory of stand 97 using a single 10-point cluster are as follows: Subplot ccf per acre 1 17 2 17 3 17 4 17 5 16 6 15 7 17 8 17 9 17 10 17 There are N - 75 1-acre plots if each cluster occupies about 1 acre. y - (17+17+ . . 17)/10 - ccf per acre. sy2 - {(172+ 172+ . . 172)-(17+ 17+ . . 17)2/10}/ (10-1) = s7* - {()*[1 -(10/750)]}1/2 - ccf per acre. As this represents a single cluster the sampling formula without replacement of points is applied. Values for estimated percent error and total stand volume are com- puted as: %se - () * 100 = ± %. Y = *75 = 1, ccf for the stand. This estimate should carry very little more weight in terms of actual information about the stand than a single point, and you may notice that it is not a very accurate estimate of the stand's true volume. Cost Estimates— Like the single plot estimate for a stand, the cost can be computed, but its informational value to an inventory forester is minimal. For a single cluster, n = 10, i = 70 feet. L = [(10 - 1)70]/10,560 = hour. D = [ + 10()1/8 = hour. F = 2(9) [ + 10() + ] = $, or $ per Figure 9—Location of substitute sub
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