Log Sampling Methods and Software for Stand and Landscape Analyses
serial correlation test, shown on the Summary Statistics page, indicate that adjacent
segments are independent (r = 0.126; r
Once the Volume page is activated, enter the area of stratum 1 (812) in the box
labeled “Landscape Area.” Results show that stratum 1 contains an estimated 39.3
± 14.2 m
/ha. Precision is 36.1 percent. Print the results on the Volume page for use
on the Combination page at the end.
Results for large (≥25 cm LED) logs in stratum 1, using the same analytical
process, yields a volume of 33.8 ± 14 m
/ha. Precision is 41.4 percent. Segments
provide the most precise measurement and are independent (r = 0.134; r
Estimated sample size required equals 4270 m. Print the results on the Volume page
for use on the Combination page.
Stratiﬁed volume analysis—
To obtain a stratiﬁed volume estimate using both the LIM and SPM sampling
methods, the statistics expressed in a per-unit basis from each Volume page gener-
ated above, must be entered onto the Combination page. To do this:
1. Click on Combination from the Method menu.
2. Click Yes to change the method.
3. Click Volume from the Formula menu.
There are two sheets available on the Combination page. Shaded boxes require
input from users. The Parameter Estimate page (ﬁg. 18) uses a stratiﬁed-random
sampling equation to calculate a mean, bound, and precision for measurements
expressed in a per-unit basis (hectares or acres). The Sample Sizes page provides
the Estimated Sample Size Required for estimates expressed in hectares or acres.
Follow these steps to obtain an estimate of log volume (≥15 cm LED) for the
entire subwatershed using the results printed out for each stratum:
1. Enter the numbers “1,” “2,” and “3” under the heading Stratum.
2. Under the heading Transect Section Names select Segment, Subsegment,
and Segment from the drop-down menu for strata 1, 2, and 3, respectively.
3. Enter the numbers “812,” “654,” and “490” for number of hectares in strata
1, 2, and 3, respectively.
4. Enter the estimated volume of logs per hectare for each strata under the
heading Parameter Estimates. For strata 1, 2, and 3 there were 39.3, 72.8,
and 145 m
5. Enter the estimated variance for strata 1, 2, and 3. These values were 2884,
14,027, and 5,370, respectively.
6. Enter the number of samples for each stratum. This should be 40, 80, and
40 for strata 1, 2, and 3, respectively.