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I used the distance-based method for the Sampling Theory Using Virtual Forests Tutorial. Below is a table summarizing the comparison between the actual and estimated densities of the seven tree species in the Snyder-Middleswarth Natural Area as well as the percentage error using each (distance-based) sampling method. Also included in the table is the estimated sampling time for each method.
Based on the results above, the systematic method had the fastest estimated sampling time.
The two most common species are the eastern hemlock and red maple while the two rarest species are the striped maple and white pine. Between the three different strategies, percentage error is generally inversely related to species abundance. This is more prominently seen in the random sampling strategy.
When we only look at the most common and rarest tree species, the haphazard approach is the most accurate. However, when we consider all tree species, the systematic approach is the most accurate with a maximum percentage error of 57.7% versus the 100% error with the haphazard approach for the striped maple.
Overall, the systematic approach is best because of its relatively lower sampling time and for its relatively higher accuracy.
