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During the virtual forest tutorial, three sampling strategies were used to compare the abundance of different tree species throughout Middleswarth Natural Area. These strategies were the haphazard strategy, the random sampling strategy, and the systematic sampling strategy. I chose to sample by area not distance for the tutorial.
After completing the tutorial, it is estimated that the haphazard strategy was fastest for sampling (12 hours, 29 minutes) followed by the systematic sampling strategy (12 hours, 37 minutes), and the random sampling strategy taking the most time (12 hours, 42 minutes).
For the systematic sampling strategy, the percent errors for the two most common species were 20.2% and 31.2%, while the percent error for both of the two least common species was 100%. For the random sampling strategy, the percent errors for the two most common trees were 4.6% and 8.9%, while the percent error for the two rarest species were 100% and 50%. Finally, the percent errors for the two most common species using the haphazard strategy were 7.8% and 40.5%. The percent errors for the two most rare species were 4.6% and 100%. A percent error value of 100% occurred when no trees of those species were found during the sampling. From this, it can be observed that the lowest percent errors were found by using the random sampling strategy on the most common tree types, while the largest percent errors occurred when systematically sampling the least common species. Even more generally, the systematic sampling strategy yielded an overall percent error of 62.9%, the random sampling strategy yielded 40.9%, and the haphazard strategy yielded 38.2%. From these results, if one strategy had to be used, the haphazard strategy would yield the most accurate data on average.
Generally, as the abundance of a certain species decreased, the percent error increased. This indicated a decrease in accuracy, as the degree of closeness between measured and true values decreased. Conversely, the more accurate data was found in the samples of the most abundant tree types. The most accurate strategy for sampling the most common tree species was the random sampling strategy, and the most accurate strategy for sampling the rarest tree species was the haphazard strategy. It should be noted that the average percent error for the rare species was still much larger than the average for common species. Thus, it is important to understand the expected density and abundance of the species of interest to choose the sampling strategy that will yield the most accurate data. From this tutorial, it is evident that best strategy may not be the same for sampling all tree types. Ensuring the proper strategy is used will allow for sampling data to best represent the population data.
