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Blog post 4
For the virtual tree sampling experiment, three methods were used: systematic sampling along a topographic gradient, random sampling, and haphazard sampling. The fastest sampling technique was the systematic sampling along a topographic gradient which took 12 hours, and five minutes to complete. The tables present the two most common and rare species found during the different sampling techniques. It was also found that the systematic sampling technique along a topographic gradient had the highest accuracy for the sampling of common species. The random sampling of the tree species (Table 2.) had the highest accuracy and precision for the rare species in the tests. The haphazard sampling technique (Table 3.) had the lowest accuracy overall for both common and rare species. The overall accuracy was not affected by the species abundance in the studies. The results from the second field study (Table 2) had the highest accuracy overall for all three of the studies.
Table 1. Systematic sampling of tree species along a topographic gradient at Snyder-Middleswarth Natural Area.
| species | # of individuals | density (stems/ha) | Percent error |
| Eastern Hemlock | 141 | 96 | 25.80% |
| Yellow Birch | 47 | 108.9 | 42.10% |
| Striped Maple | 4 | 16 | 8.57% |
| White Pine | 4 | 16 | 90.50% |
Table 2. Random sampling of tree species at Snyder-Middleswarth Natural Area
| species | # of individuals | density (stems/ha) | Percent error |
| Eastern Hemlock | 152 | 633.3 | 34.70% |
| Yellow Birch | 35 | 145.8 | 33.98% |
| Striped Maple | 4 | 16.7 | 4.57% |
| White Pine | 2 | 8.3 | 1.19% |
Table 3. Haphazard sampling of tree species at Snyder-Middleswarth Natural Area
| species | # of individuals | density (stems/ha) | Percent error |
| Eastern Hemlock | 155 | 645.8 | 37.43% |
| Sweet Birch | 48 | 200 | 70.21% |
| Striped Maple | 2 | 8.3 | 52.57% |
| White Pine | 1 | 4.2 | 50.00% |
