User: | Open Learning Faculty Member:
Blog Post 4: Sampling Strategies
The results of the sampling strategies for the virtual forest tutorial are summarized in Table 1 at the bottom of this post.
The sampling strategies did not vary greatly in terms of time spent sampling, however, the most efficient was the systematic sampling method. This method took 12 hours, 38 minutes as opposed to 12 hours, 43 minutes and 12 hours, 55 minutes for the other two sampling methods.
The accuracy of sampling varied for the most and least common species, depending on the sampling strategy used. The most accurate sampling strategy for the most common species (i.e. eastern hemlock) was the systematic method. The most accurate sampling strategy for the rarest species (i.e. white pine and striped maple) was the haphazard sampling method. The accuracy was lower for the rare species across all sampling strategies. The range of percent error across sampling strategies for eastern hemlock was 10.66-22.37 %, while for white pine this jumped to 42.86-52.38 %.
Overall, the haphazard sampling strategy was the most accurate as this had the smallest percent error averaged across the species (4.03), while the percent errors for the systematic and random sampling strategies were 17.92 and 29.87, respectively.
Table 1: Results of the virtual forest sampling strategies
| Sampling Strategy: | Systematic | Random | Haphazard | ||||
| Species | Actual | Estimated | % error | Estimated | % error | Estimated | % error |
| Eastern hemlock | 469.9 | 520 | 10.66 | 575 | 22.37 | 540 | 14.92 |
| Sweet birch | 117.5 | 124 | 5.53 | 79.2 | -32.60 | 108 | -8.09 |
| Yellow birch | 108.9 | 92 | -15.52 | 58.3 | -46.46 | 116 | 6.52 |
| Chestnut oak | 87.5 | 92 | 5.14 | 62.5 | -28.57 | 92 | 5.14 |
| Red maple | 118.9 | 144 | 21.11 | 150 | 26.16 | 144 | 21.11 |
| Striped maple | 17.5 | 0 | -100.00 | 0 | -100.00 | 8 | -54.29 |
| White pine | 8.4 | 4 | -52.38 | 4.2 | -50.00 | 12 | 42.86 |
