Blog Post 4: Sampling Strategies

The three sampling strategies that I used in the Snyder-Middleswarth Natural Area virtual forest tutorial were (1) area- based systematic, (2) area-based random and (3) haphazard or subjective sampling.

The systematic sampling technique had the fastest estimated sampling time of 12 hours and 6 minutes.  Random based sampling had an estimated sampling time of 12 hours and 50 minutes.  Haphazard or subjective sampling had an estimated sampling time of 12 hours and 36 minutes.

For the sampling the two most common species ended up being Eastern Hemlock and Sweet Birch.

Eastern Hemlock percent error for systematic sampling was 8.7% compared to 14.0%for random based and 8.2% for haphazard sampling.  Sweet Birch percent error for systematic sampling was 46.8% compared to 22.0% for random based and 41.9% for haphazard sampling.

The two rarest species were Striped Maple and White Pine.

Striped Maple percent error for systematic sampling was 4.6% compared to 100% for random based and 4.6% for haphazard sampling.  White Pine percent error for systematic sampling was 7.1% compared to 7.1% for random based and 39.0% for haphazard sampling.

As species abundance decreased one should have expected that overall accuracy would have decreased as well but my virtual sampling numbers did not clearly identify a definitive trend in this respect as my percent errors varied quite a bit.  Although there was one spike in the percent error systematic sampling seemed to be more accurate.  If a larger number of samples were taken I predict that the percentage errors would be much lower as a more representative sample of the forest would have been taken.

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