Virtual forests tutorial:
Three sampling techniques used: systematic, random, and haphazard.
Fastest estimated sampling time: The systematic technique, at 4 hours and 15 minutes.
Two most common species: Eastern Hemlock and Sweet Birch
Two rarest species: White Pine and Striped Maple
Percent Error
Sampling Technique Eastern Hemlock Sweet Birch White Pine Striped Maple
Systematic -19.7 -7.2 -100 -4.0
Random -28.4 -32.3 -100 -100
Haphazard 92.3 81.8 486.9 -6.3
(Based on density values)
The accuracy was better for the more abundant hemlock and birch species. Although the Striped Maple is rare, the systematic and haphazard techniques had good accuracy for the species. This may be due to its distribution. The haphazard strategy sampled areas with high concentrations of trees, increasing the likelihood of finding the maples. The systematic strategy sampled a narrow transect across the site. It is possible that it happened to run through locations with maples and that if the transect had been further east or west, it would have missed those maple-rich locations, and the percent error would have been much higher using the systematic technique for the rare Striped Maple species. Overall, accuracy is better for more abundant species than for rare species, based on this data.
The systematic technique had the lowest error for all four species, making it the most accurate and efficient sampling strategy. The haphazard technique had the highest percent error for three of the four species (all except the maples), making it the least accurate sampling strategy in this exercise.