User: | Open Learning Faculty Member:
Adrienne Burns
August 21, 2019
The first sampling method I conducted was the ‘Area; Systematic” approach. I choose one randomized number ‘y’ axis, and received my subsequent data from adding 10 to each of the ‘x’ axis and alternating between the randomized number and ‘y+10’. The density data from this sampling method has some very accurate of methods for certain species of trees, but very inaccurate data for others. When comparing it to the ‘Actual density’ data, for example, the actual density of Sweet Birch was 117.5, and sampling density found 116, and for White Pines species, the actual density was 8.4 and the data showed a density of 28.0. I found it interesting that for the species Striped Maple, this method did not count any of the trees. The density for Striped Maple was 17.5 and this method accounted for 0.0. This type of sampling didn’t correctly depict the distribution of tree species over the entire forest area. Also, the ‘Area; Systematic’ method took a long time to complete. It took 12 hours and 35 minutes to complete the sampling.
The second method was the ‘Distance; Random’ sampling technique. This method had given me 24 random ‘x, y’ axis to sample. It was the fasting sampling method which took 4hr 38minutes. This would be the preferred method of sampling if the ecologist had time constraints. Along with the first method this one also showed varying correctness for the distribution of the trees. For example the actual Hemlock density was 469.9 and the data showed a density of 445.1, but for the Red Maple the actual density was 118.9, but the data showed 145.2. Of all 3 of the sampling methods I used, the ‘Distance; Random’ technique was the most accurate especially with regards to frequency.
The last method, ‘Area; Haphazard’ took the longest timeframe to complete 13h and 1minute. It also had the largest variation in results. For instance, Eastern Hemlock actual density was 469.9. Both ‘Area: Systematic’ and ‘Distance; Random’ data were close in proximity to 440.0 and 445.1, yet the ‘Area; Haphazard’ showed 669. As it had the largest variation and the longest timeframe, I would need to seriously consider I was going to use this method.
None of the methods were very accurate. All had some tree species data that was accurate, and others that were far from the actual data.
Error Percentage Eastern Hemlock
‘Area; Systematic’
(440-469.9)/ 469.9*100 = 6.36% Error
‘Distance; Random’
(445.1-469.9)/469.9*100 = 5.28% Error
‘Area; Haphazard’
(664.0-469.9)/469.9*100 =41.31% Error
Error Percentage White Pine
‘Area; Systematic’
(28-8.4)/8.4*100 = 233.33% Error
‘Distance; Random’
(9.7-8.4)/8.4*100 = 15.48% Error
‘Area; Haphazard’
(4.0-8.4)/8.4*100 = 52.38% Error
