Lesson plan
Borderline tree
Borderline tree is a term used in forestry. It is a concept that comes from variable radius plots, or point sampling. It happens when a tree cannot be easily determined as in or out when using a prism or angle gauge. Borderline trees occur only when the distance from the sampling point to the center of the tree is equal to the DBH times plot radius factor (PRF). The PRF is determined based on the type of prism or angle gauge being used. Basal Area Factor (BAF) 5, 10, and 20 angle gauges result in PRFs of 3.89, 2.75, and 1.94 (feet inch −1 ) respectively. The metric equivalents of these PRFs are 0.467, 0.33, and 0.233 (m cm −1 ). When a tree is borderline, a series of measurements and calculations must be made to determine if the tree is in or out. The horizontal distance from the sampling point to the center of the tree must be measured along with the DBH of the tree. The DBH should then be multiplied by the PRF, which will give a limiting distance. If the measured distance is less than or equal to this limiting distance, the tree is counted as in. If it is greater than the limiting distance, it is out.
Article summary
Borderline tree is a term used in forestry. It is a concept that comes from variable radius plots, or point sampling. It happens when a tree cannot be easily determined as in or out when using a prism or angle gauge. Borderline trees occur only when the distance from the sampling point to the center of the tree is equal to the DBH times plot radius factor (PRF). The PRF is determined based on the type of prism or angle gauge being used. Basal Area Factor (BAF) 5, 10, and 20 angle gauges result in PRFs of 3.89, 2.75, and 1.94 (feet inch −1 ) respectively. The metric equivalents of these PRFs are 0.467, 0.33, and 0.233 (m cm −1 ). When a tree is borderline, a series of measurements and calculations must be made to determine if the tree is in or out. The horizontal distance from the sampling point to the center of the tree must be measured along with the DBH of the tree. The DBH should then be multiplied by the PRF, which will give a limiting distance. If the measured distance is less than or equal to this limiting distance, the tree is counted as in. If it is greater than the limiting distance, it is out.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.