📅 Timing: Complete at your own pace by 30 November 2026.
ℹ️ Description: Learn how a simple relascope is used to estimate forest stand basal area. This practical forest demonstration shows how to hold the instrument, sight trees at breast height and decide whether a tree counts as 1, 0.5 or 0.
📄 The learning material: A 2 minute 20 second video with original Estonian narration, English subtitles and explanatory diagrams. The English subtitles are already visible in the video. Allow approximately 10–15 minutes for watching and reflection.
🎯 Learning outcomes: After studying the material, you should be able to:
- Explain why the distance between your eye and the relascope must stay constant.
- Distinguish the counting examples 1, 0.5 and 0 by comparing the apparent width of the tree stem with the opening.
- Describe a full 360° sweep and explain why measurements are repeated at several sampling points.
📝 Self-study task: Watch the video once, then pause at the three counting examples (approximately 1:01–1:23). Explain each decision in your own words. What would change if the instrument moved closer to your eye? Why might one sampling point give an unrepresentative result?
Field practice: Apply the sampling and borderline-tree rules specified for your own field exercise. Use the video as a demonstration alongside your instructor’s measurement protocol.