What you need
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Perspex disc approximately 30cm diameter with a ruler shaped slot cut in the middle
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Half metre or metre rule
What you do
Ask your DT department or local DIY store to cut out your Perspex discs to your specifications and drill out the rectangular hole in the centre. Ensure that the hole is large enough to slot a half meter or a meter rule through. Place the zero end of the rule on the ground and drop the Perspex disc down over it. The disc will find the average level of the vegetation sward. Record the measurement from the rule.
When you use it
This home made drop disc is used to measure variations in vegetation sward height across a site or between sites. Adding a grid to a clear Perspex disc will enable percentage coverage of vegetation or particular species to be calculated at the same time.