Forest Research 0 - 50mm diameter calipers
These plastic calipers were produced by the Forest Research workshop, Alice Holt, for the accurate measuring of tree stem and root collar diameter; the former at specific distances from the root collar.
These measurements were mainly carried out on transplants in the forest nursery setting, or during the initial establishment of the transplants in an experiment, or in the plantation; nutrition experiments being the most usual, scenario.
However, I did also use them to assess root collar diameter and stem diameter when assessing large pine weevil (Hylobius abietis) infestations on re-stocking sites and the efficacy of various control treatments. This was to assess whether tree root collar and stem diameter affected the feeding preferences of the weevil. The hope being that the larger the stem diameter, the more weevil bites could be sustained before the stem was girdled and the tree killed, permanently disfigured, or coppicing from the base to produce multiple stems, rather than a single stem.
Groups: Forest Nurseries, Forest Research, Tools, equipment and clothing