Conifers like pine, spruce, fir, cedar, juniper support insects (like this spruce budworm at left), and many birds forage in conifers. But until recently, Caterpillars Count! focused only on broad-leaved trees for survey branches. This is because our survey protocols traditionally only used number of leaves to characterize the amount of branch examined. However, this does not work so well for conifers because:
- for a visual survey, 50 conifer needles is not a large enough section of branch to yield a reasonable sample of arthropods, and
- for a beat sheet survey, users cannot be expected to accurately estimate the total number of (e.g., tiny spruce) needles above a beat sheet.
Thus, for coniferous branches only, instead of surveying an area of 50 leaves or counting the number of leaves over the beat sheet, you will estimate the linear branch length sampled.
- Linear branch length sampled is the sum of the lengths of all of the branchs and twigs examined.
- For a visual survey, we suggest examining between 100-300 cm of branch and twigs, including all of the component needles. Whichever total length works well for you, we ask you to be consistent and use it for all of your visual surveys on conifers, if possible.
- For a beat sheet survey, after beating the branch and entering your arthropod observations, you will estimate the sum of the linear branch length sampled as in the animated figure below.
As a reminder, the tree species surveyed at your site should be representative of the vegetation found there, with branches chosen as described here. This could mean your branches are entirely broad-leaved, a mix of broad-leaved and coniferous, or entirely coniferous. For any branches with broad leaves, follow the regular instructions as described on this page.