Methods of investigating the Fauna of Tree-stumps

Extract

Ever since forest entomologists began to inquire into the interrelation between the action of the forester and the prevalence of noxious insects, the pine weevil (Hylobius abietis) has been quoted as a classical example of what unfortunate results large clean cuttings and planting on and in the vicinity of the cut-over areas may produce. This is due to the fact that the females oviposit under the bark of the stumps, where the larvae make their long tunnels far down into the roots of the trees and that large clean cuttings offer them greatly increased facilities of ovipositing in suitable places. At the same time the great number of young pine—or spruce-plants—offer the emerging weevils plenty of tender and nourishing food. The same thing happens if in the vicinity of a successful plantation an area is cut over ; the only difference being that in this case the young plants are attacked in the spring following the cutting by weevils attracted by the smell of the stumps but not yet sexually mature until they have fed on the young plants, whereas in the former case the injury appears 2–3 years after the cutting, when the beetles of the next generation appear.