Aim to prune 100 - 200 trees per acre in natural stands and 350 per acre in pure white pine plantations. It is not necessary to prune every tree, prune only the most desirable individuals. Trees with blister rust cankers on the main stem or within 4 inches of the main stem cannot be saved, do not waste your time pruning them. The best silvicultural practice to reduce damage from the white pine weevil is to manage young white pine under an existing overstory. Shade is detrimental to the survival of weevils, it cools the environment and slows diameter growth of the terminals.
Adult weevils tend to avoid laying eggs on shaded white pine with small diameter terminals.
However, heavy shade can be detrimental to white pine growth. There must be a balance between sufficient shade to reduce weevil injury and enough light to maintain adequate tree growth. Most unmanaged stands have a natural crown closure of 70-80 percent. A second important silvicultural practice is to maintain high densities of young white pine until the trees reach about 20 feet in height. This is especially important in open-grown plantations.