Canadian Forest Service Publications
Releasing unweevilled white pine to ensure first-log quality of final crop. 1979. Stiell, W.M. The Forestry Chronicle 55(4): 142-143.
Issued by: Pacific Forestry Centre
Catalog ID: 4550
A plantation of eastern white pine was established in 1939 on an old field, at the extremely close spacing of 0,66 × 0,66 m in an attempt to limit the occurrence and severity of damage by the white pine weevil. A pre-commercial thinning at age 19 released selected crop trees, unweevilled within the first 5-m log, which have since grown well and should survive to maturity if periodically released. The untreated part of the plantation showed sustained heavy mortality from suppression, drastically reducing the numbers of unweevilled trees which were mostly in the lower crown classes. It was concluded that even a dense stand of white pine will retain only a negligible number of trees without weevil damage to the first log through to the final crop, unless some form of protection is provided, or release thinnings are started at an early age. Plantation establishment at very close spacings is not economic, but early release could be a feasible approach to managing dense natural stands of open-grown white pine.