If you must thin during these months, treat the cut stumps with boron immediately after felling. If the stand is already infected, thin frequently to salvage the infected timber. In periods of low beetle infestation, thinning can be scheduled for any time of the year. Where beetle outbreaks have been moderate, observe caution. Do not thin between the months of March and October during periods of moderate infestation.
Winter thinning minimizes the risk of beetle infestation.
When a high number of beetle attacks have been observed, do not thin your timber. Harvesting damage to residual trees after a thinning often attracts the beetles and can lead to the destruction of the stand. Studies show that thinning reduces the risk that a stand will be infested with beetles. However, you must be sure that the thinning operation is timed properly and produces little residual tree damage. Many landowners work with consultants to thin their timber.