Many homeowners may not know that pruning trees in the winter can benefit some trees. Deciduous trees are dormant in winter, so they won’t bleed sap when pruned at this time of year like they will at other times of year. In addition, many varieties of trees are less likely to attract disease or insects if pruned in the winter. Oak trees, for example, emit a strong odor when pruned, and that odor can attract a type of beetle that causes oak wilt. But this type of beetle hibernates in the winter, making this the ideal season to prune oak trees.