Winter can be a good time for pruning trees. This has much to do with insects and diseases being dormant at the time due to the cold temperatures. Another reason why it is ideal to prune trees in the winter is because the arborist is able to see what needs to be trimmed due to the leaves being gone. Dead branches or those dying from disease or infestation can be removed so the rest of the tree is saved.
When trees are pruned, low hanging and intrusive branches are removed so that storm damage can be reduced. Minnesota winters are known for large amounts of snow at one time. Trees can break under the weight of the snow and ice. Eliminating weak points can reduce this breakage. If the odds are not reduced, breakage can injure a tree, so this makes proper pruning an important preventative healthcare measure.