Recently I came across the following question: "Is it okay to trim the limbs of a large tree that are touching my roof? Or should I wait until the winter to prune?" When pruning a large tree in your yard, make sure you know a few key points your tree trimmer might not tell you. 1. Never prune more than 25% of your large tree. Older mature trees have less energy stored up to recover from cuts. 2. Wound dressing was once considered a healing agent, but not anymore. If you need it for cosmetic purposes, make it a light coating. 3. You can prune limbs on large trees year round. 4. Never reduce the size of the tree by topping or hat racking the tree. The proper way to prune a tree is by thinning a tree or reduction pruning. Thinning is removal of specific limbs in order to open up foliage of the tree, reduce the weight on heavy limbs while maintaining the beauty of the tree. Reduction method works by pruning back the leaders and branch terminals to a lateral branch assume the role of the new lead branch.