Older Douglas firs don't need much pruning.
Many people plant Douglas firs on their front lawns to be used as outdoor Christmas trees. Although most sources will recommend that you prune your Douglas firs while they are young, it is sometimes necessary to prune back older, larger trees to promote healthy growth and air circulation. Trimming away dead limbs also prevents infections. You should avoid pruning unless your Douglas fir shows signs of poor health or has a lot of dead branches.
Instructions
1. Prune your Douglas firs from mid to late winter. During this time, the trees will be in their dormant stage, which is the optimal time for pruning. By pruning during January and February, you can avoid trimming off any new growth, which can be harmful to your trees. Wear gloves and long sleeved clothing when working with Douglas firs -- their branches and needles can sting a bit.
2. Remove any dead or damaged limbs first. For thin branches that are low to the ground, use pruning shears. For thick branches or anything hard to reach, use a pruning saw. For branches out of reach of your pruning saw, work with a partner and a ladder to get to the topmost limbs.
3. Prune any limbs that cross over each other. This will improve air circulation in the tree and allow more light to shine through the limbs. Use the same technique as you did before. Be sure to work with a partner for higher branches.
4. Shape your Douglas fir. During this stage, be wary of trimming too many branches. Douglas firs really don't need that much pruning, particularly when they are older. Trim only what you need to in order to achieve the desired shape. Traditionally, people shape Douglas firs to look like inverted cones, but feel free to be creative.
