Western red cedar, Thuja plicata, is an evergreen conifer hardy to USDA Zone 5 Landscapers use it in gardens as a background or shade tree, and it is especially valued for its graceful, drooping branches and reddish bark. Well-adapted to wet soils, it will grow under ordinary garden conditions and even tolerate a bit of drought once established. It may need occasional thinning to allow more light to reach the ground or pruning back from walls and fences if planted without allowance for the length of the curving branches.
Remove any branches touching walls or fences. Either cut back to the main trunk of the tree, using a pruning saw, or to a side shoot, using a lopper or pruning shears. Leave no more than a quarter-inch of stub beyond the growing branch that remains.
Cut away any branches that are producing too much shade. Start from the bottom of the tree and work up the trunk, removing small branches at the trunk and leaving the major framework of the tree.
Prune side branches from the remaining limbs, leaving some green leafy shoots to continue growth.
Cut off some of the smallest branches or twigs, using pruning shears. You can reduce the amount of shade without changing the basic shape of the tree by removing these small bits of growth.