Remove damaged and dead branches. Remove diseased branches by making thinning cuts bellow the diseased area. Never prune the trunk. This results in the growth of multiple weaker leaders prone to snow and wind damage. If multiple trunks of equal size develop, select one as the leader and cut off the rest. Evergreen trees are low-maintenance and mostly require corrective pruning.
Allow evergreen trees to grow in their natural shape. Pruning evergreens promotes fuller growth but it is ineffective for size and shape control.
To remove large branches without injuring the tree, make an undercut one-third or halfway into the branch, 12 to 15 inches from the trunk. Make a second cut on the top side of the branch 2 inches above the previous cut and remove the branch. Make a third cut outside the branch collar to remove the remaining branch.
Most spruce, fir and Douglas fir trees tolerate pruning that doesn't involve cutting back past the needles. If a branch's size is too disruptive, cut back the branch all the way to the trunk. Dwarf Alberta spruce, blue nest spruce and bird’s nest spruce don't tolerate pruning.
Adult pines don't tolerate extensive pruning. Young pines tolerate mild pruning to promote fuller growth. Don't use cutting tools. Instead, snap off one-third of the growth when the needles are in a cluster.
Junipers and arborvitae trees can be pruned all year long except for winter. Prune by cutting exterior branches back to upward-growing branches.
Pruning past the needles causes the tree to have permanent bare spots. Regular shearing creates excessive exterior growth that shades the interior, thinning out the trunk and branches. Shearing also makes the tree susceptible to the weather and kills exterior needles.
Junipers and arborvitae trees grown in shade are intolerant to pruning.