We have a group of White Pine trees in our back yard. They were planted as a wind break and to screen the view from the electrical substation just across the field. They are huge trees now. Especially beautiful in winter after a snowfall. However, they are also a nuisance when I try to mow the lawn. The lower branches poke me in the eye or smack me in the head. So I decided it was time to trim them off. I double checked with the Master Gardener text and had the extension agent come out to clarify for me. It worked out well since he was a forestry major, trees are his thing.
June through July is the time to trim pine trees. If you are just trimming the tips of the trees keep in mind that some trees don’t produce fruit, pine cones, until they are at least 20 years old. Also note that trimming the tips will cause the apical dominance to be broken resulting in more branches. Which is how those full, bushy Christmas trees are made. If you are trying to maintain a certain shape to your tree you fist need to consider the natural growth habit, the area in which it is planted and the space available. A white pine can grow to be very tall. The tallest accurately measured is the “Boogerman Pine” in the Cataloochee Valley in the Great Smokey Mountains National Park. It stands 188 feet tall, it was measured at 207 feet before losing it’s top in Hurricane Opal in 1995. So do your research before planting a tree that may quickly become too big for your available space.
If you plan to trim off entire branches you want to cut off at the branch bark ridge. This is a picture of the branch bark ridge on one of the pines.
See the bulge from the trunk as the branch grows out? You want to make your cut right against it but not actually into the collar. This will create the smallest wound possible and make it easier for the tree to heal. If it is a larger branch cut a notch into the bottom about 6 inches from the collar. That will allow the branch to bend and not break ripping off a large section of bark with it.
It took me about an hour and a half to trim up the seven trees I have. Now I can walk under them and not be injured. I only trimmed the lowest branches and the dead branches I could reach from the ground. I’m only 5’4″ so, yeah…