Like all other organisms, trees grow and change over time. The tiny seedling you plant today will turn into a lush, vibrant sapling within a year or two. Fast forward a couple of decades, and you’ll see a mature tree; wait a century and you’ll see a towering behemoth, stretching high into the sky.
But this growth and development doesn’t happen in a haphazard fashion. In fact, trees grow in very specific ways. One of the interesting ramifications of this fact is that tree branches do not rise with the tree as it grows. A branch will always be the same height as it was the day it emerged from the trunk as a little bud.
How Do Trees Grow?
To understand how trees grow, let’s first examine the way another type of plant – grass – grows to help illustrate the point.
Grass blades grow from the bottom, near the ground. This means that when you break out the lawnmower and cut the tops of the blades, the biologically important parts of the blades remain unharmed. The blades will grow a little over the course of the next week or two, but if you look closely, you’ll see that the tops of the blades have not changed or grown at all – they’ll still bear the scars of the mower’s blade.
Trees grow in the opposite fashion; they grow from the top. Specialized cells in the ends of each tree shoot (including the primary leader) form areas called meristems. These meristems are the locations from which a tree grows taller and limbs grow longer. If you were to cut a tree like you cut grass, the meristems would be removed and the tree could no longer grow taller/longer.
But because trees grow from their most distal ends, it means that the branches arising from the trunk will never climb higher. If a branch sprouts 3 meters from the ground, it will still be 3 meters from the ground next year.
Note that trees also have another type of meristem, that encircles the trunk and branches and resides beneath the bark. These meristems are responsible for lateral growth (they allow the trunk and branches to increase in diameter).
They May Not Move, But They May Disappear
Just because tree branches do not rise as a tree grows doesn’t mean they will always be there – many trees shed their lowest branches as they grow.
This can occur for a number of different reasons. The tree’s lowest branches are usually its oldest branches, so the lowest branches have been exposed to weather, pests and pathogens for longer than any of the others, which means they’ll likely begin decaying first. Once the branch starts to experience significant decay, the limb is shed to help prevent the decay from spreading into the trunk.
Trees may also shed their lower limbs in response to a reduction in sun exposure. As trees grow taller, they upper branches begin blocking a lot of the sunlight that formerly bathed the lower branches. Unable to maintain photosynthesis, the limb slowly dies and is shed by the tree.
What Can You Do About Low Tree Branches?
While they occasionally make for a good place to hang a swing or bird feeder, low tree branches are often problematic to property owners. They can block entrances, exits or windows; hang precariously over driveways and sidewalks; or provide a conduit for rodents to travel around your property.
Fortunately, skilled arborists can remove the lower branches from many trees — a technique called crown raising. However, great care must be used. Removing a large meter-high branch is a much more significant endeavor than snipping off a tiny branch at the edge of the canopy. Small, young branches are less likely to decay after being pruned than large branches near the bottom of the tree are, so these types of tasks are best left to professional arborists.
If you are experiencing problems with low tree branches, give your friends at Trav’s Tree Service a call. We’ll examine the trees and branches in question and help you determine the best path forward. If removing the limb turns out to be the best option, you can rest assured that your tree will be pruned by skilled professionals, who know how to give your tree the best chance for a long, healthy life.