Tag Archives: Pruning

Arborheroes

Tree Watchers Chuck Young, Chad Altemose, and Jim Abbot were at work pruning oak trees in our parks on Saturday, November 20. Next time you’re walking by or through Delta Park, Triangle Park, or Springvale Park, you may have the feeling that they seem more . . . capacious. That’s because we raised the green “ceiling” by removing or sometimes shortening lower branches on several oaks.

Chuck Young
Chad Altemose

About Tipping

No, not that kind of tipping.

I’m talking about snipping off the ends of tree branches to shorten them.

In the drawing, the blue line indicates roughly where someone snipped off the ends of branches a, b, c, and d. You can see how the tree responded: a spray of profuse new growth (“shoots” or “water sprouts”) from near the ends of the tipped branches.

Why?

At the tip of a tree branch there is a so-called terminal or apical bud. This specialized bud regulates growth of the entire branch. (After all, the tree needs to grow up and out to reach that all-important sunlight!)

A hormone is involved, called auxin. Think of auxin as being like a sleep potion. All those many other buds lying under the bark along each branch? Auxin keeps those buds dormant.

But if I snip off the terminal bud, some of those dormant buds along the branch “wake up.” They send out shoots which will become twigs which will become new branches.

Tipping a branch to clear a sidewalk or street is usually counterproductive. Within a year or two, the problem will be twice or three times as bad. Look how many sprouts were growing on this tipped Bradford pear. (Located on Austin Avenue at its intersection with Euclid. Thanks to Meghan for identifying this hazard to pedestrians.)

Instead, always cut a branch just beyond a node. A node is simply where a leaf, twig, or secondary branch attaches to a larger part of the tree.

Put differently, your goal is always to leave a bud which can become the new terminal or apical bud of that branch, controlling that essential hormone auxin, so that the tree can grow up and out.

Repair work:

TELL US WHERE TO WORK

From now until at least May 2022, Inman Park volunteers will gather on the third Saturday of each month to

  • prune branches that are growing into the sidewalk or street,
  • remove vines strangling trees in our parks and greenspaces,
  • cut out or pull up invasive plants that crowd out our native species.

You can help by telling us where you have noticed that a sidewalk is obstructed or a park space is being overtaken by vines.

Leave a comment on this post with your suggestions, and thanks for the help!

Bark Inclusion

If you happen to be a tree, one of the bigger challenges you have is this: I need energy to grow and reproduce! So I’m gonna reach for sunlight, water, and nutrients. But how far and fast can I reach before something like this happens?

The photograph above shows an American elm (Ulmus americana ‘Princeton’) planted years ago by Tree Watch and Trees Atlanta in Freedom Park.

American elm is really great at reaching. It can grow fast. When it’s at home — ‘home’ being rich, alluvial soil in a forested floodplain along a river or stream — a tall American elm will have channeled so much of its energy into growing upward, in order to reach that lovely sunlight at the top of the forest, that it may have no branches at all until the 50- or 60-foot mark.

Photo credit: Christian O. Marks

Of course, an American elm growing in an open, grassy section of Freedom Park has no difficulty at all accessing sunlight. It’s like a kid left alone in a candy shop. (Think of that poor elm tree in Freedom Park as a kid with a terrible tummy ache.)

Continue reading Bark Inclusion