Do you love your trees? Then Don’t Do These Five Things!

Trees. They are fundamental to our homes, to our planet, to our very lives. We watch our kids grow up on tree swings and play make believe in tree forts. We shake out our picnic blankets in their shade on warm summer days. We thank our lucky stars that a tree provides the house some shade in the hottest days of August. And yet somehow, we still as a whole do not understand these gentle giants and the best practices around their upkeep. As someone who spent three years as an arborist, climbing, pruning, cabling, planting, removing, and just loving trees, these are the top five practices I see around town that make my blood boil. Please read this list and do not let a tree care company (or yourself) commit these acts!

1. Cutting Into The Branch Collar

When it comes to tree care companies, unfortunately they are not all operating at the same standard. If you care about your trees, you need to do the research to find someone you trust. Looking for an ISA certified arborist is a good place to start, but also ask around. Your AG gardeners definitely have an opinion; I myself am one of them. If possible, have the company prune a trial tree so you can see how they work. Tree care can be expensive, but a good arborist makes the difference between a healthy tree that will be on your property for generations versus one that gets hacked at and becomes a hazard. 

The top thing on my list that everyone should look out for is improper pruning techniques. To understand, we need to talk briefly about tree biology. When a branch is pruned, it will create a wound that the tree must then expend some energy to heal and defend from pests and disease. [[[At the base of a branch, where it connects to the trunk or stem, is the branch union. A swollen collar develops here called the branch collar, which is where important hormones are stored to help the tree properly recover from a cut.  Arborists use the branch collar as a guide to know where to cut. By cutting just beyond the branch collar and at the proper angle, it ensures that the branch protection zone is not compromised which enables the tree to slow and block the spread of decay organisms into the trunk while it is trying to heal. I cannot stress enough how critical this is to the long term health of the tree. Cutting a large branch flush to the trunk or with a tear will allow decay to set into the trunk of your tree.

2. Topping

Do not top your trees! Just say no! 

Topping refers to the removal of the central leader in order to reduce the height and or spread of a tree. This is considered an unacceptable practice by the International Society of Arboriculture (ISA; the organization that certifies arborists). When you remove the tops of trees, you are essentially starving the tree. It reduces the tree’s ability to make the energy needed to heal from pruning cuts and it removes the energy that was stored in those upper branches. These large cuts then have a difficult time forming woundwood which then leaves them vulnerable to insects trying to invade and the spores of wood-decaying organisms such as fungi. 

Ironically, when a tree is topped for height reduction, it is a very temporary fix. The tree will put on rapid new growth in the form of sprouts (watersprouts). These are typically numerous and leggy, so the tree will actually have a denser crown than it did before. Furthermore, all of those new branches have a much weaker attachment which means the tree is now more of a hazard. Lastly, not every tree can handle this extreme pruning style. It may only hold on for a couple years before declining and eventually dying.

3. Covering a Wound with Dressings

While we are on the topic of pruning, I want to talk about wound dressings. These are compounds (such as tree paint) applied to pruning cuts primarily for cosmetic purposes. Most research has shown that these are not needed. Unfortunately, they can actually impede the healing process by locking in moisture to the cut and inviting decay. Trees may not be able to heal damaged tissue like we can, but they have evolved to compartmentalize wounds so that the damage does not spread any further. In the same vein, you should not attempt to fill in large cracks or holes in trees with cement, foam, or any other foreign substance.

Double Ouch! Bad cut and unneeded wound dressing.

4. Planting a Tree Too High or Too Low

Planting a new tree? How exciting!! Do it correctly so you can enjoy the tree for its intended life span. Nothing makes me grumble more when I’m driving around town and I see baby trees planted too low with giant volcanoes of mulch around them. I think people have seen this done so much that we think that is the proper way to plant a tree. It is not. 

When a young tree comes from a nursery, it is common that there will be too much soil around the trunk. Once removed from its container or ball-and-burlap, you must locate the trunk flare, or where the trunk gets wider indicating its primary structural roots, by gently removing soil from the top. Do not remove all of the soil from the root ball as that would stress the tree. Once you have located the flare, you can then determine how deep to dig your hole. The planting hole should never be deeper than the trunk flare to the bottom of the root ball. It is better to have a wider, saucer shaped hole, as most of the root growth occurs near the surface. Furthermore, if a tree is planted too deeply, it can stress, drown, and suffocate the roots. If the soil drains poorly (like clay), then the tree should be planted slightly above the soil grade. A quick note on mulch: it should never touch the trunk of the tree. This can lead to bacterial or fungal infections. It certainly shouldn't be in a giant volcano around the tree. I think the thought here might be to help trap water for the tree, but it actually reduces oxygen and water availability to the roots. It would be better to do a broader mulch circle.

Notice how much soil had to be removed from the trunk to find the flare.

5. Not Checking For Girdling Roots When Planting

Nothing makes me more sad than to see a ten to fifteen year old tree declining well before its time just to find a massive girdling root at its base. This is something that could have easily been avoided if it was just planted properly. Another reason it is critical to find the trunk flare when planting a young tree is to locate and remove circling roots. By gently probing and locating the primary roots, you can find any circling roots and remove them before they grow into a girdling root. These roots, if left to grow around primary roots, choke off vascular tissues which can lead to the decline and death of branches or even the entire tree.

See the root horizontal to the ground “choking” the trunk and other roots? This is an example of a girdling root.

I hope you find these tips helpful! Let's all help our wonderful trees live long and happy lives.

-Lauren Saurs