Tree Myths Part Two

Danny Lauderdale, Horticulture Agent North Carolina Cooperative Extension Pitt County

Last week I began a review of tree myths and ran out of space. Let’s continue the review.

Myth #8:
Pruning is only for large trees. It is easier to prune trees when they are small versus waiting until they are large to correct problems. Most trees should have one main trunk. If you’re not pruning, you should remove competing main trunks at planting. Pruning at a young age should remove lower limbs for ease of maintenance.

Myth #9:
Trees have deep root systems. Most tree roots are in the top 6 to 24 inches of soil. Fine feeder roots are closer to the surface and large structural roots are deeper. Soil compaction and poor drainage are usually the limiting factor for root depth. Most tree root systems are like a pancake instead of a carrot or a mirror image of the canopy. Tree roots spread at least 2 to 3 times as far as the branches spread.

Myth #10:
Tree wounds should be painted or sealed. Paint or tree wound sealants only make us feel good. They do not stop wood rot, they seal in moisture, they prevent wound wood from forming, and they prevent trees from closing off damage.

Myth #11:
Tree wounds heal. Trees compartmentalize wounds or decay. They plug their own vessels on the back and sides of wounds to close them off and new wood that grows begins to close them on the front side. They do not heal and go away but they are encased in old and new wood.

Myth #12:
Topping makes trees safer. Topping is the indiscriminant cutting of tree branches back a certain distance without regard for tree anatomy or proper structure. The thought is to take weight off the top of the tree so it does not blow over. The reality is that the tree branches that regrow are weakly attached and the result is branches that begin falling out of the tree once they get 4 inches in diameter or larger. The large cuts left by topping also rarely close and result in decay at the end of the branches that are left. Topping, by removing much of the leaf growth, also reduces shading in the canopy which results in sunscald damage on thin barked species.

Myth #13:
Lichens damage trees. First what are lichens? They are a fungus and algae that work together. They often grow on tree bark, rocks, fences, compacted soil and many other surfaces that sit still long enough. They often look scaly or feathery in appearance and may be brown, green, or gray in color. They are not feeding on plants but make their own food through the algae. We often see more of them on weakened trees simply because they are slow growing and there is often more sunlight reaching the bark on those trees.

Myth #14:
Tree roots growing on the surface should be cut or covered over with soil. Every root a tree has is valuable to the tree for structural stability and supply of water and nutrients. Cutting tree roots can result in an unstable tree. Covering tree roots with soil can smother young feeder roots and weaken trees. You can place 2-4 inches of mulch over surface roots but keep it away from the trunk.

Myth #15:
A tree that drops a large branch needs to be cut down. There are many reasons why trees loose branches. Wind damage may split them, shade by cause a lower branch to die, or improper pruning may have resulted in a weakened area. Some tree species like pines naturally loose lower branches to shading. As trees age they need to be evaluated for proper structure, weak areas, or storm damage. Certified arborists are best employed to evaluate the condition of large trees and recommend maintenance required.

Myth #16:
Trees damage sidewalks, curbs, and streets. I like to say that trees just try to survive. We often plant them in bad situation where trees should not do well. Many times they struggle and die. Sometimes they overcome the situation and thrive, sending roots wherever they can to grow. As the roots and trunks grow they often come in contact with infrastructure (pipes, lines, concrete, and asphalt). If we want to keep that infrastructure intact then we need to plan for the growth of trees including designing, engineering, constructing, and planting properly so there is as little conflict between trees and infrastructure as possible.

If you are interested in learning more about trees and helping out the community, I encourage you to participate in Greenville Community Tree Day on Saturday, November 8. The event is sponsored by ReLeaf and the City of Greenville. You can learn more about ReLeaf and the Community Tree Day by visiting www.releaf.us. If you have gardening questions contact the Pitt County Master Gardeners at 252-902-1705 or pittcomgv@hotmail.com.