Trees are a major part of our landscape and countryside. They provide much needed shade and greatly increase property values. Trees can reduce your heating and cooling costs for your home. Some trees yield tasty nut and fruit crops. Many wildlife are dependent on trees for food and shelter. The leaf litter in the Fall makes priceless compost and mulch.
When we see something unusual on our trees, it is natural to wonder what is going on and is it harmful.
Let's take a look at some things that can be found on trees that might be a cause for concern at first sight.
Spanish moss Once a significant industry revolved around this dangling bromeliad. Upholstery used to be stuffed with Spanish moss for padding. The moss is still used for crafty projects and to cover the soil of house plants. Birds of course love it for nest lining! Generally considered not to be a threat to a tree, in excess the weight can break down tree limbs. Severe populations of moss can shade lower limbs causing them to become weak. Pest control companies can spray a tree with a copper based compound to kill the moss if needed.
Resurrection fern This attractive, short fern lives on large limbs of oaks, nut trees and other hardwoods. During dry weather it will shrivel up and appear to be dead. With a rainfall event, the fern springs back to life and turns green again. A copper fungicide has been suggested if you want to kill this fern but there is a debate whether this is effective.
Mistletoe The mistletoe is a true parasite of of hardwoods and sucks their sap in order to survive. If there are only a few “bushes” in your tree they can be cut out including at least one foot of the limb, back toward the trunk, they are growing on.
Tent caterpillars You can see the webs of tent caterpillar from a long distance away. They feed on pecans, cherry trees and persimmon trees to name a few. The web protects the “herd” of caterpillars as they eat the foliage from the tree limb inside the web. An insecticide can be used to kill the caterpillars but it helps to disturb and open the web before you spray. Trying to burn the web is a risky business and could start a fire on the ground that can get out of control. I noticed one of my tall black cherry trees had some webbing one year. The next thing I knew a flock of birds were eating lunch, so to speak, up in that tree!
Variable oak leaf caterpillar The “variable” part of the name refers to the tendency of the caterpillars to be of different colors from shades of light green to light brown. They feed on the leaves of oak trees tending to prefer the laurel oak. A heavy infestation of caterpillars can cause the wooded area to have the sound of rain as their droppings fall to the earth below. Insecticide sprays such as Bt can be used if the tree is not too tall to spray. When infestations are heavy, I tend to also find beetles that prey on the caterpillars.
Galls When I first moved to north Florida, I was not familiar with Laurel oaks. I found myself one time under a tree looking up and thought it was a scene from a Halloween movie. The smaller limbs had all these round structures and looked deformed. There are tiny wasps that lay their eggs in the tender twigs of Laurel oaks and other trees. As the insect develops, enzymes are secreted causing a woody protective ball to form around it. The limb generally goes on to live and over the years grows around the gall. Once the insect has laid her eggs it is too late for sprays to prevent the galls
Squirrel nest Hunters and outdoors-men know that a bundle of leaves in the fork of a hardwood limb in the dormant season tends to hint of a squirrel nest. Someone that is not familiar might think this was a deformed growth or disease causing the cluster of leaves. No control measures are needed – just enjoy the frolicking young ones in the Spring as they chase one another around your tree.
Flaking bark I have been asked on more than on occasion why the bark of a tree was flaking. It is possible to have a bacterial infection to develop under a tree's bark causing the bark to fall off in chunks. This is usually associated with a rotten odor and oozing sap. A weak bleach spray can be used but generally this condition has to run its course. Other trees such as Drake elm, shagbark hickory and crape myrtles naturally flake their bark as they grow. For them, there is no cause for alarm.
Africanized bees Although they are still not common in this area, Africanized bees have been seen on occasion. I happened to see a small nest in the Live Oak area several years ago but the nest was abandoned. If you see anything hanging from a tree limb that looks like bees, wasps, hornets or other colonizing insects it is best to keep your distance. Call a pest control company if you believe the colony will be a concern for you or your family.
Wood borers Ambrosia beetles, pine borers, peach tree borers and several other insects can tunnel through wood at some stage in their life cycle. Look for signs of oozing sap or sawdust around the base of the tree. Unfortunately, once in the wood it is difficult to kill these invaders. A wire probe can be used if they are not very deep. Chemical sprays do not penetrate the wood and are typically ineffective. Seriously infested trees such as pines with several borers and generally recommended to be cut down and removed or burned to prevent the spread of the borers to nearby healthy trees. One consolation is that most borers are particular on what type of tree they like. A pine borer for instance will not move over to an oak tree.
Lichens Often seen clinging to the side of a tree or large shrub, lichens are interesting organisms. They are symbiotic organisms in that there is a fungus and an algae living together. The fungus contributes moisture while the algae contributes photosynthesis. They also live on rocks, fence posts, and even on wires and irrigation tubing. They do not hurt your tree but can be unsightly. A copper fungicide will help kill over the course of a few weekly sprays.
Psocids Also known as tree cattle, the psocid insects travel in herds along the tree trunk looking for organic matter to feed on. They do not hurt the tree, but look ominous since they surround the trunk and tree limbs with a white webbing for their protection. They mostly feed on dead bark and lichens.
Most of these situations are not harmful to your trees in the long run even though they look ominous at first sight. Trees are made to be wonderfully resilient. Enjoy the blessings provided by your trees and the beauty of the great outdoors!
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