Life on an Oak Tree

Do you ever think about all the life going on around you- on plants, in the water and soil or whatever? Sometimes we just need to take a little time to stop and smell the roses ( I used to smell them as I ran by ) or spend some time looking a little closer at the world around us. It can certainly be eye- opening.

One of my favorite things to do is to take a lightweight three- legged folding stool out on hikes and sit down for a while in areas that show a promise of something good to come if I can simply wait a bit. It is always a surprise to discover all the activity going on that I would have missed because of a failure to employ the railroad method of outdoor walking: ‘ stop, look and listen “..  So over the years I have learned to heed the words of Paul Simon- “ slow down, you move too fast… “

Today my co-worker and I stopped to admire an oak and it became apparent that there was a lot of activity on its lower branches. Holes from feeding insects, leaf shelters and galls were just a few things we noticed. But a closer look proved that we had just seen the tip of the iceberg. Tiny creatures were crawling along twigs and leaf undersides that turned out to be yellow nymphs of some sort of tree hopper insect. And dangling down from the tree on silken threads were several tiny instars of Ashen Pinion caterpillars and some other, as yet unidentified, caterpillars. There were also two tiny gypsy moth caterpillars just beginning to show the definitive dots that run along their back.

Early in the spring when oaks are just beginning to break bud, catbirds normally are back. And as leaves begin to unfurl, look and listen for Scarlet Tanagers and Baltimore Orioles in the top of the canopy of mature oaks. There must be caterpillars there because you will see them poking around and under the newly opened leaves. This year there were an abundant amount of  male Red- bellied Woodpeckers advertising the fact that they thought they had constructed a fine nesting cavity suitable for any females  in the area. The males can be hard to spot because they sit inside their hole and poke only their head out and sing sporadically all day. Because of past storms, many oaks have dead vertical limbs that are just what red- bellies like for drumming and excavating.

Oaks have the distinction of being the host for many gall insects. While most are not a threat to the health of the tree, they can occur in large numbers on certain trees in  some years. One of the most common galls familiar to many people are those formed by the oak apple gall wasp. These are large and are a smooth with a  limey green color. Neatly tucked inside is the larva of the wasp, safe and sound from predators and with a good supply of food supplied by the oak’s abnormal growth caused by the trees response to chemicals the female wasp injected with her egg. There are other galls also, including “ potato “ and “ bullet “galls on twigs stems and rosette galls on leaves.

 

Oaks are also the host plant for over 500 species of caterpillars, which makes them the champ when it comes to supplying bird food in Connecticut. Right now you may see Ashen Pinions ballooning down on silken threads. Or flip leaves and look for tiny Gypsy Moth Caterpillars- only about an inch long right now. Many caterpillars form leaf shelters, or tents, where they hide during the day. Go out at night with a flashlight and look for these guys. Right now there are many sallows and pinions, but later in the summer the daggers and prominents abound, and I find these caterpillars a more exciting find. They are bigger and more interesting in shape and color, as well as sometimes having warty protuberances sporting long hairs. Most of these can be found either along leaf edges of on leaf undersides. Look for feeding damage and check out nearby leaves.

A little insect that may be overlooked is the acorn weevil. This  insect lays its eggs inside acorns by chewing out a hole with its mouth and inserting one egg inside the developing fruit. Look for acorns in the fall that have a small round hole. This is evidence that the larva that was feeding inside has pupated and exited as an adult by chewing its way out. Sometimes squirrels can be seen turning acorns around in their paws as they look for these holes, or feel the weight of the acorn. They will not waste valuable time opening an acorn that will not supply a sufficient supply of food.

 

A few years ago, there were lacewing eggs everywhere on the undersides of all kinds of oaks. The next year- hardly any on oak, but there were a lot on cherries. Several years ago there was a hard frost when oaks were flowering and that fall there were few, if any, acorns. Squirrel and chipmunk population were noticeably down the next year, perhaps because of a lack of food for the winter. Deer and turkeys also rely on acorns for food during the fall and winter. Sometimes you can see the places under oaks where deer have pawed aside the snow looking for any acorns that may be left.

So next time you see an oak, imagine all that is going on in, around and on that tree. And maybe look a little closer to discover a little of what that tree has going on. And enjoy its shade!

Pamm Cooper