The Willows Neighborhood Association

Live Oaks - Pride of the Hill Country

So What Is a Live Oak?

The live oak is a memorable symbol of the American South. With its massive trunk and vastly spreading limbs, this long-lived oak is at home in the South, ranging from the Carolinas to Texas.

Live oak is a long-lived, massive, evergreen Southern shade tree. It reaches 40 to 80 feet tall and 60 to 100 feet wide. Its horizontal branches form a broad, rounded canopy. The strong, dense wood of this magnificent tree once made it the choice for many a ship's hull, ("Old Ironsides," had its hull made of Georgia live oak) though today the live oak finds a cherished place as a Southern street and shade tree.

It ranks as the heaviest native hardwood, weighing 55 pounds per cubic foot when air dry. This weight (density of mass) makes the live oak the premier fuel wood.

You can distinguish a Live Oak from other oaks because they do not drop their leaves in winter. Instead, they shed leaves in early spring just as new growth is emerging.

A mature oak tree can draw up to 50 or more gallons of water per day. Trees take up water through their root system. Some of the water evaporates from the leaves in a process called transpiration.

Oak Wilt Primer

Live Oaks can get Oak Wilt by way of root transmission from another Live Oak, or from the sap feeding, Nitidulide beetle. This insect would first have to have fed from a tree with an infected fungal mat. A fungal spore can stick to its body, then be carried to the next tree that the insect feeds upon. Red Oaks are the most common tree to produce this infected fungal mat.

Oak wilt is easy to prevent and difficult to treat. Because the disease travels through the interconnected roots of live oaks at 100 feet per year once the infection is in a neighborhood, you must trench a break in the roots around the infected trees (plus 100 feet). Trenching is disruptive, expensive, and difficult in an urban neighborhood.

Individual trees can be protected with the chemical Alamo injected by a trained applicator but it is also expensive (approximately $30 per inch of diameter). It protects the tree from infection but does not stop the spread of the disease or cure the infected tree.

It's best to avoid pruning live oaks from February through June when the
Nitidulide beetle is active.

Prevent the diseases spread by painting all wounds on live oaks and red oaks. Keep a spray can of pruning paint in your garage to immediately paint any wound on your trees. Every minute you wait after the wound occurs increases the chance of infection. The first two days are most critical. Pruning, weed-eater and machinery cuts on the trunk and exposed roots are especially susceptible to infection.

There are no windows of safety for not using pruning paint because of cold weather or hot weather. Central Texas weather is too unpredictable and changeable--paint every wound all year long.

Firewood from red oaks can also rarely be a source of the oak wilt infection. Protect your neighborhood by managing firewood to avoid infection. It is not necessary to reduce the use of the fireplace in order to stop the spread of oak wilt. Smoke from infected wood burning is NOT a threat! The fungus is destroyed by heat and will not even survive in dry firewood. If you utilize red oak firewood, try to purchase wood from trees that have not been infected or killed from oak wilt. Only wood that has been cured for an entire summer should be stored in the vicinity of uninfected red or live oaks. If you bought oak firewood for the winter and are unsure of its age or origins, use it up before spring.

How to Determine Age of Your Oak Tree

To figure the approximate age of a tree, measure its girth four feet from the ground, convert that measurement to inches and divide by 1.5. An oak will add an average of 1.5 inches to its girth each year, although the older ones grow at a considerably lesser rate.

Links to Informative Sites on Oak Trees

Oak Wilt Maintenance