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Florida Live Oak

A. S. Jensen

Few native trees are as magnificent, or beautiful as huge old Florida live oaks (Quercus virginiana Mill.). These long-lived, pest-free trees are among our most valuable and historic shade trees. All too often shorter-lived, disease-prone species of oak such as laurel oak (Q. laurifolia Michx.) or water oak (Q. nigra L.) are planted instead of live oak.

Range

Live oak grows in hammocks, bay heads, and lake margins in every Florida county. It is one of the most characteristic of trees of the coastal plain of the southeastern United States. It grows from Virginia to Texas on a wide variety of soils.

A smaller subspecies, sand live oak (Quercus virginiana var. genimata (Small) Sarg.) forms thickets of small trees on sand pine scrub and is the common live oak of deep sandy soils in general. It is often confused with true live oak. Sand live oak, however, usually bears acorns in clusters of two and the boat-shaped leaves are more heavily veined than regular live oak.

Description

Most Floridians recognize a live oak, especially a large one. Specimens may be 20-30 feet in circumference and have a branch spread of over 150 feet. Usually their greatest height is only 40-50 feet. However in bay heads and hardwood hammocks under crowded conditions, they often develop huge branch-free trunks that over-top all other native hammock vegetation.

Gray-brownish bark, broken into uniform, narrow flat-topped ridges, is characteristic of live oak. Leaves are dark green and shiny above, paler and downy below. The fruit (acorns) mature in one year and are often sweet and edible. Wildlife of all kinds relish live oak acorns.

A broad spreading crown, evenly corragated bark, revolute leaves and nearly black acorns in top-shaped cups are distinguishing characteristics (Figure 1).

Flowering and Acorn Production

In late January or February live oaks shed their leaves as new leaves mature, and they produce many flowers every spring in March or April. This "leaf-fall in Spring" often causes concern among live oak watchers not familiar with the habits of evergreen oaks. Acorns mature in September or October of each year. Acorns average 390 per pound. They germinate soon after falling unless acorn weevils invade them.

Vegetative Reproduction

Live oak sprouts from both root collar and from shallow roots. When a tree is cut every root may send up three or four sprouts. When sprouts are mowed, new ones appear in even greater numbers. This makes unwanted live oaks difficult to kill.

A majority of historic trees in the southeast are probably live oaks and great age is usually attached to these huge old live oaks. Probably the largest live oaks are not over 200-300 years of age and most are younger. Frequently sprouts or groups of several trees grow together to form huge low-branching specimens. Louisiana's Live Oak Society will not accept a tree as being one hundred years old unless it is 17 feet in circumference (a growth rate of over two inches in circumference per year). In Florida's sandy soil, a growthrate of one to one and a half inches per year circumference is not uncommon. However, tree growth varies greatly with location and growing conditions.

Care of Live Oaks

All trees respond to proper care and live oaks are no exception. Trees may be grown from seed or transplanted easily from the woods. Bare rooted live oaks with a trunk diameter of several inches (as large a tree as you can carry on your back) transplant well if root-pruned and top pruned. Keep them well-watered for several months after transplanting. Don't plant them too close together--in 100 years one live oak may cover your Whole lot!

Live oaks benefit when the lawn is fertilized. However, special treatment may be given them by punching holes two feet apart under the tree canopy and beyond the drip line. From two to four pounds of complete fertilizer per inch of trunk diarneter may be applied in these holes and watered in well. Remember not to apply commercial fertilizer closer than one foot to the tree trunk to prevent root collar injury. Example: A 3-foot-diameter live oak (36 " ) could have 72-144 lbs. of fertilizer spread under it. Your county agent or urban forester can provide you with on-the-ground advice. Spanish moss and resurrection fems that often grow on live oak branches are not harmful and are loved by some people but disliked by others. These three plants have historically grown together in harmony.

Uses

Today the major use of live oak is as a shade tree. In former days it was a vital part of wooden ship construction. Ship knees, timbers, and planking of live oak brought a good price and it is said that by 1832, almost all merchantable live oak within hauling distance (2 or 3 miles of a navigatible stream) had been cut to build ships.