Hard Mast Management

Guest Post by Derek S. Dougherty

Dougherty & Dougherty Forestry Services, Inc.
PO Box 82013
Athens, GA 30608
Phone: 1-888-285-0947

This article first appeared on the Quality Deer Management Association website.  Reposted with permission from both author and QDMA.  QDMA masthead reads, 

"Ensuring the future of white-tailed deer, wildlife habitat & our hunting heritage. 1.800.209.DEER"

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All experienced whitetail hunters realize that oak acorns are an important food source. Most also know there are two main types of oaks — red oaks and white oaks. While white oaks often get more attention because they are generally more preferred by deer, red oaks are equally important because of their more consistent annual yields. For these reasons, land managers often leave both groups of oaks during timber harvests and even plant supplemental oaks. This is often the extent of a hunter’s or landowner’s knowledge about oaks and their management.

But, much more can be done to manage this important food group and it can be profitable as well. Quality oak timber, especially high-grade red oak, brings a premium price. As supplies of oak sawtimber dwindle, prices are likely to increase even more. Many sites that produce quality oaks can produce quality pines as well. This, combined with the higher internal rates of return for pine plantations, have caused many landowners to convert hardwood stands to pine plantations. With the potential for increasing hardwood prices and the increasing interest by landowners in maximizing acorn production for wildlife, we can financially justify growing quality oak timber.

To produce oak mast and lumber profitably, land managers must understand several factors that affect timber quality and mast production. Because there are so many different species of oaks, I’ll stick to the basics, beginning with the differences between red and white oaks.

On an upland site in North Carolina, you may encounter scarlet oak, water oak, northern red oak, black oak, and southern red oak. All are red oaks, but of these, northern red oak generally produces the highest quality lumber and highest stumpage price. Water oak, on the other hand, generally produces the poorest timber and lowest prices of this group. In the bottomland hardwood areas of Georgia, we may find cherrybark oak, willow oak, water oak, and shumard oak, among others. Again, all are red oaks, but cherrybark oak usually produces the best lumber and prices.

For the white oaks, throughout much of the U.S. we find white oak, post oak, and chestnut oak on the uplands and swamp chestnut, white oak, bur oak, and overcup oak in the bottomlands. While the major difference between white and red oaks is the vessel structure inside the tree, a simplified way to identify these groups is to look at the leaf tips or lobes. With a few exceptions, red oak leaves are pointed and white oak leaves are rounded.

In this article, we won’t provide exhaustive descriptions and characteristics for all the oak species. For an overview, readers may want to refer to the article, Mast Trees-The Permanent Food Plot, by Bassett and Whatley, published in the December 2002 issue of Wildlife Trends. Landowners and hunters should also purchase an informative tree identification book for their area. These references will describe the range, leaf characteristics, acorn size, acorn drop timing and persistence, and other?key characteristics.

Like pine timber, there are many uses for oak timber. Small diameter oak trees can be used for pulpwood production. Medium sized trees can be used to make pallets. Larger trees are used for sawtimber and are much more valuable. Some sawlogs are worth much more than others, depending on the grade of lumber they are capable of producing.

The North Carolina piedmont produces some of the country’s best oak timber. Stephen Henderson, the head procurement forester for McDowell Lumber Company in Asheboro, North Carolina, purchases a large volume of quality hardwood annually. Stephen described oak grades this way:

“In our area, we basically have four grades of sawlogs,” Stephen said. “The most desirable is ‘Prime.’ An oak tree needs to have a dbh (diameter at breast height), 4 1/2 feet above the ground) measurement of at least 20 inches to be prime. More importantly, a prime log must be 100 percent clear (containing no limbs or limb scars) on all faces. Next, No. 1 logs must have a dbh of at least 17 inches and be 75 percent clear. Finally, No. 2s and No. 3s must have a dbh of 13 inches and have at least 50 percent and 25 percent clear wood, respectively. The value increases substantially as the grade improves. Currently, No. 2 grade logs are worth about 200 percent more than No. 3 grade logs. No. 1 grade logs are worth about 33 percent more than No. 2, and prime grade timber is worth about 50 percent more than No. 1. For example, while timber prices differ greatly by region, species, markets, and logging costs, prime red oak logs delivered to our mill today bring about $850 per mbf (thousand board feet) Doyle scale, compared to low-grade logs which bring around $200 per mbf.”

If we are growing oak timber for profit, we should attempt to produce the highest grade lumber possible. So, which sites produce the best oak and which species produce the best grade sawlogs?

“Site productivity depends primarily on slope position and aspect,” Henderson said. “The best upland soils for quality hardwood growth are usually found on north and west facing slopes. As for the red oaks, on uplands in our area northern red oak is the preferred species. Good southern red oak is second, probably followed by willow and then scarlet oak. On bottomlands, cherrybark oak is preferred, followed by willow oak. Of the white oaks, true white oak is preferred on the uplands and swamp white oak and swamp chestnut oak are preferred in the bottomlands.”

We have preferred oaks for lumber, but what about for deer forage? There are certain acorns that deer prefer, but a diversity of oak species ensures reliability and availability over the longest period. White oaks, for instance, often drop around September and are a preferred early fall forage, when they bear. Some red oaks drop a month or so later, in November and December, when acorns can compromise up to 75 percent of a deer’s diet. Some of the smaller acorns, like water oak, willow oak, and southern red oak, even persist later into the winter. Thus, diversity is the key. For timber production, a mix also is generally recommended.

(Editors note: Oak trees that drop their leaves first and then drop heavy crops of small acorns into those leaves are desirable from a wildlife standpoint.  Deer, turkeys and squirrels cannot efficiently mop up all of the acorns.  Wildlife keeps coming back to that stand of trees because they can always find some acorns if they hunt around enough.  Smaller acorns are also attractive to a wider range of wildlife....including ducks.)

“The ideal scenario is to manage for both red and white oaks,” Henderson said. “Red oaks mature faster, but white oaks may live twice as long. With a good mix, you could remove the red oaks first and leave the white oaks for a subsequent harvest.”

Knowing that a mixed oak stand is desirable, how do we get one? This can be especially tricky when existing hardwood stands are dominated by less desirable species like sweetgum, sycamore, maple, hickory, and poplar. Let’s look briefly at three primary ways we can produce an oak dominated stand: (1) we can work with existing, intermediate-aged mixed hardwood stands, (2) we can establish an oak plantation, or (3) we can regenerate a hardwood stand naturally.

“The best option economically is to work with intermediate stands and precommercially or commercially thin them at ages 15 to 25, leaving ‘crop’ trees of the best quality and preferred species,” Henderson said. “If you have a timber stand with a good component of oaks, identify them and then remove the competing species.”

A simple way to do this is by cutting down every tree touching the ‘crop’ tree’s crown. Following the thinning, leave the trees to grow until the next planned select-cut or clearcut harvest.”

But what if you don’t have an existing intermediate-aged stand with a good component of preferred species? Instead, you have an old field or cutover. While it’s not easy or cheap, you can establish an oak plantation from scratch. As with pine plantations, you will need to control competition from weeds, shrubs, and other trees. However, there are substantial limitations when compared to pine plantation management. The use of selective herbicides is limited because hardwoods are very sensitive to many commonly used herbicides.

Because of the complexities associated with large scale hardwood plantings, landowners should seek professional advice and assistance. However, I will provide some basic guidelines here:
(1) Match the oak species to the site. Research the characteristics (e.g., drainage and nutritional needs) of the species you are considering planting and make sure the site is suitable.
(2) Use quality planting stock. Without good stock, survival problems are likely. Most state forest service nurseries provide bare-root stock. Some private nurseries, like International Forest Company (www.interforestry.com or 800-633-4506) in Moultrie, Georgia, even provide improved containerized stock. The Forest Landowner’s Association publishes an annual directory of hardwood seedling nurseries. For more information about?quality oak seedlings, contact the US Forest Service in Athens, Georgia (706-559-4288) and review the extensive research completed on the subject by Paul Kormanick.
(3) Control the competition. In many areas, this is done mechanically. There are some chemical herbicide options now available which may be cheaper or less intensive. Contact your local herbicide sales representative for options.

If you are really interested in converting a cutover to an oak plantation, consider contacting the North Carolina State University Hardwood Cooperative (919-515-2891) for results from their chemical site preparation studies. For herbaceous competition, you may need to selectively spray a non-selective herbicide such as glyphosate, making sure not to contact the oak foliage. Multiple herbaceous weed control treatments may be beneficial during the first and second growing seasons. Again, check with your local herbicide sales representative for recommendations and product label specifications.

Establishing oak plantations can be expensive. But what about regenerating oak stands naturally? While this is a good option in some areas, it too has obstacles to overcome. The main obstacle is that most oaks are considered “climax” species, or those that grow slowly but are long lived and dominate when the forest matures. Thus, after a timber harvest, faster growing species like poplar, sweetgum, sycamore, and maple will overtake the site and shade out a large percentage of the oaks.

In Piedmont hardwood areas, silviculturists use a couple of methods to favor oaks. First, they may leave enough mature, acorn-bearing oaks (15-30 per acre) during the timber harvest to provide a “shelterwood” effect. The shade from the residual trees deters the growth of the light-loving species and encourages the young oak sprouts. The residual trees are later removed (3 to 5 years) after the young oaks get established.

Another method is to control the competition with hot controlled burns. The fire will also burn the oaks, but the oaks, with a larger root system and adequate reserves, may resprout more vigorously than their competitors after the fire. For more detailed information about this technique, refer to an article by David Van Lear in the May-June 1999 issue of Tree Farmer.

One final suggestion would be a hybrid of the two techniques outlined above. After letting your stand resprout naturally following a clearcut or shelterwood harvest, use a foliar herbicide to treat the undesirable species and then plant bare-root or containerized oaks in the competitor’s place.

In summary, if you want to maximize the wildlife or timber value from your oaks, you should incorporate some of these advanced oak management techniques into your management plan. If your knowledge about the subject is limited, you are not alone. Fortunately, quality information and expertise is readily available.

Contact a professional forestry consultant, state forestry school, the U.S. Forest Service, a chemical herbicide sales representative, or even the nearby grade hardwood mill owner for advice. Then, put your new knowledge to work. It will be worthwhile financially and recreationally. In the years that follow, your family and friends will look forward with great anticipation to spending another successful opening day on the productive oak ridge you have improved or established.

About the author:
Derek Dougherty received his BS in Forest Resources, Forest Business from The University of Georgia and is president of Dougherty & Dougherty Forestry Services, Inc., in Aberdeen, North Carolina and president of Progressive Timberland Management, Inc., in Macon, Georgia.