Growing Hardwoods

Managing your trees

After trees have been planted there are a few management techniques that will ensure the most productive and healthy crop. With some regular management you can help your trees stay free of competition and maximize their growth potential. The descriptions below can provide information on each technique. For further information, Planting and Care of Fine Hardwood Seedlings is a series of 20+ guides developed by the Hardwood Tree Improvement & Regeneration Center.

Deer Control

Managing deer damage is important to allow newly planted seedlings to get above the browse line. If deer damage is a serious problem, you may need to install fencing or consider deer repellents in the short run. Deer populations can also be managed through hunting. Taking does is critical to control the herd size.
Illinois study comparing deer repellent products (Illinois Walnut Council)
Comparison of Commercial Deer Repellents (USDA APHIS, July 2001)

Weed Control

Weeds affect black walnut trees the same way they affect other crops. They rob them of moisture, nutrients, and light. But walnut growers can use a variety of mechanical and chemical methods to protect their trees from weeds. More...

Ground Cover Management

The ideal ground cover in a black walnut plantation would be similar to that in a dense mature forest or mixed black walnut stand. Unfortunately, when a plantation is established, regardless of the type of site preparation, the walnut seedlings will not be tall or dense enough to shade out the vegetation that competes against them. More...


Fertilization is perhaps the least understood of all the cultural practices associated with managing black walnut trees. Many fertilization studies have been done, but the results have been inconsistent and hard to compare. Don't fertilize walnut trees on good sites, it doesn't seem to help the trees grow; but it does help weeds grow, which then suppress walnut growth. Fertilizing pole-size and larger trees is likely to provide the best economic return. Chemical analysis of walnut leaves can indicate current nutrient element levels of the trees and suggest probable response to fertilization. More...


Some sites don't have enough moisture to grow good black walnut trees. Unless other factors are limiting (and this is often the case), irrigating such sites may help to maintain tree growth during periods of inadequate precipitation and/or high evapotranspiration. But keep in mind: it probably won't pay to irrigate just to increase the value of merchantable trees. More...

Pruning and Thinning

Pruning and Thinning are two management techniques which can lead to higher quality stems. Corrective pruning may help create a dominant terminal shoot and lateral pruning helps create a defect-free log by eliminating branches. Thinning reduces competition, allowing the best trees to get the resources, but early on that competition is critical to force the trees to grow straighter with few branches, so timing is critical.

Corrective Pruning

Young black walnut trees may fork or produce multiple leaders when their terminal shoots are damaged by frost, insects, animals, or humans. Because a walnut tree must develop a single, straight stem for valuable lumber or veneer, corrective pruning is often needed to remove lateral branches that compete with the terminal for dominance. But pruning can also cause a tree to grow more slowly by removing part of its food manufacturing plant, the crown. More...

Lateral Pruning

One thing that makes some walnut wood valuable is something it doesn't have: defects. But defect-free wood can be produced only after a branch has fallen off the tree or been removed. Black walnut trees do not prune themselves readily. Even small branches tend to leave stubs when they die, and large branches may hang on the tree for many years after they die, so lateral branches must be pruned to produce high-value, knot-free wood. More...


Thinning is one of the most important silvicultural practices available to tree growers. It is particularly important with black walnut because walnut trees differ widely in value, depending on their quality and size. Thinning a walnut stand can greatly increase its value by making all the moisture, nutrients, and light available to a few high-quality trees and by removing the low-quality trees. Deciding when and how much to thin requires some care. More...

Thinning your black walnut stand the second time is much like thinning it the first time except that you face tougher decisions about which trees to keep. Most of the poorest trees have already been removed. More on subsequent thinning...

Crop Tree Management

Crop tree management (CTM) is a relatively simple and easy to use tree management system well-suited to small woodland ownerships. By Lenny Farlee, Extension forester, Hardwood Tree Improvement & Regeneration Center. Reprinted from the December 2013 issue of the bulletin. See the full article here.

Releasing Walnut in Natural Stands

Black walnut trees generally grow singly or in clumps in natural stands. To make the most of their potential value, you'll need to give these trees some “elbow room” from nearby trees and vegetation that compete with them for moisture, nutrients, and growing space. For individual trees in natural stands, release is the most important and worthwhile silvicultural treatment you can apply. More...

Revitalizing Stagnating Stands

Has your plantation or natural stand of black walnut trees stopped growing rapidly enough in height and/or diameter to meet your objectives? If so, your stand may be stagnating; and the first step in revitalizing it is to look for the cause. More...

Information adapted from Walnut Notes, Burde, E. Lucy, 1988. Source: St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station.

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