Upland Hardwood Management

Upland hardwoods are a very important habitat type for much of our wildlife in Virginia. Some hardwoods should be retained on any property where wildlife habitat is a management goal. Some may need to be harvested and others may need some work to keep the stand growing well and to improve their quality for wildlife.

Regeneration of upland hardwood stands that are dominated by oaks is a process that is not easily controlled by management. Basically on your poorer sites oaks will come back almost regardless of what you do. These are the sites that foresters generally recommend for conversion to pine due to the long rotation age and poor quality of the native hardwoods. On your extremely good sites it is probably safe to say no one has come up with a way to bring oaks back. On the intermediate quality sites it may be possible to bring oaks back with a shelterwood cut. This cut involves reducing the overstory down to a level of about 45 sqft/ac basal area, then several years later removing the remainder of the trees in a final harvest. The number of years between the two cuts is determined by how long it takes to get an adequate number of vigorous oak seedlings established. A period of from five to fifteen years will suffice depending on the timing and size of mast crops. One significant benefit of a shelterwood is that during the period between cuts the site provides high quality wildlife habitat. It should be kept in mind that the production of oaks on these intermediate quality sites may not give a strong financial return. If current trends in hardwood prices continue however, these sites may be profitable for growing hardwoods. In any case it is impossible to guess at timber prices 40 to 80 years into the future. Besides using a shelterwood cut, a very clean clearcut can be used to regenerate oaks on these medium quality sites with a reasonably good prospect of success.

On small tracts of land it is certainly desirable to release crop trees when they have reached about 25 feet in height. At this point they have already demonstrated their dominance and vigor and it will be relatively easy to select preferred trees. Competing trees with adjacent crowns should be removed by either cutting or herbiciding. It should be kept in mind that this is a labor intensive task that will not pay for itself economically until the timber reaches maturity, at which time the improvement in the stand quality will be significant.

Thinnings are as important in hardwoods as they are in pines. Unfortunately, it is usually difficult to get them done. Whenever possible you should try to thin these stands as soon as it is commercially possible - 40-50 years old. It may be possible to thin a second time in approximately 10 to 15 years. Residual densities in hardwoods should be fairly similar to those for pines at about 55 sqft/ac (50-65) on the first thinning, and perhaps five to ten square feet higher on successive cuts. In thinning hardwood stands it is important for wildlife benefits to maintain a high degree of species diversity. Keeping about 50-60% of the trees in oaks, evenly divided between red and white oak groups is a good goal. Although the timber value is less it is important to retain hickories, beeches, black gums and maples. These trees all provide valuable food to a wide variety of wildlife species. Also large hollow trees should be kept wherever possible because of their value as den sites. With the almost certain arrival of gypsy moths in the area in the next several years it is important to maintain both vigor and diversity in upland oak stands.

Prescribed burning should be precluded from hardwood stands unless they are very young (< 5-10 years) or very old (> 65 years). In seedling stage hardwoods fire can be very helpful in encouraging oaks and hickories. As the trees get into the sapling and pole stages fire will cause serious damage due to the thin bark. Fire should always be precluded from high site quality hardwoods regardless of age.