Hardwood forests are complex ecosystems and are much more unforgiving to site conditions than their softwood counterparts.
Hardwood forests typically contain a variety of tree and brush species. However, hardwoods, like pines can be artificially established and grown in plantation settings to achieve a desired timber production goal.
Why hardwood
Typically, hardwood forests are associated with multiple species, and trees of varying ages. The wide variety of species and ages within a hardwood forest may provide flexibility in ownership objectives but also offers many challenges. Landowner objectives may include wildlife benefits from hard and soft mast producing hardwood trees or high-quality sawlogs. Regardless of your goal, the distribution of small, medium, and large-size trees and species should be actively managed to meet any long-term property objective. Factors such as site, species, sustainability, and management must be addressed to effectively manage your hardwood forest.
Planting hardwood
View our guide for establishing hardwood seedlings. Learn about seedling storage, planting, environmental considerations, quality assurance and more.
Maintenance
Thinning
Thinning is a good technique to use on intraspecific competition. A false idea is that a thinned forest will not have as much volume left for a final harvest or regeneration cut. Yield is actually recovered from trees that would have died due to lack of resources. Tree growth and health are improved on the remaining crop trees which allows increased growth. This improved growth compensates for the amount lost by cutting trees during a thinning.
Density and spacing should be a priority when thinning a hardwood forest. Thinning should concentrate on undesirable species, suppressed, diseased, deformed, and low quality trees. Enough trees need to be harvested to ensure enough resources for the remaining trees, but not so many that tree form suffers.
Three major factors influence long-term growth after thinning.
- Timing. Early thinning can generate increased diameter growth when compared to a later thinning or no thinning at all.
- Post-thinning spacing and its influence over crown health and development. Thoughtful consideration should be given to what crop trees are chosen to remain on the site. If too many trees are removed allowing too much sunlight to hit the stem of the remaining trees, epicormic branches- small branches that grow on the trunk but do not serve a purpose in tree growth, can develop and reduce log grade and tree value. Windthrow may also be a concern for heavily thinned hardwood forests.
- Interval between thinnings. One or more thinnings may be required to ensure a landowner’s property goals are met.
Prescribed fire
Prescribed fire is a great way to combat interspecific competition for crop trees. Fire has served as a beneficial tool starting with early Native Americans who used fire as a tool in hunting, land clearing, and brush reduction. Prescribed burning is often associated with conifer forests; however hardwoods have also evolved with a lower intensity, less frequent fire regime. Fires helped with the natural succession process by lethally heating the vascular cambium of less desirable trees with thinner bark, naturally thinning and reducing competition.
Fire occurs more frequently on upland hardwood sites compared to bottomland hardwood sites. Upland hardwood species typically have thicker bark than bottomland hardwood species. The bark of desired hardwoods, such as white oaks, thickens as the tree grows in diameter increasing its resistance to fire-causing wounds.
White oak species have thick bark and are better at compartmentalizing wounds; thereby, enabling easier recovery after a fire. Several hardwood species have thick bark and are able to endure an infrequent fire regime. These species include red oaks, white oaks, American beech, maple species, hickory species, flowering dogwood, and black cherry.
Herbicide application
When used according to the label, herbicides are a useful tactic in defending a hardwood forest against both interspecific and intraspecific competition. Consider the following when choosing a herbicide:
- the chemical of choice is selected for the target species for control and the site restrictions
- timing of herbicide application
- application technique
Herbicide labels are legal documents delineating where and how a herbicide can be applied.
To find a forestry herbicide prescription that meets the needs of your property, visit the Forestry Herbicide Prescriptions tool.
Timber harvesting
Before you harvest your existing hardwoods, some planning needs to be done regarding the regeneration of the next forest stand. There are two methods of regeneration: natural and artificial.
Natural regeneration
Natural regeneration of oak and other hardwood is the most common method of regeneration primarily due to; the high cost of artificial regeneration, the lack of genetically superior stock, and the extended period of time until final harvest. Unfortunately, common land and harvesting practices have led to poor oak regeneration, less than desirable residual hardwood species, and high-graded stands. “High grading” thinning/harvest removes only the highest (best) grade of timber (i.e. the most merchantable stems) leaving poorer quality trees and/or undesirable species behind, reducing or eliminating future timber value. Research has shown that traditional hardwood regeneration practices are inappropriate (e.g. single tree selection) for successful natural regeneration of oak and other desirable hardwoods. Patch cuts of 3 to 5 acres each encourage oak regeneration.
Light quantity is the key to successful oak regeneration. Oaks do not regenerate in full shade. Consider that sunlight is 100% above the canopy, then oak seedlings at the forest floor require a minimum of 25% of full sunlight for growth and development. At best, oak seedlings only use about 50% full sunlight to fully drive photosynthesis. Light conditions above 50% will favor aggressive, shade-intolerant species (especially herbaceous species) that out-compete oaks. With today’s common practices, typical amount of sunlight reaching the forest floor is less than 10% full sunlight and often less than 5% which is far below the minimum requirement for oak regeneration.
Artificial regeneration
Each year, thousands of acres are being reforested with hardwoods across the South. While oak regeneration may be desired by landowners there are processes that need done in order to obtain a successful hardwood planting of at least 400 seedlings per acre at the end of the first year.
Commonly planted hardwood species include cherrybark oak, nuttall oak, Shumard oak, water oak, willow oak, white oak, and sweetgum.
Hardwood species are very site-specific. Particular sites need to be identified before planting or seeding. The best hardwood sites are rich bottomlands, stream terraces, coves, lower slopes, and north and east-facing slopes with deep, fertile, well-drained soils.
Newly planted hardwood seedlings cannot compete with natural regeneration. Planting hardwoods may not be necessary on harvested sites where desirable species are or will be established by nature.
Success depends upon a number of regeneration factors, including:
- Site appropriateness - tree species should be properly matched to site conditions.
- Site preparation – proper preparation of the site and improvement of problematic conditions including control and reduction of competing vegetation .
- Seedling quality – consider seedling size, root density, and potential vigor.
- roper handling and planting of seedlings – care should be taken in the handling of seedlings from the nursery bed, through transportation and storage, and planting.
- Competition control – controlling competing vegetation during the establishment phase.
Timber stand improvement
The growth of oak trees planted 9 feet apart on a good site begins to slow at or soon after age 10. At this time, the intraspecific competition (oaks competing with oaks) for sunlight, nutrients, water and space begins to limit production of carbohydrates (plant food) and growth slows. As a result, a precommercial thinning (before trees have market value) should take place between 10 and 15 years which can either be mechanical (if biomass market) or herbicide injection.