Green Horizons

To manage your forest effectively, it should be divided into compartments called stands. Stands are areas of the forest that have similar species composition, soils and topography. Often the term "stand" is used flippantly to describe an entire forest or boundary. But this broad use of the term indicates a misconception that can seriously impact the effectiveness of any prescribed forest management activity.

Silviculture refers to the care and cultivation of forest trees. The stand is the basic unit of silviculture; much like a field is the basic unit on the family farm. Silvicultural prescriptions should be developed at the stand level, not for the entire forest that is normally a collection of stands.

However, silviculture is also one of the most abused terms, especially when it comes to hardwood management. To ease management decisions and silvicultural prescriptions, it is common to lump a number of stands together and write a single prescription for the entire area. This approach can easily lead to misapplication of treatments over a significant number of acres. The loss of potential future timber values and subpar regeneration can be so subtle that the landowner may never even realize the loss!

Foresters who are good silviculturists recognize the need to analyze a forest thoroughly and clearly define stands. Only after stands are properly delineated can prescriptions be developed to meet the needs of each stand.

Good stand delineation is particularly important in naturally regenerated hardwood stands because many are highly diverse topographically and historically. Issues such as high-grading (harvesting the best trees and leaving low-quality junk trees to populate the next forest), fire and grazing all may combine to create a number of different stands with varying species, age and quality. Often, each stand will need a different silvicultural prescription to optimize owner objectives.

Variables that should be considered when delineating stands in hardwood forests include:

• Soil characteristics (generally determined from soilmaps)
• Topographic or landscape position
• Species composition of the overstory
• Species composition of the midstory and understory
• Presence of advance regeneration (when required for preferred species)
• Size and age of the overstory
• Timber quality and value

Soil and topographic position determine the potential productivity for tree growth. Topographic position affects soil moisture available for tree growth and, in the case of bottomlands, excessive moisture that can hinder tree growth. Soils and topography are generally related, but this is not necessarily always the case.

All of the other variables are biological and relate to the character of the trees and forest. It is easy to delineate stands that are dramatically different in age or species composition. The acid test for the professional forester comes when, everything else being equal, they can determine the difference between sites with regard to other variables.

Stand Delineation Example
Figure 1 shows a topographic map of a 115-acre hardwood forest at the MU Wurdack Research Center in Crawford County, Missouri. As with reading all maps, north is assumed to be at the top of the map. The following provides information on each stand and a harvest prescription specific for that stand. The silvicultural harvest prescription was founded on ownership objectives for immediate income while improving the ability of the forest to maximize incomes in the future and increase the diversity of wildlife habitats.

Stand 1. This stand is characterized by large white oaks with very sparse understory. A fence extends along the west side of the stand allowing cattle to have access to the stand where it joins a fescue pasture to the east. The fescue ground cover and the grazing have prevented the development of oak reproduction and other native woody vegetation. The stand represents an opportunity to demonstrate how forested areas that have been used to pasture cattle can be put into a silvopasture program. The larger diameter white oaks have value if cut as stave logs, thereby providing a return for restoring the understory or developing a silvopasture demonstration area.

Stand 2. The results of a recent (1998) timber harvest is most evident here as there are ¼- to 2-acre patches of seedling- and sapling-sized oaks. Pole-size trees are the most common. In five years, the sapling oaks in the openings should be thinned down by favoring those with the best stem quality. It would be a good place to demonstrate how growth can be focused on the betterquality trees by reducing competition.

Stand 3. This stand is composed of black oak poles and small sawtimber-sized trees growing along a long, narrow rocky ridge. There is evidence of red oak borer damage in many of the trees. It might be well to harvest all of the trees because of the borer damage and the poor growing conditions for oaks and convert the stand to shortleaf pine by planting. The returns from the harvest could be used to defray the cost of site preparation and planting. Shortleaf seems to do well on these narrow ridges as evidenced by the pole-sized stand of shortleaf growing on ridges just north and east of the Center.

Stand 4. This stand is on a northwest-facing “cove-like” landform with higher soil moisture levels which provides an excellent site for the growth and development of white and northern red oak. Stand density is good and composed of medium- and large-sized sawtimber white oaks. There are some pole-sized and larger pine trees (white, shortleaf and Scotch) at the northeast corner of the stand. This stand demonstrates how good sites provide excellent opportunities to grow quality grade white and northern red oaks. Scheduled harvesting could begin when the stand’s stocking level reaches 80 percent; estimated to occur in the next five years.

Stand 5. The stand is growing on a poor, rocky, dry, moderate- to steep-facing southwest slope. Exit holes made by red oak borers are evident on the trunks of many black oak trees. This is a marginal site for timber production because of poor site quality and steepness of slope. Removal of saleable black oaks would terminate red oak borer activity. This harvest could be in conjunction with the harvesting of the black oaks in Stand 3. As with that stand, Stand 5 should be converted to shortleaf pine.

Stand 6. This stand represents a large, flat drainage where post oak is the predominant species in the overstory. There is a deep gravel underlayment that makes the area drought-prone during the summer months. The upper soil layer has an accumulation of organic materials as a result of periodic heavy spring rains. This combination of a thin layer of fertile soil over a well-drained gravel underlayment supports a variety of plant species, including 14 tree species in the overstory. This stand falls below the site quality considered suitable for managing a timber resource. Removing most woody species while maintaining the post and white oaks along with the hickories should provide enough light to the forest floor for the development of native forbs and grasses. This activity in conjunction with periodic prescribed fire should make this area highly desirable to wildlife.

Stand 7. This stand is on the northeast-facing slope on the main ridge that borders the west and south side of the Center. This is primarily a white oak sawtimber stand with small pockets of regeneration that have filled in canopy openings following the 1998 harvest. There are some live large cull white oaks that were not removed during the harvest. There is little need to carry out any further activities within the next 10 years as stocking is just above the minimal level. If anything, removal of large culls for firewood would improve growing space and release advanced white oak regeneration.

The result of proper stand delineation is prescribing the right management activity(ies) on the right area(s) of your forest, thereby saving time and money! So, work with your professional forester to develop a plan that takes into account the characteristics of all the stands within your forest.