Site preparation often is necessary to create a good environment for natural or artificial regeneration. Its purpose may be to expose mineral soil for natural or artificial seeding or to reduce competition from undesirable vegetation or both. Site preparation may best be done before a stand is harvested (especially for hardwoods) if it is likely that large amounts of woody debris will remain after the harvest. Such debris would make it hard for site preparation equipment to reach the area. If woody debris will be piled or windrowed, it may be best to do site preparation work after the harvest. Ask a forester which treatments fit your conditions. Mechanical scarification may be needed to expose the mineral soil and mix it with duff. This can be accomplished by whole tree harvesting (where the whole tree, branches and all, is skidded to the landing rather than just the main stem) and dragging harvested trees over a different route with each load or by dragging a tree top around the stand after harvest. Machines also are available for disking, scalping, rock raking, and trenching.
Burning may be prescribed to remove logging debris or a heavy layer of organic material (such as moss and leaves) or to suppress existing woody vegetation. Prescribed burning requires a burning permit and must be done by a competent and well-equipped fire crew. Fire will kill young conifers, but many hardwood trees and shrubs, particularly oak, will resprout after a fire. Burning may give seedlings a fair chance to compete with resprouting vegetation. Burning is occasionally done before a harvest, but more often is done afterward.
Herbicides are available to kill most any herbaceous or woody vegetation. However, they may not discriminate between your crop trees and weed trees. Foliar applications (spraying herbicide on the leaves) are commonly used for site preparation. Depending on the herbicide, target species, and stand density, herbicides may be applied as a spray (large droplet size) or mist (small droplet size). Backpack sprayers are appropriate for small areas while large areas will require tractor-drawn sprayers. Herbicides are sometimes applied before harvest (especially in hardwoods) to kill vegetation that will compete with natural or artificial seeding. Herbicide usually is applied to young conifer stands after harvest to reduce competition from hardwoods. It may make sense to delay such an application until one or more years after harvest. In addition to depleting root energy reserves, the delay gives woody vegetation a chance to sprout after logging, thereby exposing more leaf surface to contact with the herbicide.
To avoid killing desirable young hardwood trees, cut them off close to the ground before applying herbicide. They will resprout the next year. To avoid killing desirable herbaceous plants, apply herbicide late in summer or early fall after they have produced seed and their tops have naturally died back.