Treesearch

Forking in the opposite-branched sugar maple and white ash can cause trouble. Forks always occur in the large overstory trees that we depend on for the final crop. Quality of the main stem drops on forked trees-along with merchantable volume-and the risk of crown or tree breakage increases in managed stands.

Interest in clearcutting young northern hardwood stands in strips is running high, especially now that mechanical fellers and skidders have been developed to harvest these stands. Strip cutting has several advantages-no overstory to worry about when treating the site, no overstory to remove later, and the economic advantage of cutting the strip only once.

The aspen type covers the most area in the Lake States, followed by northern hardwoods. Both prefer good soil and are easy to regenerate. Because of past cutting practices, though, the types are now mixed over large areas. Usually there is an overstory of fast-growing aspen interspersed with an understory of dense hardwoods.

Yield tables were generated using STEMS (Stand and Tree Evaluation and Modeling System) developed by North Central Forest Experiment Station scientists. The data fed into STEMS came from real 1/4-acre plots. The plots were selected to characterize 40-year-old stands that averaged 58 percent of basal area in red maple, 23 percent in sugar maple, and the remaining 19 percent in yellow and paper birch, ash, elm, and aspen. One projection was made for unmanaged stands and one for managed stands. The purpose was to compare the gains produced by bringing stands under management.

Stocking, structure, and cutting cycle-how do they affect growth rates? To understand the interrelations we need first to understand the terms.

Historically, assessments of the forest resource situation have focused on timber supply, and the data used to support the assessments came from traditional forest inventories designed to provide reliable estimates of timber volume, growth, removals, and mortality (U.S. Department of Agriculture, Forest Service 1982). The most recent assessment included data and analysis of forest resources other than timber, including wildlife, range, water, recreation, and other resources associated with the Nation's forest lands (U.S. Department of Agriculture, Forest Service 1989). Future forest...

Rodents play a large but often ignored role in northern hardwood regeneration. They exert a major influence on seed supply and seedling survival.

At present, direct seeding of hardwoods in the Lake States is more of a supplemental than a primary means of artificial regeneration. Direct seeding may be used to augment a poor seed crop or increase the proportion of a preferred species. In the future, it will no doubt play a bigger role-in anticipation of this we need to collect and store the amounts of seed needed. With direct seeding, stand treatments would not have to be scheduled around good seed crops, species composition could be carefully controlled, and genetically superior seed could be sown. "Immediate" regeneration would be...

Northern red oak is extremely difficult to regenerate, although it has produced good acorn crops nearly half of the last 32 years in northern Wisconsin. Field trials have shown that for successful seeding, you must protect acorns from predation by wildlife and sow them when temperatures are most favorable for germination.