Treesearch

Spatial configuration and distribution of landscape elements have implications for the dynamics of forest ecosystems, and, therefore, for the management of these resources. The forest cover of Champaign County, in east-central Illinois, was mapped from 1940 and 1993 aerial photography and entered in a geographical information system database. In 1940, 208 forest patches amounted to 1,998 ha (or 0.8% of the county area). These patches had a mean area of 10 ha, a mean perimeter of 2,016 m, a mean perimeter to area ratio of 330, a fractal dimension of 1.47, and a mean nearest neighbor...

There is a growing interest in reconstructing past disturbance regimes and how they influenced plant composition, structure and landscape pattern. Such information is useful to resource managers for determining the effects of fire suppression on vegetation or tailoring prescribed fires to restore community and landscape diversity. In the spring of 1995, the National Park Service reintroduced landscape-scale prescribed fire to an extensive oak/pine woodland-savanna-glade complex on Turkey Mountain, Buffalo National River, Arkansas. We took advantage of this opportunity to: (1) reconstruct...

Differences in ground cover (percent cover of litter, percent cover of vegetation and litter weight) in old-growth forests across this region are not well understood. We initiated a long-term study in a three-state region to enhance knowledge in this area. We present baseline results for ground cover and compare these data across productivity regions. Thirty 0.25-ac (0.1-ha) main plots and 120 subplots 27 ft² (2.5 m²) in size were established in each old-growth forest and used to inventory ground cover. We estimated percent cover of: bare ground, boles of woody vegetation, dead leaves,...

Shelterwood harvesting of mature oak (Quercus spp. L.) stands on productive sites often fails because fast-growing intolerant and already established tolerant species outcompete oak reproduction for dominance of the advance regeneration pool. We hypothesized that prescribe fire would improve the competitive position of oak in the advance regeneration pool of shelterwood stands because of different growth strategies among species.

Soil net nitrogen mineralization and nitrification rates were studied on nine relatively undisturbed, forested watersheds in an effort to explain the large variations in nitrate export in streamflow within the Chesapeake Bay region. The primary hypothesis tested was that nitrate export from the watersheds was positively associated with rates of net soil nitrogen mineralization and net nitrification in the upper 10-cm of mineral soil. Rates of soil net nitrogen mineralization and net nitrification were measured over a 5-week summer incubation period (June-July) using nine buried bags in...

Eastern hardwood forests originated after catastrophic disturbances around the turn of the century and are currently an even-aged, maturing resource. The increasing value of sawlogs, especially those of particular species and quality, has prompted many forest landowners to increase their harvesting efforts. Most harvesting appears to be economically driven, focusing on sawlog extraction without regard to the future of the residual stand. Partial cutting practices, such as diameter limit cutting, remove the highest quality material and leave inferior species and quality behind. None of...

The study evaluated the influence of root collar diameter, number of large lateral roots, preplanting-root treatments (biostimulant called Roots and a moisture loss retardant called supersorb) and tree shelters on 1-0 black walnut (Juglans nigra L.) and northern red oak (Quercus rubra L.) seedlings. Four years after outplanting, the survival of black walnut and northern red oak increased with the number of large lateral roots. The difference was significant (p < 0.05) for black walnut but not for northern red oak. Total seedling height was significantly affect by tree shelters. The height...

Regenerating mature oak stands on better sites is difficult on the Allegheny Plateau because of abundant advance regeneration of faster growing competitors. We have observed that oak stands on the Allegheny National Forest (ANF) in northwestern Pennsylvania almost always regenerate to cherry-maple rather than to oak-hickory stands. Such conversion greatly concerns land managers and the general public. We surveyed 30 stands, varying in size from 8 to 42 acres, in a 786 acre compartment on the Sheffield Ranger District to document typical responses of oak-hickory stands on good sites to...

In the Lower Mississippi Alluvial Valley (LMAV), restoring bottomland hardwood forests has attracted heightened interest. The impetus involves not only environmental and aesthetic benefits, but also sound economics. Financial incentives to restore forested wetlands in the LMAV can come from federal cost share programs such as the Conservation Reserve Program and the Wetlands Reserve Program (WRP), which provide easements and funding to cover planting costs. Forestry led Mississippi agriculture production in 1995, testimony to the importance of timber. This project is designed to test four...

This study examined the potential role of hardwood leachates in the reduction of understory forbs in oak-hickory stands following invasion by sugar maple and dense-canopy shrubs. We conducted a shaded greenhouse experiment during two summers using stonemint dittany (Cunila origanoides (L.) Britton) as an indicator species. We used a modified stair-step bioassay with donor pots producing two levels of recycled leachates from hardwood seedlings root exudates, foliage washes, and decaying leaves. At the lower density, each donor pot had three hardwood seedlings and three applications 300 cm?...