02/27/2008 Env Bd Packet - Laserfiche WebLink

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Reed Canary Grass dominated wetland edges, should be actively and aggressively converted and restored to a more diverse native vegetation type. The following are detailed descriptions of natural community types that have been prescribed for Foxborough's conservation areas, as depicted in Figure 6. Oak Forest Oak Forest is an upland deciduous forest with >30% oaks, and is common and widespread throughout much of Minnesota. It is most common on dry to dry-mesic sites in the deciduous forest - woodland zone but also occurs occasionally in the southern and western parts of the conifer - hardwood zone, and in stream valleys in the prairie zone. At least 30% of the tree canopy in an Oak Forest is made up of oak trees. Most often aspen, paper birch, or black cherry trees make up the remainder of the canopy. The actual composition of the community, however, varies considerably in response to variation in soil moisture, soil type, fire history, and climate. The driest stands of Oak Forest are dominated by northern pin oaks and white oaks, with black oaks, shagbark hickories, and sometimes bur oaks important in southeastern Minnesota. These stands occur on nutrient -poor, well - drained sandy soils on outwash plains, river terraces, and beach ridges. They have relatively open canopies, with between 70% and 80% cover. The canopy height is usually between 13 and 17 meters. Because of the open canopy, the shrub layer is often very dense. American hazel dominates the shrub layer, which also often contains gray -bark dogwood, blueberries, and blackberries. Some of the more common ground layer species are the sedge (Carex pensylvanica), wild geranium (Geranium maculatum), Virginia creeper (Parthenocissus inserta), wild sarsaparilla (Aralia nudicaulis), and hog -peanut (Amphicarpaea bracteata). Commonly, at least some of the oak trees in the dry stands have multiple stems and thick, spreading lower branches, indicating that these trees grew up in a disturbed and more open setting. Minnesota public land survey records indicate, in fact, that many of these dry stands were oak savanna or oak woodland before European settlement and with fire suppression have succeeded to forest. Oak regeneration is rare in these stands now, as the oak species reproduce poorly under forest canopies. In the absence of fire, relatively mesic or fire - sensitive species such as bitternut hickory, basswood, and red maple, are increasing in abundance in the community. Northern red oaks, white oaks, or bur oaks dominate the more mesic stands of Oak Forest. These stands occur on sites that had fewer severe fires before European settlement than the sites on which dry Mixed Oak Forest occurs. These mesic stands most likely were always forest, rather than woodland or savanna. They have tall (> 20 meters), straight, single - stemmed trees that lack spreading lower branches. Commonly, mesic fire - sensitive tree species are present with the oaks in these stands, especially in the understory. These species include basswood, green ash, bitternut hickory, big- toothed aspen, and butternut. The shrub layer in mesic stands is sparser than in dry stands and, correspondingly, the forb layer is denser and more diverse and there are more graminoid species. Like the drier stands, however, there is little oak regeneration, and most mesic Oak Forests appear to be succeeding to Maple- Basswood forest. Heavy selective logging of the oaks in mesic stands may accelerate this Foxborough Conservation Development Restoration and Management Plan 16