02/27/2008 Env Bd Packet - Laserfiche WebLink

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• trend, producing young stands of Maple- Basswood Forest. The mesic stands often grade into drier stands of Maple- Basswood Forest, but differ from them by having a somewhat denser shrub layer and the herbs woodrush (Luzula acuminata) and pointed - leaved tick- trefoil (Desmodium glutinosum) in their understory. In general, most existing stands of Oak Forest have been disturbed by grazing or selective cutting, or have been fragmented by development. Natural stands of mesic Mixed Oak Forest are rare. Drier stands are more common, in part because relative to the mesic forests they occur on sites with soils less suitable for cultivation. Additionally, dry Oak Forests may have increased in extent somewhat following fire suppression, succeeding from oak savanna and woodland. Disturbed stands of oak forest commonly have dense subcanopies of prickly ash, or of the exotic species common buckthorn and Tartarian honeysuckle, which have also now invaded many undisturbed stands. Disturbance through grazing may also be partly responsible for the lack of regeneration in Oak Forests, especially in stands with heavy soils that compact readily with trampling. A comprehensive plant species list for Foxborough's Oak Forest restoration area is provided in Appendix B of this report. Lowland Hardwood Forest Lowland Hardwood Forest is a wet -mesic forest that is present throughout Minnesota. It is transitional between the terrestrial and palustrine systems, occurring on sites with seasonally high water tables (within the tree - rooting zone) but that do not flood regularly and that have mineral rather than peat soils. In accord with the poorly drained sites on which the Lowland Hardwood Forests occur, species tolerant of periodic soil saturation dominate the tree canopy. American elms and black ashes are common canopy dominants, but most stands are mixed, with slippery elms, rock elms, basswoods, bur oaks, hackberries, yellow birches, green ashes, black ashes, quaking aspens, balsam poplars, and paper birches as important species. The tall-shrub layer is usually discontinuous and is composed of a mixture of upland and lowland shrubs. The ground layer is composed mostly of upland herbs that do not root to the water - table. Lowland Hardwood Forest usually occurs in fire - protected areas, although even in unprotected areas the community burns infrequently because the woody vegetation is usually hydrated, especially in the spring. Lowland Hardwood Forest soils differ from Hardwood Swamp Forest soils by being mineral rather than peaty and from the mineral soils of other mesic upland forest types by being seasonally saturated (at depths greater than 0.5 meters). Lowland Hardwood Forest is often composed of late - successional species, but few stands in Minnesota have old canopy trees, presumably because of windthrow and infrequent episodes of killing floods. Lowland Hardwood Forest is topographically transitional between upland forests and forested peatlands and is best developed on flat terrain where such transition zones are broad (e.g., on river terraces above normal flood levels, on loamy ground moraine, and on drumlin fields). Currently, there are no recognized subtypes or sections of Lowland Hardwood Forest. Following further field review, stands of Lowland Hardwood Forest may be reclassified as wet subtypes of Aspen -Birch or Aspen Forest, or dry subtypes of Hardwood Swamp Forest. A comprehensive Foxborough Conservation Development Restoration and Management Plan 17