REV88252 - Laserfiche WebLink

Home Browse Search

• • Vegetation Information East Facing Transitional: Map Unit Name: Not distinguished on the map. General Description: This is the smallest unit found on the site, even smaller thaz the riparian and transitional riparian vegetation. Most of the topography on this site faces either north or south or is contained in drainage courses. The ridgelines are very sharp and vegetation boundaries equally abrupt. Most of the ridgelines divide into small ridges as they extend eastward toward Turkey Crec;k and the mountain front. But even the subdivided ridges exhibit abrupt transitions from north to south facing slopes. However, in the shallow swales between these subdivided ridges can be found small stands of vegetation that appear to form a distinct unit on this site. Although Gambel Oak is found on both north and south facing slopes as well as the tr:msitional areas in the valley bottoms and along the ridge crests, it rarely achieves a typical grove-Gke growth pattern in those areas. In these shallow swales that generally face east and exhibit fairly gradual slope. gradients, Gambel Oak forms a major part of the vegetation. The growth is dense and robust often reaching ]0 to l5 feet in height and a density that can barely be penetrated while walking. These small stand:> of Gambel Oak occupy locations where the soil is deep, drainage is good, and moisture fairly reliable. In many ways this unit is like the dense Gambel Oak stands along the mountain front from Douglas County southward into New Mexico. But unlike those stands that may dominate tens or even hundreds of acres, these form small patches rarely more than a few thousand feet in extent. Soil/Plant Relationships: The nature of the soils in these groves is difficult to determine with accuracy. It appears to be a highly organic, gravelly loam containing large amounts of oak roots and oak leaves in various degrees of decomposition. These small patches of vegetation and soil ma~• be the most valuable soil resource on the site. V/henever these dense oakbrnsh areas are encountered,tFe soil should be carefully salvaged. Few of the other soils on the site are worth saving and most soils arc: not practical to save because of the very steep slopes. But these oakbrnsh dominated areas are generally on gradual slopes and do not appear to contain the lazge amount of rock found in most other soils. The pH is probably close to neutral, but the organic matter content is similar to that found on the north facing slopes. Cover Characteristics: Cover in these areas is very close to 100% and nearly all of that cover is canopy cover produced by the oak. Ground cover, however, is also very high and is estimated at SO% to 90%. Tree cover is present but forms a minor component of the vegetation. It is not clear whether these oak dominated stands are succeeding to forest or whether the oak is displacing the forest. Indicators are present that support both developmental pathways. A third option is that this unit forms a stable unit that might be equated with the archaic term "edaphoclimax." This term refers to a vegetation th.3t has achieved a climax state but is controlled by soil factors rather than climatic factors. The term is rarely used in modern plant ecology anymore, but describes the situation with these oak stands very well. Menzer Quarry Amendment Exhibit J Page 7