This ecological system occurs on the upper east slopes of the Cascades in Washington, south of Lake Chelan and south to Mount Hood in Oregon. Elevations range from 610 to 1220 m (2000-4000 feet) in a very restricted range occupying less than 5% of the forested landscape in the east Cascades. This system is associated with a submesic climate regime with annual precipitation ranging from 100 to 200 cm (40-80 inches) and maximum winter snowpacks that typically melt off in spring at lower elevations. This ecological system is composed of variable montane coniferous forests typically below Pacific silver fir forests along the crest east of the Cascades. This system also includes montane forests along rivers and slopes, and in mesic "coves" which were historically protected from wildfires. Most occurrences of this system are dominated by a mix of Pseudotsuga menziesii with Abies grandis and/or Tsuga heterophylla. Several other conifers can dominate or codominate, including Thuja plicata, Pinus contorta, Pinus monticola, and Larix occidentalis. Abies grandis and other fire-sensitive, shade-tolerant species dominate forests on many sites once dominated by Pseudotsuga menziesii and Pinus ponderosa, which were formerly maintained by wildfire. They are very productive forests in the eastern Cascades which have been priority stands for timber production. Mahonia nervosa, Linnaea borealis, Paxistima myrsinites, Acer circinatum, Spiraea betulifolia, Symphoricarpos hesperius, Cornus nuttallii, Rubus parviflorus, and Vaccinium membranaceum are common shrub species. The composition of the herbaceous layer reflects local climate and degree of canopy closure and contains species more restricted to the Cascades, for example, Achlys triphylla, Anemone deltoidea, and Vancouveria hexandra. Typically, stand-replacement fire-return intervals are 150-500 years with moderate-severity fire-return intervals of 50-100 years.
Information Source: http://www.natureserve.org/explorer/