Mixed Conifer

A healthy mixed conifer forest boasts a mixture of conifer species that thrive in the Swan Valley's temperate climate. MPG North spans late and early succession conifer forests. Multi-species, multi-aged forests resist catastrophic losses to diseases and insect pests, and provide greater habitat diversity for wildlife. Healthy late succession forest at MPG North contains Douglas-fir (Pseudotsuga menziesii), western white pine (Pinus monticola), and western larch (Larix occidentalis) in the overstory; ponderosa pine (Pinus ponderosa) may emerge from the canopy. This forest has a multi-aged understory of Englemann spruce (Picea engelmannii), grand fir (Abies grandis), and subalpine fir (Abies lasiocarpa). Pinegrass (Calamagrostis rubescens) dominates the herbaceous layer of a late succession forest. Healthy early succession forest contains a high density of lodgepole (Pinus contorta), ponderosa, western larch, and Douglas-fir. Shade intolerant species dominate the shrub layer and a mixture of forbs interspersed with pinegrass dominates the herbaceous layer. Unhealthy mixed conifer forest is generally the result of logging operations that altered stand and soil characteristics over much of the area. These activities, along with intermittent forest fires, encouraged the growth of lodgepole pine (Pinus contorta) stands throughout the area. Near monoculture stands display a narrow age range, and contribute to larger forest fires and more bark beetle outbreaks than multi-age stands. In addition, these even-aged stands offer a sparse understory with fewer habitat niches for wildlife to flourish. At MPG North, some logged areas (those with extreme soil compaction and exotic grass competition) failed to regenerate even a lodgepole pine monoculture. This allowed exotic grasses and exotic forbs to dominate the plant community and alter soil processes. Now, these soils lack an organic layer and prevent seedling regeneration. Trees must be hand planted and nurtured to establish in this harsh environment. The desired future condition for unhealthy forest habitat like lodgepole monoculture stands and poor-regeneration clear cuts is an uneven-aged, multi-species forest that supports a diversity of wildlife. We will retain snags in forested areas, and add coarse woody debris to create a deeper organic horizon and reduce soil compaction. Eventually, the use of artificial disturbances will promote a diversity of early and late succession forest types.


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