Mesic Xeric Foothills 14-20 PZ

Description

This forested site occurs across the landscape as a mosaic of plant community phases characterized by variation in forest structural stage (tree age, density and cover) and plant community. Pathways between these phases are defined by historic fire regimes. Historically, many dry pine forests would have cycled from a shrub-bunchgrass initiation phase (1.1) to a young forest stage (1.3) to a mature forest phase (1.4) with a fire regime characterized by frequent surface and mixed fires. Fire exclusion can lead to closed canopy and dense understory stocking conditions represented by Communities 1.2 and 1.5 which can be more vulnerable to stand replacing fires. The Reference Community within this state is that of an open, mature, savanna like ponderosa pine stand represented by Community Phase 1.4. Historical evidence suggests that this community type was common across the landscape prior to selective logging and widespread fire suppression, which can alter fire regimes, reduce understory cover, and lead to a greater frequency of high severity fire. Given the likelihood that this state, even in the best condition and highest potential, will almost always include at least some component of exotic species regardless of management inputs, this may also be referred to as the “Current Potential State”. In this document, the term “reference state” is used synonymously with “Current Potential State” for the sake of simplicity.

Dominant plant species

1. ponderosa pine (Pinus ponderosa), tree

2. antelope bitterbrush (Purshia tridentata), shrub

3. Idaho fescue (Festuca idahoensis), grass

Submodel

Description

Represents all conditions where the site may be converted for pasture or cropland purposes.

Dominant plant species

1. orchardgrass (Dactylis glomerata), grass

Submodel

Description

In this state the stand is used primarily for timber harvesting. This may result in a number of manipulated community types and pathways depending on strategies surrounding harvest, weed control and replanting. Shelter-wood production systems may be favored due to the detrimental effects of drought and heat on ponderosa pine regeneration. Selective harvest of ponderosa pine will favor dominance of more shade tolerant species overtime. Broadcast burning of bitterbrush may help increase ponderosa pine reestablishment. Cheatgrass and other exotic pioneer species will likely increase following timber harvest on sites where they were previously present.

Dominant plant species

1. ponderosa pine (Pinus ponderosa), tree

2. Douglas-fir (Pseudotsuga menziesii), tree

Submodel