Mesic Xeric Slopes and Flood Plains (Oregon white oak-Ponderosa Pine Hot Moderately Dry Shrub)

Description

In pre-European times oak stands were more open due to frequent low intensity ground fires every 5 to 30 years, many started by native Americans. Conifers like ponderosa pine and Douglas-fir were not a dominant part of the overstory. Native grasses, sedges, and shrubs were abundant in the understory. Large diameter oaks existed due to less competition from other oaks and conifers.
Major insects affect white are western oak looper, western tent caterpillar, and Pacific tent caterpillar. Major diseases are armillaria and oak anthracnose.

Major insects that cause mortality in ponderosa pine are the western pine beetle, mountain pine beetle, and pine engraver beetle. The western and mountain pine beetles can kill mature to old growth pine. The pine engraver beetles attack and kill young pole size stands. Drought and tree to tree competition cause stress which increases bark beetle mortality. Other insect concerns in pine include the following defoliators: Pandora moth, pine butterfly, sawflies, and needle miners.

Major ponderosa pine diseases include Annosum and Armillaria root rot, commandra rust, and elytroderma needle disease, Dwarf mistletoe is a major concern infecting over 25 percent of ponderosa pine acreage. It is more serious in the drier ponderosa pine sites. It also can spread more readily in dense stands lacking frequent fire cycles. Douglas-fir mistletoe can also be a concern when Douglas-fir occurs.

Submodel

Description

Long intervals of fire exclusion have increased stand density in oaks and advanced the encroachment of pine and fir. Ladder fuels increased by shrub layer Much of the area in this condition. Stand replacing or mixed severity fires are the norm with the loss of larger diameter oaks. Oak can replenish site through sprouting, however, wildlife habitat loss due to large oak mortality.

Submodel

Description

Throughout the history of settlement these oak stands were near lower elevation areas used by the indigenous people and European settlers. Respective to that, these oak stands have been altered by cutting, overgrazing, and conversion to other land uses.

Submodel