State and Private Forestry - Pacific Southwest Region

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State and Private Forestry 1323 Club Drive Vallejo, CA 94592 (707) 562-8921

South Sierra Shared Service Area

Providing forest health technical assistance, training sessions and technology transfer to approximately 8 million acres of federal land, including:

Six National Forests:

Eldorado, Inyo, Lake Tahoe Basin Management Unit (LTBMU), Sequoia, Sierra and Stanislaus

Two National Parks:

Death Valley
Sequoia-Kings Canyon
Yosemite

Unique Features

The major insects and diseases in the South Sierra Shared Service Area are similar to other areas in northern California. What is unique, however, are the challenges of managing these pests in special locations where pest treatments can be controversial.

Pest Issues from 2010:

In 2010, bark beetles continue to cause a large majority of conifer mortality observed in the South Sierra Nevada. After successful attack, most conifers decline over the course of a year, not displaying symptoms until the following summer; therefore, mortality detected in 2010 were most often attacks that occurred in 2009. Associated damage agents and disturbances such as root disease, dwarf mistletoes, wildfires, or mechanical damage contributed to physiological tree stress and decline, increasing susceptibility to bark beetle infestation. Overstocked or areas with dense understory brush were particularly affected and vulnerable to attack – most likely due to prolonged water stress caused by recent drought. Some highlights of the most common bark beetle activity in the service area:
- Western Pine Beetle-caused mortality was especially devastating in older pine plantations in the Sierra and Stanislaus National Forest: High Sierra Ranger District experienced group-kills of 50-60 trees within the Nutmeg Plantations (south of Dinkey Mountain) and scattered pockets of 25 trees/acre kills along east Big Creek watershed; Groveland Ranger District were detected with smaller losses of 10-15 trees per group per acre but numerous around Gravel Range. Ground surveys determined that mature stands where diameter ranges from 12-25 inches were most susceptible.
- Mountain Pine Beetle activity continues to be severe in east side and higher elevation locations of the service area. Whitebark stands within the northern end of the Inyo National Forest are in the fifth year of outbreak losses: north by Lee Vining, down around Whitney Portal campground. Mortality groups averaged 8 trees per acre, but where activity has been on-going (June Mountain, Hilton Lakes, south Mammoth Lakes) continues to experience up to 10-30 whitebark or lodgepole trees lost per acre.
- Jeffrey Pine Beetle levels appear to have slightly increased in east side forests, compared to 2009 where overall activity was decreasing. Incidences of up to ten tree group kills were widespread near Bald Mountain and Glass Mountain, with smaller group mortalities dotted throughout the Inyo National Forest.
- Fir Engraver associated mortality doubled in 2010 from previous year estimates. The largest polygons with detected mortality in all southern Sierra forests were noted as fir engraver-killed white firs. Activity within polygons was often minimal: most averaged 1 tree per acre. However east of Portville and Three Rivers, Western Divide Ranger District was found with patches 200-900 acres in size, averaging 2-8 trees per acre. Georgetown and Amador Ranger Districts on the Eldorado National Forest were also detected with large areas of white fir mortality. Mortality from fir engraver is commonly associated with other pathogens or stand conditions that may not be visible from aerial detection.
Piñon Sawfly was initially detected in 2009 in the Inyo Wilderness and Death Valley National Park where over 10,000 acres were detected with low to high levels of defoliation. Mono County was not flown in 2010, but ground surveys within Death Valley that summer found evidence of continued defoliation and high populations of sawfly. There has never been a written record of sawfly in the park, nor has the range of this insect been identified as far west as California. Damage assessments and population monitoring of piñon sawfly in Death Valley and in the county will continue in 2011.
Identifying and reducing risks associated with private citizens and commercial transportation of firewood within and into California. Cooperative efforts continue with other federal and state agencies to monitor and prevent the movement of non-natives/indigenous exotics into new uninfested territories. Preliminary training on potential insects and diseases that could be introduced into the state can be provided upon request.
This service area strongly supports programs that encourage bark beetle prevention and treatments that promote forest health. Project funding opportunities are primarily available through Western Bark Beetle Initiative. Please contact the service area to schedule field visits and discuss treatment options.
Hazard tree management. Efforts are aimed at improving our ability to recognize and mitigate potential hazard trees through training, monitoring, and documentation. Regional standardization guidelines are still under development.
Wet, heavy snow fall in the early months of 2010 caused a significant amount of limb and terminal breakage mainly in pine plantations. Although this is not a common occurrence, it may happen more often in upcoming years as plantations age and left untreated. Trees in overstocked stands develop tall whippy stems that are less resilient to snow loading and more prone to breakage.
Regional, district, or group Insect and Disease trainings are being offered to all land managers or support personnel upon request. Please contact Beverly to check current offerings or schedule training.