2017 Report on the Health of Colorado’s Forests — Colorado State Forest Service

Click here to read the report. Here’s the executive summary:

Executive Summary

Each year, the Colorado State Forest Service (CSFS) prepares a report on the health of Colorado’s forests to inform Colorado’s General Assembly, citizens and other stakeholders. The report provides an overview of current forest conditions, the forces shaping them and some of the actions being taken to address related challenges. This year, the publication also o ers a special section describing ways in which the state is dealing with millions of standing dead trees, as well as how it is managing those forests at continued risk of insect mortality.

Native forest insects and diseases are important to the ecology of all of Colorado’s forests, often setting the stage for the replacement of older trees with younger, more vigorous ones. However, these same organisms can impact the benefits society derives from forests, including wildlife habitat, recreation, timber production and watershed protection. Regular monitoring for the damage caused by forest insects is a fundamental aspect of forest management, and in Colorado the primary source of this information is an annual aerial forest health survey conducted cooperatively by the CSFS and U.S. Forest Service (USFS), Rocky Mountain Region.

Based on the 2017 survey, spruce beetle was Colorado’s most widespread and damaging forest insect pest for the sixth consecutive year. A total of 206,000 acres with active infestations of this bark beetle were observed in high-elevation Engelmann spruce forests, with nearly a third of these acres not previously infested. Counties most significantly impacted by spruce beetle in 2017 included Gunnison, Fremont, Hinsdale, Saguache and Chaffee. Mature Douglas fir trees also continued to be attacked and closely related bark beetle – impacting a total of 14,000 acres in many of the same counties, and several others in the central and southern portions of the state.

Besides the impacts of these bark beetles, in 2017 western spruce budworm defoliated 252,000 acres of Douglas fir, white fir and spruce in Colorado, with the most heavily impacted areas including the Sawatch, Mosquito and Culebra ranges; Sangre de Cristo Mountains; and the Tarryall Mountains in Park County. White fir continued to be attacked and killed by fir engraver beetle in Ouray and Archuleta counties, though tree mortality occurred on fewer acres than in 2016. And damage caused by a complex involving western balsam bark beetle and several species of root-decaying fungi continued to be ubiquitous, causing tree mortality on 50,000 acres of high-elevation subalpine fir throughout the state. Emerging, or currently more
localized, insect and disease threats also exist in Colorado’s forests. The exotic pest emerald ash borer (EAB), first detected in Colorado in 2013, continues to spread in the urban and community forests of Boulder County, and in 2017 was detected for the first time within the City of Lafayette. A needle cast fungi a effecting lodgepole pine forests on Vail and Monarch passes caused localized areas of premature needle drop, and a rapidly increasing outbreak of roundheaded pine beetle in Dolores County continues to a effect more acres of ponderosa pine each year – with more than 10,000 cumulative acres impacted since 2012.

The Gunnison Basin has been dealing with the state’s most serious bark beetle outbreaks, in part due to prolonged drought conditions. Several programs and methods currently are being employed to deal with this growing concern, including the Western Bark Beetle Program, the use of pheromone treatments to repel attacks on susceptible trees, and use of the Good Neighbor Authority to allow state contracting procedures to be used for management efforts on federally owned lands.

Nearly 3.4 million acres of Colorado’s pine forests have been impacted by the mountain pine beetle since 1996, and another 1.78 million acres of Engelmann spruce have been affected by a similar forest insect, the spruce beetle. Together, these bark beetles have caused widespread tree mortality on roughly one-fifth of Colorado’s forestland over the past two decades. But the problem of dead and dying trees in the state’s forests also offers an opportunity: standing dead trees can hold value for years, and currently are being utilized by wood products businesses in efforts that support forest management efforts.

The CSFS and its partners are working with sawmills and forest products businesses statewide to seize this opportunity. Colorado has more than 100 sawmills, ranging in size from small mobile operations to large-scale permanent facilities, and an estimated one-third of these mills use beetle-killed trees as part of their wood supply. Several specific areas and programs related to meeting the challenges of dead trees are addressed in this year’s report. More than a decade after the mountain pine beetle epidemic moved through Grand County, dead trees from over 30,000 acres of private and state land have been sustainably harvested and processed into valuable wood products. And cooperative efforts between the CSFS and its partners are providing opportunities to derive value from Colorado’s standing dead trees, including research with Colorado State University to determine how long wood remains usable after being killed by beetles or fire. A primary focus of these efforts has been at the site of the 2013 Black Forest Fire.

In locations throughout Colorado, CSFS and USFS e orts also are providing access to capital to support the state’s sawmills. These efforts not only help enable forest management, but create jobs in places like the San Luis Valley, where a new mill now employs almost 50 full-time workers from the surrounding area. Besides the need to address dead trees on the landscape, the need to manage forests with a focus on healthy trees – especially those at higher risk for future insect and disease concerns – remains an ever-present priority. To better deal with ongoing forestry challenges, the CSFS is proactively realigning its organizational structure, with changes beginning in 2018. All CSFS field offices will remain open, and the agency restructure will provide enhanced opportunities to fulfill the CSFS Five-Year Strategic Plan to foster healthy and resilient forests.

From Aspen Public Radio (Elizabeth Stewart-Severy):

The report examines the impacts of widespread infestations of bark beetles. The insects have killed roughly one-fifth of Colorado’s forests in the past 20 years. The trend continued in 2017.

More than 200,000 acres of Colorado’s high-elevation spruce forests were infested with spruce bark beetle last year. Another beetle that attacks Douglas firs impacted 14,000 acres in the southern part of the state.

Temperature and precipitation can affect forest insects. According to the Colorado Climate Center, the average temperature in the state has increased two degrees since the 1980s. Water temperatures are also warmer. The report says these factors contribute to insect and disease outbreaks.

The state forest service report also focuses on dealing with the dead trees. Colorado has more than 100 sawmills, but that’s not enough to harvest and process all the beetle-kill wood.

There are several programs in the state to minimize impacts of bark beetles, including using pheromone treatments to repel the insects.

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