Forests are habitat for many naturally occurring insects and diseases. While often called "pests" these insects and diseases often persist at endemic levels without causing widespread mortality. Weakened or stressed trees and the alignment of ideal climatic variables can cause insect and disease populations to reach epidemic levels where widespread mortality can degrade the visual environment and cause a cascade of impacts to water and nutrient cycling, wildlife habitat suitability and wildfire threat.

Ips

The last decade has brought periods of drought to the Front Range of Colorado, and this has resulted in an increase in Ips engraver beetle activity. Ips beetles are in a family of insects called "bark beetles". Adult bark beetles lay their eggs beneath the bark of trees, and the young beetles, called larvae, create a network of galleries in a thin layer of tissue that transports nutrients in the tree. The collective damage from the galleries can kill the tree if enough beetle larvae are present. Multiple generations of Ips beetles can hatch within one summer, resulting in rapid increases in populations if suitable conditions exist.

Various species of Ips beetles live in small diameter conifers or the canopies of larger diameter conifers and kill or wound the Academy's ponderosa pine, spruce, Douglas-fir and white fir. Over the past few years, the Academy has actively removed thousands of infected trees as soon as they are located in order to prevent the build-up in populations. While the majority of impacted stands were thinned to densities that will make them more resilient to Ips beetles, the increases of vigor to the stand may take years to realize. The Academy continues to monitor Ips populations and mitigate infected trees. The Academy's Natural Resources office is also partnering with Air Force Academy Cadets to improve the monitoring of Ips populations. These effots have proven successful in drastically reducing the beetle mortality in conifers.

Western Spruce Budworm

Defoliating moths have recently begun to impact the forests of the of greater Rampart Range/Monument Creek landscape. One of these moth species is present on the Academy and Farish, and is currently causing defoliation of spruce, fir, and Douglas-fir. Western Spruce Budworm larvae emerge in the spring and consume the last year or more's new growth. Like the Ips beetle, multiple generations can occur within a year. When populations increase and defoliations continue for multiple years, mortality can occur.

At present, mortality from Western Spruce Budworm is limited on the Academy and Farish. North facing slopes on the upper-elevations on the Academy are being defoliated and some mortality is occurring. At Farish, populations are small, but increasing, and mortality from Western Spruce Budworm has not been observed. While the population is cyclical, the Academy is planning projects that will increase the vigor of trees in impacted stands and reduce understory trees that are necessary for the Western Spruce Budworm to complete it's life cycle.

The forests of the Front Range of Colorado were historicallyshaped by frequent, low intensity fire. This resulted in open stand conditions and favored fire-resistant species such as ponderosa pine and Douglas-fir that have thick cork-like bark. On some slopes and certain elevations, less frequent, high intensity fire favored fire-resilient species that rapidly resprout following a fire such as quaking aspen and gambel oak. Fire suppression over the past century has been fairly successful at keeping fires small. This resulted in widespread increases in surface fuel and ladder fuel loading in lower elevation forests, which would have otherwise been consumed by the frequent low intensity fire. These altered stands are now at much greater risk to burning at a high intensity, which would have many undesirable effects to communities, the visual landscape, watersheds, and certain wildlife species. Past wildfires on and near the Academy have disrupted training exercises and resulted in the closure and evacuation of residents and employees. Each year many small fires occur from lightning strikes, training exercises, or arson, but these fires are quickly suppressed.

The Natural Resources offices and Fire and Emergency Services have been working together to reduce the threat of fire to the Academy. Each year, hundreds of acres of the Academy receive fuels reduction treatment, through mechanical or hand treatments and in some cases using prescribed fire. Fire and Emergency Services and the Natural Resources have been working with Academy residents to reduce fuels next to homes and structures, and provide education to residents about fire safety and preparation. The Academy is recognized for our forest and fuels management efforts by the Arbor Day Foundation as a Tree City USA and by the National Fire Protection Association as a Firewise Community®.

The Academy relies on natural regeneration and on-site seedling transplanting projects to maintain its forested areas. With the current overstocking and change in stand conditions, the natural regeneration from standing seed sources provides an abundance of new seedlings. The natural regeneration will be kept in check with fuels mitigation projects and prescribed fire where possible. Reducing the density of the seedlings will lessen competition and help produce a more resilient forest landscape. Transplanting projects will take existing seedlings and replant them in recreation areas such as lakes and trails.

Increasing temperatures and altered precipitation are causing rapid changes in the forest. We expect to lose the majority of the spruce and fir trees. They prefer the colder and wetter habitat which is rapidly decreasing at USAFA.

At Farish, stands of quaking aspen are reaching maturity and beginning to reach their age limit and die. To maintain and enhance these stands, the Academy has established several small regeneration units where the disturbance of cutting has encouraged aspen sprouting. Today, these regeneration stands are fenced to protect them from elk damage. When the regeneration stands reach suitable diameter and height, the fencing will be removed. Additional harvest units will be added in the future to maintain a diversity of age classes.

Urban Forestry