The last week in February marks National Invasive Species Awareness Week, a week that highlights…
Creeping Conifers
As the valley is blanketed with snow, many things look different. The river turns icy, the geese populate spring waters, and steam rises from houses and businesses alike, but one thing that remains constant is the presence of evergreens along the ridgelines. While the presence of these needle-ly trees fulfills my desire for festivity and vitality in the winter months, the threat of the advancing tree line is more evident once the snow melts.
Since 1953, conifers have expanded into 200,000 acres of sagebrush habitat in Southwest Montana, according to the Southwest Montana Sagebrush Partnership (SMSP). The excessive growth of conifers, such as Rocky Mountain Juniper, Limber Pine, and Douglas Fir, has been facilitated by several factors. A primary factor is long-term fire suppression. In a natural environment, wildfire is a useful tool to suppress conifer growth, while giving low-growing species, like grasses, shrubs, and forbs, a chance to establish. Changes in land-use and grazing patterns has also helped conifers expand in our area.
Despite the potential for these trees to serve as carbon sequesters, the risk they pose to the high divide habitat is substantial. Overgrowth can increase plant pest pressure and promote terrestrial habitat loss, such as that of our sagebrush ecosystem. This land often represents important forage for livestock, and browsing for deer, elk, and pronghorn. As conifers grow, they create a thick canopy that shades out many ground species, creating a monoculture. The absence of diverse plants and varying root systems can disrupt soil structure and cause erosion and nutrient depletion. Conifers are also known for their substantial water uptake (another characteristic that allows them to outcompete other plant species). As they use more groundwater, there becomes less surface water running through our streams and rivers.
Conifer growth is also a main contributor to the decline of aspens in the region. The SMSP reports that 70-80% of historic aspen habitat in the Beaverhead-Deerlodge National Forest has been lost to conifer expansion.
The change in vegetation, from grassland to conifers may also contribute to more severe and longer-lasting wildfires in the future. Fires in grassland regions often move quickly and are a fairly low intensity, allowing vegetation to return more quickly. The addition of trees, specifically conifers, to landscape, provides a greater source of fuel for wildfire.
In 2023, the Natural Resource Conservation Service (NRCS) initiated a Targeted Implementation Plan (TIP) to address conifer encroachment in Madison County. The South Tobacco Roots Rangeland and Conifer Encroachment TIP involved 12 landowners and covered 12,415 acres, primarily in sage-steppe ecosystems. One of whom, Terry Todd, was excited to join the TIP, to help reduce wildfires, increase stream flows, and create better habitat for wildlife and for his 500 cattle. The plan highlighted brush management via chainsaw or heavy equipment, and prescribed grazing as potential ways to thin the conifer population. Prescribed burns have also been historically used to manage conifer expansion on Wisconsin Creek, Laurin Creek, Pierce Canyon, Preacher Creek, and above Virginia City.
If this issue is growing close to home, contact your local NRCS office for more information at 406-842-5741.
Sources:
https://www.nrcs.usda.gov/sites/default/files/2022-09/Montana-TIP-South-Tobacco-Roots.pdf
Related Posts
Comments (0)