Table 3-22 identifies forest and woodland acreages in the Planning Area. Approximately 9 percent of BLM-administered surface in the Planning Area is dominated by a combination forest and woodlands, which are comprised of juniper, limber pine, mixed conifer with aspen, and ponderosa pine.
The BLM is responsible for implementing management to achieve desired goals for forests and woodlands. The existing plans for the Planning Area are designed to restore and maintain forest health, and forest management activities are directed in accordance with sound silvicultural and multiple-use practices.
Forests in the Planning Area provide important habitat for flora and fauna, including several threatened or endangered species, such as Canada lynx, and species currently considered to be candidate or BLM-sensitive species. Forests also play an important role in the ecological processes and functions of ecosystems, such as energy flow, water, and nutrient cycling.
Forests and woodland communities in the Planning Area include aspen woodlands, Douglas-fir, juniper woodlands, lodgepole pine, limber pine, spruce-fir, whitebark pine, and ponderosa pine. Forestland is land capable of producing 20 cubic feet of wood fiber from commercial species per acre per year. Commercial forestland is land that has not been withdrawn from forest product harvest by law or statute. Woodlands are areas that are not capable of producing 20 cubic feet of wood fiber from commercial species per acre per year. Woodlands range from small uniform stands to larger mixed stands of aspen, limber pine, and Rocky Mountain juniper. Woodlands are ecologically important, especially as wildlife habitat.
The western slope of the Big Horn Mountains in the WFO includes substantial mixed-age stands of ponderosa pine. These stands are generally confined to dryer, poorer quality sites. Douglas-fir, Engelmann spruce, sub-alpine fir, and lodgepole pine grow on north-facing slopes in both the Big Horn and Absaroka Mountains. Forestlands also are found on Rattlesnake Mountain, the West Slope of the Big Horn Mountains, Carter Mountain, and on isolated public land parcels adjacent to Shoshone National Forest in the South and North Fork Shoshone River, Wood River, and Newmeyer Creek watersheds. Most forestland management occurs on Rattlesnake Mountain.
Forest and woodland areas in the Planning Area provide seasonal habitat for numerous songbirds, small mammals, predators, and big game, with concentrations of elk in winter (refer to Section 3.4.6 Wildlife for additional information).
Stand productivity and vigor can be measured by the stand site index at a determined age, usually 100 years. Stand vigor is a general term that refers to the current growth and health of the stand; live crown ratio is a measure of stand vigor. For example, most stands with an average live crown ratio of 50 percent or more have vigorous growth; most stands with an average of less than 20 percent live crown ratio have poor vigor. Stand productivity can be measured by comparison to site index. If the site index is 75 feet at 100 years, but the stand averages 65 feet at 100 years, a factor such as high basal area or mistletoe might be decreasing stand productivity. Stocking can be measured by basal area for mature stands, and stems per acre for regeneration.
Indicators for forest and woodland health include endemic levels of native insects, disease, pathogens, and the levels of nonnative insects and disease. Numerous parts of the Planning Area have been affected by disease, insects, and pathogens. Bark beetle activity has increased since 2002, with numerous incidences occurring across the Planning Area. A Douglas-fir bark beetle epidemic has affected several thousand forest acres on mixed ownership land in the Shell Canyon area; the spruce beetle has affected several thousand forest acres on mixed ownership land in the Carter Mountain area (BLM 2009b). Smaller outbreaks and infestations also are affecting conifers in the Absaroka and Bighorn Fronts, and on Rattlesnake Mountain. Dwarf mistletoe, a parasitic seed plant commonly occurring in lodgepole pine, ponderosa pine, and Douglas-fir stands, can be found in forestlands throughout the Planning Area. Mistletoe causes growth loss, reduces vigor in trees, leaving them more susceptible to attack by insects, and can be difficult to treat due to inaccessible terrain in some parts of the Planning Area.
Prolonged drought in the Planning Area has weakened conifers and made them more susceptible to bark beetles, blister rust, and other stresses (BLM 2009b). Winters have been mild, exacerbating many of these biological stressors. Many of the mature conifer trees on public land have died or are dying. Many of the aspen woodlands, willow, and cottonwood forests found at mid to high elevations are declining as succession from deciduous to conifer (typically juniper/ponderosa pine) dominance proceeds. Conifer species are replacing cottonwood-dominated and some willow-dominated riparian areas. The loss of deciduous forestland vegetation is affecting watershed, riparian, and wetland function and stability and diversity of habitat. This loss is human influenced due to fire suppression and the introduction of nonnative invasive species. Throughout the interior west, aspen are declining (Bartos 2001; Bartos 1998; Rogers 2002). Older aspen stands are more susceptible to cankers, conks, and decays in the bole. Conifer succession is occurring in most aspen stands, which will likely result in further reductions in aspen presence. Barring any major surface disturbance (e.g., fire and mechanical treatment), conifers will eventually replace most of the aspen stands (Wyoming State Division of Forestry 2001).
Douglas-fir stands vary in size from seedling-sapling stage to mature stands. Mixed and mature Douglas-fir stands vary in size from 1 to 20 inches in diameter at breast height (dbh), and from 1 to 120 feet in height. Trees with a dbh greater than 20 inches are an exception. Stand age ranges from 1 to 250 years. The Douglas-fir forest type ranges from healthy stands to those declining in vigor and productivity. Current age‐class distribution is unbalanced toward mature stands, and there is a lack of late‐successional Douglas-fir forests (BLM 2009b). Any future wildland fire disturbance in mature overstocked stands poses the risk of returning the entire forest type to an early‐succession stage.
Spruce-fir stands vary in size from seedling-sapling stage to mature stands. Mixed and mature sub-alpine fir–Douglas-fir–Engelmann spruce stands vary in size from 1 to 20 inches in dbh, and from 1 to 140 feet in height. Trees with a dbh of more than 25 inches are an exception. Stand age ranges from 1 to 250 years. The spruce-fir forest type ranges from healthy stands to those declining in vigor and productivity. Current age‐class distribution is unbalanced toward mature stands; there is a lack of late‐successional spruce-fir forests (BLM 2009b). Any future wildland fire disturbance in mature overstocked stands poses the risk of returning the entire forest type to an early‐succession stage.
Mixed and mature lodgepole stands vary in size from 1 to 20 inches in dbh. Trees with a dbh of more than 20 inches are an exception. Stand age ranges from 1 to 150 years. The lodgepole pine forest type ranges from healthy stands to those declining in vigor and productivity. Current age-class distribution is unbalanced toward mature stands, and there is a lack of late-successional lodgepole pine forests (BLM 2009b). Any future wildland fire disturbance in mature overstocked stands poses the risk of returning the entire forest type to an early-succession stage.
Although not considered a commercial species, limber pine is an important food and cover source for birds and other wildlife. Blister rust has affected limber pine in the Planning Area. Blister rust can infect all five needle pines, of which limber pine is an example, and can kill both mature and sapling trees. Limber pine has experienced mortality throughout the Planning Area, especially in Ten Sleep Canyon and Grass Creek (BLM 2009b). There do appear to be some mature and sapling stage trees in these areas that are not infected, which might suggest some natural genetic resistance to the disease. These are apparently resistant trees in large infection zones.
Aspen occupies a variety of sites ranging from steep, rocky slopes to lower, moister areas. Aspen reproduces rapidly after fire, regenerating primarily by suckering from underground rootstock. Fire control has led to a substantial drop in aspen regeneration and overall clone health. There are pure and mixed stands in and adjacent to the Big Horn and Absaroka Mountains, where conditions satisfy ecologic requirements for aspen. Aspen stands typically exhibit a diversity of understory vegetation, are used by wildlife and livestock, can serve as a natural fire break, and often occur as part of an important riparian/wetland component in the forest system. Due to past and present management practices, natural disturbances such as wildfire have not occurred in their historically cyclic way. As a result, most aspen stands in the Planning Area are remnant stands encroached upon by conifers (BLM 2009b). Aspen stands are generally overtaken by mixed conifer stands with a fire return interval of more than 100 years in this area. Most aspen stands have decreased in size and vigor over the past decades.
Juniper woodlands are typically comprised of Utah juniper stands, sometimes mixed with Rocky Mountain juniper and limber pine, on steep slopes and ridge tops. After long periods without fire, juniper species encroach into and dominate sagebrush communities. The fire return interval in juniper woodlands depends on the terrain. In shallow, rocky soils, the fire return interval is more than 200 years (BLM 2009b). Juniper woodlands have increased in size over the past decades (BLM 2009b). Juniper invasion into rangeland sites in deeper soils is partly the result of a departure from the historic fire return interval. There are past studies and historic photos of Enos and Grass Creeks that quantify encroachment. Most juniper woodlands have vigorous growth and few insect pests or diseases limiting their growth.
Forest resources harvested in the Planning Area consist of small stands of ponderosa pine, Douglas-fir, lodgepole pine, aspen, and aspen/conifer mix. Wood products harvested in the Planning Area include saw timber, firewood, Christmas trees, posts and poles, and biomass used for fuel, paper, compost, and insulation. Juniper and limber pine species not traditionally used in commercial wood product markets dominate woodland areas.
Existing plans set forest management levels for the Planning Area. The annual allowable harvest level was set at 1,000 thousand board feet (mbf) for the WFO and 500 mbf for the CYFO (BLM 1988; BLM 1990). The annual allowable harvest level is not specified for the Grass Creek planning area (BLM 1998a).
Most mature stands are on terrain inaccessible or too steep for equipment, not economically feasible to harvest, or are in areas administratively excluded from active forest management, such as WSAs or isolated tracts of BLM-administered land that have no legal access.
There is one commercial sawmill company presently operating near the Planning Area in Livingston, Montana. The sawmill in Cody, Wyoming, closed in 2006. There also are small, family operated businesses that engage in small, local sales for specialized products when available. There is a local market for firewood and post and poles.
Although there is regional demand for timber products from BLM-administered lands in the Planning Area, at present, forest productions from BLM-administered lands play a small role in the wood product industry. Engineered-wood product and biomass industries are currently insignificant in the region due to lack of regional industry infrastructure, and the high costs of transporting products to distant manufacturing plants.
The combined sawlog volume for the Planning Area offered from 1993 through 2002 averaged 518 mbf per year. The sawlog volume offered from 2003 through 2009 increased to an average of 1,040 mbf per year (BLM 2009b; Neighbors 2010). The increase in volume offered was the result of aggressively treating and preventing the spread of bark beetles.
From 2003 through 2009, approximately 1,150 acres of noncommercial mechanical forest treatments were completed via combinations of service contracts, stewardship contracts, and seasonal fire and fuels crew labor (BLM 2009b; Neighbors 2010). These forest management treatments included precommercial thinning, ponderosa pine ladder fuels reduction, and aspen treatments. Many aspen treatments involve cutting conifers within aspen clones, lopping and scattering conifer slash to create a fuel bed, and prescribed burning. This is followed by monitoring the suckering response and constructing a temporary solar-powered electric fence if excessive browsing exceeds new growth.
Management challenges for forests, woodlands, and forest products in the Planning Area include the lack of a natural fire regime and fuels management (see Section 3.3 Fire and Fuels Management); management of fragmented and isolated stands; encroachment of woodland species into other vegetation types; lack of a current forest inventory; declining or over-mature stands; and management of native and nonnative disease, insects, pathogens, and invasive species. The Healthy Forest Restoration Act of 2003 (102[e]) directs BLM field offices to identify management to protect old-growth trees and their equivalent associated with hazardous fuel reduction projects.
There are several insect and disease concerns that could compromise future forest health. Given recent trends in bark beetle infestations, it is likely that infestations will continue into the future and require further management action. Often, infestations occur on isolated tracts that are inaccessible and are not documented unless they show up on aerial flights or adjacent landowners inform the BLM of the problem.
The wood product industry has diversified, and forest products from public lands could be used to fill niches such as chips, shavings for animal bedding, house logs, biomass for rehabilitating disturbed areas, bulk for landscaping, compost, possibly alternative fuels such as pellets, and the traditional logs, firewood, posts and poles. These industries are not present in the local area, but could enter the area in the future. The mill in Saratoga could resume operations in the future. However, the cost required for road construction, traditionally appraised in the stumpage value of the sale, could result in administrative costs more than proceeds from the forest.
Climate change could be playing a role in recently observed changes in forest health. Forest communities are resilient in responding to normal variations in weather and climate to which they are adapted. However, increases in forest insect infestations and tree mortality throughout the Planning Area might be partly due to climatic factors such as warmer and drier summer conditions and warmer winters, acting in combination with other variables such as long-term fire suppression, particularly in areas where stands are overstocked.