Forest Habitat Group
1)
Describe the habitat (Alexander 1987, Arno 1980, Cole 1990, Covington et al. 1994,
Green and Conner 1989, Hann 1990, Knight 1994, Montana Bird Conservation Plan
2000, Mumma 1990, Peet 1988, Peterson 1995, Smith 1980):
a)
Historic conditions: Historically, fire-free intervals have been long in
the high elevation conifer forests, typically 100 to 300 years. Because of the cool, moist climate in the
subalpine zone, the risk of fire is less than in warmer climates, and
relatively few acres have burned in the last 300 to 400 years. Fires that did occur were usually
stand-replacement burns of various sizes.
Regeneration after hot burns often required several decades for
establishment, and it took 300 years or more for succession to return the
forest to its original condition.
Patches of native insect and disease outbreaks were part of the normal
ecological process. Spruce-fir
communities may have contained a larger component of young age classes compared
to communities today. Whitebark pine was
probably more abundant and widespread in northwestern
b)
Present conditions: High elevation
conifer forests occupy some of the coldest and wettest sites in the
The high elevation zone has had changes
similar to those of the mid elevation zone but to a much lesser degree. Recent increases in the growth and density of
high elevation conifer species have been documented throughout western
2) Identify
the issues:
a) Use: During the early settlement of the late 1800s and early 1900s, the primary uses were mining and forage for sheep. Since the mid-1900s, there has been a steady trend toward a set of values for these ecosystems that are more noncommodity in nature, such as hiking, camping, horseback riding, and viewing wildlife or scenic features. Winter recreation use has especially increased recently due to better equipment such as snowmobiles, snowshoes, and cross-country skis. Because of the diversity and rugged beauty of high elevation lands, people find enjoyment in various activities in these areas. Today the community is considered more important for recreation, wildlife habitat, and watershed protection than as a source of timber, mining, or grazing.
b) Access: Over 2,500,000 acres (1,011,750 ha) of high elevation conifer forest are in public ownership; the remaining 325,000 acres (131,530 ha) are privately owned. A large proportion of these ecosystems is protected as wilderness, which prohibits mechanized equipment, reserves them from commercial timber use, and limits the range of recreational activities. Remoteness and rough terrain have also discouraged exploitation, but difficulty does not preclude use and is attractive to many. Improved equipment like snowmobiles, snowshoes, and cross-country skis has allowed increased access in winter, even in wilderness areas.
c) Problems: Impacts from human developments, pollution, and disturbance to natural processes have been relatively low in the high elevation conifer forests compared to other ecosystems. However, these slow-growing communities are sensitive to disturbance by humans and the consequences can be highly visible. The introduction of white pine blister rust, which attacks whitebark pine, and the introduction of exotic plants (e.g. mountain knotweed) have resulted in significant problems. Trail and campsite degradation, packstock impacts, development of use-created trails around lakeshores, litter, and loss of solitude are all problems or potential problems in some places. There is a potential for increased recreation such as downhill ski areas and off road vehicle travel. Logging activities, though presently limited, could be a potential problem.
d) What
has been the cause of change to the habitat: Historic logging, mining, and livestock
grazing locally changed high elevation conifer forest community patterns, but
these effects have not been broad scale.
The results of fire suppression in the subalpine zone, however, have
been broad scale, although to a much lesser degree than in other forest
communities. Natural fire frequency
cycles are relatively long in the high elevation zone and successful ignitions
are infrequent. Consequently, fire
suppression has been relatively successful.
Since fire frequencies are typically 100 to 300 years, the effects of
fire suppression on individual communities have not caused a change from what
is present naturally. The primary effect
is that the pattern of communities is becoming more homogeneous; old
communities are maintained, while adjacent communities that were once young are
now becoming old. The amount of
communities in an early seral stage, compared to mid and late seral stages, is
much less. In addition, recent increases
in the growth of many high elevation conifer species have been documented
throughout western
3) Priority bird species in
High Elevation Conifer habitat in
Level I:
Level II:
Level III:
1) Describe the
habitat (Ferry et al. 1995, Green and Conner 1989, Gruell 1980, Knight 1994,
Uchytil 1992):
a) Historic conditions: Pure or mixed stands that included limber pine, Douglas-fir, lodgepole pine, blue spruce, ponderosa pine, and aspen. Historically, the land surface was less forested, in an earlier successional stage, and had more canopy perforation; however, all tree species present today were represented historically. Less frequent (80 to 150 years) but more intense stand replacement fires occurred. The aspen component was greater due to more intense fires. Less ungulate use than in the present. Higher beaver concentrations and more influence than in the present.
b) Present
conditions: Mixed conifer; pure or
mixed stands that can include limber pine, Douglas-fir, lodgepole pine, blue
spruce, and/or ponderosa pine; can include aspen. Lodgepole pine is most common and can cover
extensive areas; it covers more acres than any other forest type in
2) Identify the issues:
a) Use: Wildlife cover and food (e.g. lodgepole pine seeds
are an important food for birds and mammals, and needles are an important
winter food for Blue Grouse), timber harvesting (lodgepole pine is one of
b) Access: The density of roads from logging and recreation has increased, allowing access to virtually all parts of this habitat type. The majority of this habitat type is publicly owned.
c) Problems: Fragmentation due to roads and trails, timber harvesting, rights-of-way, recreation, and home development; fire suppression; loss or reduction of the aspen component; decreased snag (standing dead tree) density; changing structure of the understory due to grazing and home development; feral and domestic cats; avian displacement due to human activities.
d) What has been the cause of change to the habitat: Fire suppression; timber harvesting and related management; increased recreation, such as downhill ski areas and off-road vehicle travel; increased human use.
3) Priority bird species in Mid Elevation
Conifer habitat in
Level
I:
Level
II:
Level
III:
1) Describe the habitat (Arno 1980, Bock et
al. 1993, Green and Conner 1989, Idaho Partners In Flight 2000, Knight 1994):
a) Historic conditions: Before 1890, frequent fires confined the low elevation conifer woodlands to rocky sites or the lee sides of slopes. Canopy fires were probably rare before European settlement, but fire scar data suggest that surface fires occurred on average every 10 to 25 years. The effect of fire in the low elevation was to create open savannahs and patchy, park-like woodlands. Frequent surface fires killed young seedlings and saplings but, because of their thick bark, the older trees were not usually killed and stands were dominated by mature and old growth trees. Frequent fires resulted in low heavy-fuel loading of the forest floor and understory that, in turn, reduced the ability of fire to reach the overstory and completely destroy the stand. Insects and diseases were present but usually killed only individuals or small patches of trees. Understory vegetation was dominated by bunchgrasses and forbs.
b) Present conditions: In eastern
2) Identify the issues:
a) Use: Livestock grazing, commercial timber harvesting, firewood cutting, wildlife use, recreation (e.g. shooting, rock climbing, off-road vehicle travel, camping, etc.), mineral extraction, home sites, and tree removal for landscaping are major uses.
b) Access: About 500,000 acres (202,000 ha) of the ponderosa pine type are in public ownership; the remaining 905,000 acres (366,000 ha) are privately owned. Most of the 736,000 acres (298,000 ha) of Douglas-fir forest are in the national forests. The community’s low elevation and close association with foothill grassland and shrub areas expose it to more intensive activities of humans than most western forest types. Access and use are increasing in association with the urban interface.
c) Problems: Its low elevation and openness expose the habitat to more intensive human activities than most western forest types. Poor silvicultural practices have emphasized economic values over stand health and long-term condition. Fire suppression, livestock grazing, and logging act together to cause increases in tree density, heavy fuel loading, mortality in the oldest age classes of trees, insect and disease outbreaks, and fire severity and size. Other problems include encroachment of nonnative species (especially Canada thistle after ground disturbances), and urbanization (e.g. planting exotics; loss of habitat diversity; habitat fragmentation; domestic dogs and cats; exotic wildlife like European Starlings and House Sparrows; and increased predators like skunks, raccoons, and red foxes).
d) What has been the cause of change to the habitat: Three types of management activities have had the most influence on changing the nature of low elevation conifer forests: fire suppression, livestock grazing, and tree harvesting. In the past century, long-term fire exclusion has brought about dense, overstocked stands and large, continuous buildups of heavy fuel, particularly live-ladder fuels that could allow fires to crown and destroy the stand. Grazing impacts began in the late 1800s and early 1900s when large herds of domestic sheep and cattle were allowed to graze freely in the low elevation forests. The result was substantial damage to soils and vegetation, especially where herds were concentrated. Perennial bunchgrasses, in particular, are still recovering from the severe overgrazing of the early days. Today, grazing occurs at much lower densities, but localized damage to soils and vegetation may still occur where animals concentrate. Even today, livestock grazing removes herbaceous vegetation that provides fine fuels necessary to carry frequent, low intensity fires, causing fires to spread more slowly and burn hotter. Grazing also improves conditions for tree seedling establishment by reducing competition from grasses and forbs. Mature forest landscapes have been fragmented through timber harvesting, which has also selectively removed most of the large trees. Much of the old growth has been lost to logging, and the structure of many of the old growth stands that remain has been compromised by the dense growth of young trees. Many snags have also been removed, which is a loss of an essential resource for cavity-nesting bird species.
3) Priority bird species in
Low Elevation Conifer habitat in
Level II:
Level III:
1) Describe the
habitat (Bartos and Campbell 1998; DeByle 1990; DeByle and Winokur 1985; Dieni
and Anderson 1997a; Knight 1994; Mueggler 1988, 1989; Schullery 1995;
Winternitz 1980; Yellowstone National Park 1997):
a) Historic conditions:
Prior to the influence of European American settlers, aspen was probably
much more widely distributed than it is now.
b) Present conditions: About
467,000 acres (190,000 ha) of aspen is found throughout
A characteristic element among aspen communities is the luxuriant undergrowth that it supports compared to that in adjacent coniferous forests. This undergrowth frequently consists of three layers: tall shrubs, medium shrubs/tall herbs, and low herbs. Forbs generally dominate the herb component but, occasionally, grasses and sedges are equally abundant. However, changes in the grazing pressure of wild and domestic ungulates since European settlement have altered the nature and structure of the shrub/herbaceous component. Human influences have likely altered the understory community composition and associated use by avian species.
About
88 species of birds potentially use aspen habitats in
Most aspen regeneration occurs as root suckering; establishment from seed is rare. Therefore, aspen stands consist of a mosaic of clones, within which individual trees are genetically identical and have strong structural uniformity. Despite uniformity within clones, multi-clone stands often exhibit wide structural variation due to genetic and site differences among adjacent clones. Clone size averages ½ acre (0.2 ha) across the species range. Most aspen stands have well-defined overstory layers of relatively uniform height produced by the rapid regeneration of suckers following stand-replacement events. The majority of stems are produced during the first 4 to 6 years after disturbance; thus, stands with an equal representation of multiple age and size classes are rare. Multiple age classes develop when older stands begin to disintegrate or when disease or insects open the canopy and apical dominance declines, releasing understory suckers.
Following severe disturbances, such as stand-replacement fires or clearcutting, aspen usually dominates sites for many decades. On some sites, conversion back to a conifer-dominated stand occurs very quickly (<100 years), while on other sites, conversion may take many aspen generations and extend 300 to 400 years. The rate of stand conversion is determined by disturbance factors, proximity to conifer seed sources, and rate of conifer seedling growth into the stand canopy. Modern fire suppression practices and drought conditions have contributed to the loss of seral aspen stands and the decline of aspen regeneration throughout the mountain West. Remaining stands are often decadent and approaching their maximum age.
As
aspen sprouts become less common through succession and fire suppression,
livestock and big game in need of browse concentrate on those that remain,
which can lead to their further deterioration.
Heavy utilization can prevent aspen sprouts from growing into adult
height after a fire, as can heavy utilization in combination with a lack of
fire. Grazing by cattle and sheep has
been the primary consumptive use of aspen in
2) Identify the issues:
a) Use: Aspen-dominated woodlands provide food, cover, and breeding sites for many wildlife species; produce forage for domestic livestock; produce wood fiber; provide fire protection by acting as living firebreaks for the more flammable conifers; provide watershed protection; provide high yields of water; and are valued for recreation and scenic beauty.
b) Access: Most aspen habitat is on national forest land and is highly accessible to the public. The density of roads from logging and recreation has increased, allowing more access by vehicles.
c) Problems: Because of the decrease in severe fires resulting from modern forest fire prevention and suppression practices, natural succession is replacing aspen with conifers. Human development has brought a loss of habitat diversity, an increase in predators that are attracted to human habitation (e.g. raccoons, skunks, and red foxes), domestic dogs and cats, invasive plant species, and exotic wildlife like European Starlings and House Sparrows. Other problems include heavy grazing and trampling by wild and domestic ungulates; clearing for farming; heavy, high-intensity recreation; and climatic change, through lower moisture levels (which allow succession from aspen to sagebrush) and temperature extremes.
d) What has been the cause of change to the habitat: Fire suppression and over-grazing are the primary causes of change. Climate change to a more arid state, increased recreation, and the issues of human development have contributed to stress on aspen habitat.
3) Priority bird species in
Level I:
Level II:
Best
Management Practices
Various bird species that use forests have a diversity of requirements. Bird species respond differently to variation in forest characteristics such as vegetation composition and structure; elevation; hydrology; forest age; patch size; shape; special features such as snags, streams, or cliffs; surrounding land use; and distribution of forest stands across the landscape. A variety of habitats under different or rotating management schemes may be the best strategy across a landscape that encompasses public lands and diverse private lands, and may even cross state boundaries. Maintaining a variety of bird species requires the kind of forest management that maintains plant and habitat diversity. Many of the characteristics of forests can be manipulated to benefit birds; landowners and land managers can take a variety of simple and inexpensive actions to improve habitat for birds and help them nest successfully. By maintaining and restoring habitat for forest-dwelling birds, many other wildlife species will also benefit.
As
a landowner or land manager, the actions you take will depend on your goals,
resources, and commitment, as well as the physical characteristics of your
property, such as soil type, topography, and existing vegetation. The following Best Management Practices
(BMPs) should provide some reasonable guidelines for managing forest habitats
to benefit a wide variety of resident and Neotropical migratory birds in
Many of the Best Management Practices for forests fall into major categories of land use such as Forestry, Engineering, Grazing, Recreation, etc. The recommended BMPs are broken out into categories for convenience, although some are general enough to cross into other categories.
1) Take a conservative approach to management activities in forests. Because most trees take many years to mature, any miscalculations could have long-lasting consequences. Consider both long- and short-term impacts and/or benefits of any activities within or adjacent to forests. Recreation, development, fire suppression, and improper grazing in forests can reduce the multi-aged, multi-layered structure, including snags (standing dead trees) and diseased trees, most beneficial to birds.
2) Develop a long-range forest management plan at a landscape and even regional scale to manage for multiple bird species with different habitat needs while continuing to meet other resource objectives. For example, the value of an individual 100-acre (40-ha) patch of forest to birds varies greatly, depending on whether it is part of an extensively forested landscape or the only forest patch for miles. Also, landscape-scale land use patterns significantly affect the population levels of cowbirds and avian predators in the area. By managing habitat at the landscape scale, managers can contribute to the health of regional populations through their own local actions on the ground. Thus, a regional goal might be to maintain large tracts of relatively undisturbed or older forest in close proximity to other forest fragments or to tie into large region-wide systems of interconnecting forested habitats that encourage movement of birds within appropriate habitats.
3) Manage local forest stands to address goals set at larger scales. Maximizing diversity at the local scale could compromise landscape and regional diversity by fragmenting mature forest or homogeneous forest habitats. Instead, strive to meet landscape and regional diversity goals for forest types and age classes, and to complement the pattern of the surrounding landscape in a way that best accomplishes local and regional management goals.
4) Maintain all habitats (e.g. vegetation cover types and successional stages) and important habitat components (e.g. snags and forest floor complexity). Strive to mimic, retain, or restore presettlement proportions and distribution of forest types, successional stages, and habitat components.
5) Maintain plant species diversity and manage for a patchwork or mosaic of native plant communities and age classes across the landscape. Although some pieces of the landscape must be managed to the detriment of some species and the benefit of others, always maintain a sufficiently wide range of variability of critical structural characteristics across a broad landscape so that the habitat needs of most bird species can be met. Provide a variety of habitat conditions, but do not sacrifice old growth forests or large areas of contiguous forest and avoid using the same forest treatment everywhere.
6) Ensure that all age classes are present (seedling, young, mature, and decadent) in the forest, with more seedlings present than decadent trees, and more young trees than mature ones. Provide a balanced age structure while protecting and maintaining old growth forest where it occurs. This will provide a variety of structural characteristics that influence the kinds of food and cover available to birds, including density, spacing, and size of living trees; height, profile, and closure of the canopy; density and size of dead trees (standing and on the ground); and density, spacing, and profile of understory vegetation.
7) Provide multiple layers of plants, or “vertical vegetation structure”, in forest habitats. A diversity of bird life within a forest requires a high diversity of microhabitats with green vegetation at all heights. Many bird species nest and forage within 10 feet (3 m) of the ground, so it is critical to maintain a well-developed woody and herbaceous understory. Healthy forests have young trees, shrubs, and herbaceous plants that provide this layer. Shrubs and herbaceous plants are generally associated with open canopy forests that are of diverse structure and age. However, even in old growth conditions where canopy cover is high, patches of shrubs and herbaceous plants will develop where falling trees have opened the canopy.
8) Within extensive areas of forest habitat, manage for a patchwork or mosaic of different communities across the landscape. These may include wet meadows, bare ridges, aspen stands, healthy riparian vegetation, and interspersed shrub habitats. Mosaics support many bird species with different needs. Many birds that breed in forests utilize non-forested habitats for foraging, molting, migration, and pre-migration staging areas. For example, the Northern Goshawk breeds in mixed conifer forests, but forages in a variety of habitats; the Calliope Hummingbird frequents meadows, canyons, riparian aspen stands, willow thickets, and other shrubby areas within coniferous forests; and the Great Gray Owl nests in forests but often forages in meadows within the forest.
9) Maintain all old growth stands where they exist, and ensure the presence of multiple stages of mature forest on the landscape. Attributes of old growth forest include large snags, large trees, and conifer cones; managing for these attributes, and therefore old growth conditions, will benefit species such as the Brown Creeper, Golden-crowned Kinglet, and Red Crossbill. Provide for the development of future old growth by leaving areas unharvested for 100 to 200 years or more. Maintain large tracts of late-rotation forest which are relatively close to other forest fragments or which are part of large, region-wide networks of forest habitat.
10) Maintain forest in large, contiguous areas and maintain continuity between stands wherever possible to benefit area-sensitive species such as the Ovenbird. (An area-sensitive species is one that requires a large block of unfragmented habitat to successfully breed and survive.) Western forests are naturally patchy and habitat alterations should be designed to promote habitat interspersion and variety, but avoid converting forested land to other uses. Habitat fragmentation can result from land conversion to housing developments, mining, and agriculture. Avoid human-caused fragmentation and adjacent land uses that subsidize cowbirds and avian predators, including intensive livestock grazing, golf courses, human habitation, and recreation areas.
11) In areas with little forest or high levels of disturbance, preserve or restore even the smallest of forest fragments in an effort to provide some habitat for forest specialists and to provide important stopover sites for Neotropical migrants. Riparian bottomlands, ravine bottoms, and patches along lakeshores are particularly important. Develop a policy of “no net loss” of forest habitat (i.e. discourage loss and conversion of habitat, but when unavoidable, mitigate with equal or greater restoration efforts).
12) Allow or reintroduce natural disturbance patterns, including wildfires and insect outbreaks. As a result of disturbances, ecosystems should consist of a mosaic of patch types in varying stages of recovery, including a sufficiently large area that is in a recovered state. Develop treatments that restore the stand structure, composition, and patterns of presettlement disturbance regimes. Plan the size of treatment units to reflect the range of historic events. Although we do not know every habitat requirement for every species, we can assume that species present today evolved under natural processes in natural habitats, and that by preserving those processes and habitats, we can maintain healthy populations of the species that are associated with them.
13) Provide small-scale openings in the habitat. Openings create a diverse landscape that provides food for both seed-eating and insectivorous birds. Also, small mammal populations increase within cleared areas, which can attract predatory birds. However, openings are not good management for an intact forest community and should only be created in areas where they will not jeopardize a forest interior ecosystem. Openings should not be too large and the forest should not become fragmented. Limit clearing widths to 650 feet (200 m) to maximize use by bird species that nest in adjacent forests and include cleared areas in their territories. In ponderosa pine forests, cut 5- to 7-acre (2- to 3-ha) openings in sapling or small-pole stands (the least preferred by wildlife), and protect junipers, oaks, and all snags. In higher elevation spruce-fir forests, keep openings small (tree length in opening diameter) to avoid extensive wind damage.
14) Limit restoration or management activities such as prescribed burning, forest thinning, firewood removal, livestock grazing, and herbicide application to the non-breeding season. The nesting season is a critical period for the maintenance of bird populations, and some management activities can have serious consequences for breeding songbirds by destroying nests and nesting habitat or causing nest abandonment. When such actions are absolutely necessary during the breeding season, time disturbance to minimize impacts on nesting birds.
15) Protect or restore forests along streams, wide stream bottoms, and ravines, as they are crucial to both breeding and migratory birds.
16) Regardless of the motivation for altering forest habitat, retain all snags (standing dead trees). Snags increase bird density and diversity by providing perching, foraging, and nesting sites. They are an essential habitat component for primary and secondary cavity-nesting birds like woodpeckers, owls, bluebirds, and wrens.
17) Provide a complex forest floor, including downed logs, root wads, and a deep litter layer. Dead and down woody material on the forest floor provides a base for growth of new trees (“nurse logs”), harbors fungi that aid in nutrient cycling, and provides habitat for wildlife. Birds, like the Ovenbird, Townsend’s Solitaire, and Dark-eyed Junco, use downed logs, sticks, and leaf litter as nest sites, and nest in cavities found in root wads, stumps, and downed logs. Conserve forest floor complexity in managed forests (which often lack downed logs and a litter layer) by minimizing understory disturbance during harvest, retaining woody debris during harvest, felling additional trees if down woody debris has not been maintained at sufficient levels during earlier harvests, retaining root wads where they occur, and creating and retaining slash piles of various sizes during harvest.
18) Maintain deciduous components in coniferous forests, especially where they are declining. Encourage aspen regeneration. Deciduous trees provide fruits and foliage insects different than those of conifers, and have a higher density of cavities than conifers. Species that benefit from and are associated with deciduous trees in the canopy of conifer-dominated forests include the Warbling Vireo and Western Tanager.
19) Regulate ungulate grazing levels in aspen stands. Ungulates can cause injuries to overstory trees by stripping the bark and increasing their susceptibility to disease; heavy barking may indicate overutilization in the stand. Ungulates may also affect establishment of seedlings and stand development.
20) Maintain existing and reestablish pure and mixed stands of whitebark pine, dominated by trees that are resistant to blister rust.
21) In ponderosa pine forests, manage for both early (grass/forb and shrub/tree seedling) and late (mature and old growth) forest successional stages. Few wildlife species find their optimum habitats in the intermediate (pole-sapling and young) successional stages of ponderosa pine forests.
22) Create more open stand structures in ponderosa pine and Douglas-fir stands to improve and enhance the growth of large conifers and deciduous species and reduce vulnerability to insects, disease, and severe fire. These low elevation forests are often overly dense and contain numerous small trees. Use a combination of fire and mechanical treatments to reduce densities to levels found historically. Group selection, thinning from below, and shelterwood cuts, along with stand-maintaining fires, are all feasible options. A relatively open canopy in Douglas-fir and ponderosa pine forests would benefit species like the Wilson’s Warbler, Swainson’s Thrush, Warbling Vireo, Hairy Woodpecker, and Dark-eyed Junco.
23) Use prescribed fire or cutting to reduce the density of lodgepole pine forests. Thinning based on a diameter limit is more desirable for birds in lodgepole pine forests than thinning that retains uniform spacing; it results in a mosaic of habitat types similar to the results of some fires that enhance many desirable features of bird communities. Thin by diameter limit to fewer than 300 trees per acre (750 per hectare). This will permit ground cover to develop and facilitate stratification in the stand.
24) Protect the forest against exotic plants. When planting trees, select native species and avoid exotic species. Many exotic plants are vigorous species that can be established easily in many areas, but they out-compete native plants and dominate the areas they occupy, often have little value as wildlife habitat, and can quickly degrade existing native wildlife habitat. Monitor forested plots for nonnative, invasive plants, and devise a removal plan, if necessary. Control of any exotic plant species should involve both elimination and simultaneous introduction of a desirable competitor to minimize reinvasion.
25) Avoid attracting or supporting nonnative animal species. Nonnative animals can have a severely negative impact on songbirds. Invasive bird species such as European Starlings and House Sparrows often out-compete native birds for nest sites and have been known to destroy active nests and even kill nesting adults.
26) Where possible, restore or rehabilitate degraded and disturbed sites to native plant communities. Initiate actions to improve the quality of degraded forest habitat through appropriate management, particularly the use of natural disturbance regimes such as fire. Use planting, where appropriate, to reestablish conifers, especially where seed sources are gone. Use native species and local seed sources for restoration and rehabilitation.
27) Develop conservation partnerships between landowners, land managers, and private organizations to enhance the quality of forest habitat. Private landowner involvement is critical to the success of avian conservation efforts, and land management of individual ownerships should be coordinated with other ownerships and objectives whenever possible. While landowners need to derive income from the land, this can often be compatible with maintaining regional biological diversity, depending on how the land is used and what land management tools are employed. Identify the habitat needs of the birds in the area and the economic needs of the landowner so a baseline need is established. Important habitat on private land can be protected with conservation easements. In some cases, landowners can derive income from hunters, birders, and naturalists who visit the region.
28) While it is better for birds (and cats) if cats are kept indoors, have domestic “barn” cats spayed or neutered, keep pet food and food bowls indoors so predators like raccoons and feral cats do not have an additional food source, and never intentionally feed feral cats. Cats (even well fed domestic cats) can be devastating to local songbird populations. Natural predators, like owls and hawks, are very efficient at controlling rodent pests, even around human dwellings.
29) Regularly monitor birds to see how the management plan is working, and redirect efforts if necessary (with special emphasis for species that seem to be declining). Implement forest habitat monitoring programs to establish baseline data and identify changes in habitat quality (both positive and negative) through time. Use standardized methods to monitor the habitats and sensitive species in an area, before and at several-year intervals after treatments are applied, to aid in making proper land management decisions in the future.
Timber harvesting has sometimes been targeted as having negative effects on biodiversity, and when used indiscriminately, it can. Silvicultural practices alter landscape structure, forest age and structure, and create edges, all of which can adversely affect bird populations. However, timber harvest can be an effective tool for maintaining or restoring biodiversity and ecosystem health when used with both ecological and economic objectives in mind. Silvicultural techniques can remove high forest cover, thin trees, prepare the forest floor for tree regeneration, stimulate the growth of understory vegetation, decrease the incidence of disease and insects, maintain site-adapted species, and recycle nutrients. Innovative uses of silvicultural practices such as species selection, thinning, and biomass removal can go a long way in producing forests that are vigorous and healthy. Silvicultural practices at least partially replace natural disturbances in managed forests, and thus provide the means for producing desired changes in stand composition. Managed forests have the potential to provide suitable habitat for many bird species. These recommendations can help reduce the impacts of forestry on bird populations.
1) Provide a variety of forest habitat conditions and structural characteristics across the landscape to meet the habitat needs of most bird species. Design timber programs to provide the widest diversity of vegetation, allowing some forest plots to grow beyond their maximum productive age while cutting others to provide various stages of regenerating vegetation. However, do not maximize within-stand diversity at the expense of landscape or regional diversity. For example, selective cutting may produce high within-stand diversity, but an entire landscape of selectively cut uneven-aged forest would be lacking some Neotropical migratory birds.
2) Create more complex habitat conditions within logged areas by leaving some live and dead trees or by enhancing the growth of shrubs.
3) Manage for a diversity of tree species to provide habitat for birds that utilize a variety of tree species for foraging. For example, the Brown Creeper makes greater use of forest stands that are diverse in tree species composition. It may forage from a tree species as it occurs in mixed stands, but seldom forages in monotypic stands of the same species.
4) Retain a buffer zone in riparian areas where no timber harvesting and firewood cutting are allowed, to protect the stream channel and provide habitat for birds that depend on mature trees. Buffer zones that are at least 200 feet (60 m) wide can support avifauna similar to that of large forest tracts, while narrower buffer strips [e.g. 65 feet (20 m) wide] are more favorable to ubiquitous species than forest-dwelling species.
5) Maintain mature stands of trees adjacent to meadows to help species like the Olive-sided Flycatcher.
6) Retain snags (standing dead trees), dead-topped trees, and live trees with cavities under any cutting method. These increase bird density and diversity by providing perching, foraging, and nesting sites. They are an essential habitat component for primary and secondary cavity-nesting birds, like woodpeckers, bluebirds, and wrens, and enhance the number of insects available for food. In situations where some snags must be cut, retain larger snags rather than smaller ones. Snags eventually topple and become organic debris, so retain an abundance of mature trees to replace them over time.
7) Avoid post-fire salvage logging. Salvage and sanitation logging and debris disposal remove snags and snag recruits and reduce the amount of dead and down woody material that provide feeding and nesting sites for birds, especially post-fire dependent species like the Black-backed Woodpecker, Three-toed Woodpecker, and Hairy Woodpecker.
8) Maintain a shrubby understory in stands of trees adjacent to meadows and along stream courses to help species like the MacGillivray’s Warbler and Yellow Warbler.
9) Maintain some old growth forest for species that nest in large snags or live trees, feed largely on tree seeds, or require large acreages of continuous mature forest cover. The structure of old growth stands varies with forest type but can be characterized by multilayered canopies, large trees, large snags, large logs, and patchiness of overstory and understory vegetation. Leave at least 50 to 100 acres (20 to 40 ha) of old growth forest for every 1,000 acres (400 ha) that are cut. Lengthen rotation ages in even-aged systems and increase the proportion of larger trees in uneven-aged systems to encourage old growth characteristics in logged forests.
10) Use mechanical treatments in combination with prescribed fire to reduce the likelihood of stand-replacing fire and soil sterilization, particularly in low and mid elevation forests.
11) Maintain forest floor complexity, including downed logs, root wads, and a deep litter layer. Birds, like the Ovenbird, Townsend’s Solitaire, and Dark-eyed Junco, use downed logs, sticks, and leaf litter as nest sites; nest in the cavities of root wads, stumps, and downed logs; and eat insects that inhabit logs. To conserve forest floor complexity, implement the following strategies: 1) Protect old growth forests, which usually have deeper litter than younger forests. 2) Retain at least 12 large, uncharred logs per acre (5 per ha) and other woody debris during timber harvest. Particularly retain large logs—those greater than 12 inches (30 cm) in diameter at the large end and greater than 20 feet (6 m) long. 3) If woody debris has not been maintained at sufficient levels from earlier harvests, fell some additional trees to create this attribute. 4) Retain root wads where they occur. 5) Create and retain slash piles of various sizes. 6) Minimize understory disturbance. 7) Since most of a tree’s timber value is in the lower 1/3 of the bole, remove this portion and leave the top as a downed log.
12) Use a combination of even-aged and uneven-aged silvicultural systems across the landscape, with a significant portion of the stands managed for an uneven-aged structure, to create a mosaic of forest conditions and to benefit different species of birds. Uneven-aged management (e.g. single-tree selection and group selection) develops vertical complexity by maintaining trees in a variety of size classes, reduces horizontal complexity by not cutting entire stands, and minimizes edges and early successional stages. In contrast, even-aged management (e.g. clearcutting and shelterwood cuts) produces a monoculture of trees approximately the same size and height, increases horizontal complexity (spacing) by creating different successional stages between the various stands or cutting units, reduces vertical complexity of the vegetation, and creates edges where different successional stages meet. Although there is no forestry technique that will benefit all species, and the selection of a silvicultural system must be made on a stand-by-stand basis, uneven-aged management practices are often most suitable for healthy, mixed-aged stands, and often result in a greater number of bird species showing population increases than decreases compared with even-aged systems. However, do not maximize within-stand diversity at the expense of landscape or regional diversity; uneven-aged management may produce a well-developed vertical structure, but an entire landscape of selectively cut uneven-aged forest would be lacking some bird species. Similar bird species diversity can be maintained in both even- and uneven-aged management if the even-aged system is managed for a diversity of tree species, and if a range of stands of different ages (including mature and old growth) are maintained. Enhancing the vertical diversity of even-aged stands is also feasible, but generally more complex. In uneven-aged management systems, take care to prevent a shift in tree species composition.
13) Use a balance of the following cutting systems to create small openings for gap species, large openings for early successional forest migrants, and a balanced age-class distribution to maintain sufficient mature forest habitats.
a) Selective Cutting – Selective cutting of timber involves removing selected trees from a forest stand. This method prevents loss of soils, opens the forest floor to light which increases understory growth useful for cover and as a food source for many wildlife species, leaves much of the natural cover present when the operation is completed, and assures that there will be trees of many different ages within each stand.
i) Group Selection – In group selection cuts, small groups of trees are marked and removed. This method creates small, dispersed openings in forest stands. Group selection might be preferable as a smaller-scale alternative to clearcutting (e.g. to decrease the risk of loss from windthrow).
ii) Individual (or Single-tree) Selection – In single-tree selection cuts, individual trees are marked and cut. This method provides the least difference in horizontal stand structure, and favors species associated with uncut forests and those that require stands with a multi-storied structure. This method may be used where late successional or edge-sensitive bird species are desired.
b) Shelterwood Cutting – Shelterwood cutting involves the removal of all trees from an area except for several large trees that provide shade for developing seedlings. The large trees are removed a few years later, after the seedlings have become established. This method provides a variety of habitats attractive to species that forage in stands with widely spaced trees, and trees are still available for nesting and feeding until final harvest. The presence of mature, residual trees in shelterwood cuts maintains some of the characteristics of mature stands. Consequently, some species of birds generally associated with mature stands can be maintained after the first cutting in a shelterwood sequence.
c) Clearcutting – Clearcutting involves the removal of all trees from an area. Clearcuts or patch cuts that create small, dispersed openings in forests provide a mosaic of stands of different ages and species composition. The use of clearcuts is often criticized but, if used judiciously, clearcuts can provide habitat for early successional species and species like the Boreal Owl and Great Gray Owl that use small openings in the forest for foraging. Smaller clearcuts are more desirable for birds since small open areas favor species like raptors, and are not as detrimental to forest-dwelling and area-sensitive species as large cuts. The more forest habitat in a region, the larger clearcuts can be; determine the maximum size of clearcuts by considering the size of the management unit, the home range requirements of wildlife using the area, and natural disturbance regimes. Leave snags, woody debris, some slash piles, and pockets of vegetation in the form of islands or peninsulas to provide corridors for movement and refuge areas for wildlife.
14) Avoid fragmenting large contiguous forest tracts; these areas have the ability to support the largest number of forest-interior and area-sensitive birds. Although providing a variety of forest conditions is a goal, this should be accomplished at a landscape scale so that large contiguous forest tracts are not sacrificed. Most species have a minimum habitat size below which they cannot exist, so small patches of all ages and stand structures can result in a reduced number of species present in a region. Reserve some of the least fragmented areas from timber harvest.
15) Consider the regional and landscape context of a forest stand when planning silvicultural treatments at the forest-stand level. In forests that are surrounded by heavily urbanized or agricultural land, plan a lower impact use, such as uneven-aged harvesting or perhaps limited recreational activities, rather than a higher impact use, such as even-aged management. In situations where the surrounding landscape is primarily forested, it may be possible to increase timber production and/or use even-aged harvesting methods, given that large expanses of forest are not limited in the landscape. However, even in highly forested areas, large unbroken forest tracts should be managed carefully to avoid creating a checkerboard of smaller fragments.
16) Aggregate harvested areas within the forest into compact shapes to minimize adverse edge effects.
17) Avoid intensive forest management, which shortens early successional stages; eliminates the final stages by emphasizing stand regeneration, growth, and harvest; and may include brush control, tree planting, fertilization, and thinning—all of which tend to accelerate tree establishment and growth and reduce plant species diversity and structural complexity. Because succession is accelerated and maturity is brief, intensive forest management can decrease bird species diversity. Also, cavity-nesters are likely to decrease due to their requirements for decayed wood, particularly in industrial forests where intensive management favors faster-growing trees and eliminates decayed trees.
18) Avoid clearcutting in high elevation (e.g. spruce-fir) forests. Because regeneration can be slow and the stand initiation stage can last over a century, harvest just enough fir in mature subalpine forests to open the canopy, release suppressed fir saplings, and allow spruce seedlings to establish. Younger stands can be lightly thinned without disrupting processes, but older stands should be harvested by selective cutting methods, which appear to most closely simulate the natural dynamics of these forests. Group selection systems are easier to design and therefore may be preferable, especially in stands that are naturally patchy. All tree sizes, including some very large trees, should be represented in the post-harvest stand. Avoid harvesting the highest elevation [over 10,000 feet (3,000 m)] spruce-fir forests entirely; allow these high elevation areas to overmature and serve as reservoirs for spruce-fir forests at lower elevations.
19) In ponderosa pine forests, use silvicultural cuttings followed by compatible prescribed burning treatments to restore and maintain the old growth character. (Returning fire into dense stands or those with understory fuels could fatally damage overstory trees.) Use mechanical methods to break up the layer of abutting crowns in the overstory, leaving 10- to 30-foot (3- to 9-m) spaces between trees to reduce the potential for fire to spread through the upper canopy, and reduce the density of sapling and pole-sized trees. Use thinning, shelterwood cutting, and small clearcuts to create openings that enhance understory shrub, grass, and forb cover and to simulate the effects of a wildfire on small patches of seedlings or sapling-sized trees. Generally, between 1/6 and 2/3 of the available foliage of a ponderosa pine forest can be removed without detrimentally affecting the breeding bird community. The total basal area of a stand can be reduced by 15 to 50%; if removal is by uniform thinning, limit basal area removal to 30%. Remove no more than 45% of those trees with a dbh of 9 inches (23 cm) or greater, leaving a minimum of 32 trees per acre (79 per ha). Remove no more than 75% of those trees with a dbh between 6 and 9 inches (15 and 23 cm), leaving a minimum of 17 trees per acre (42 per ha). Remove 80% of the trees with a dbh between 3 and 6 inches (8 and 15 cm), leaving approximately 25 trees per acre (61 per ha). Conserve the old trees that still exist on the landscape and select trees for retention that will grow into an old growth condition in a reasonable amount of time. Leave groups of old growth trees intact to maintain the inherently clumpy nature of the stand. Plan similar cuttings at about 30-year intervals.
20) Periodically thin Douglas-fir stands from below to allow only short periods of crown closure, enhance growth rates of hardwoods and large conifers, enhance development of shrub cover, and benefit birds like the Wilson’s Warbler, Swainson’s Thrush, Warbling Vireo, and Hammond’s Flycatcher. Vary the thinning intensity through the stand to further enhance bird species richness.
21) In lodgepole pine stands, ensure that a seed source is present before applying mechanical treatments. Openings can be large where serotinous cones are present, but need to be small [25 acres (10 ha) or less] when nonserotinous cones are present. (Serotinous cones have scales that are sealed with resin. The seeds are stored in these cones for years until they are exposed to heat that melts the resin and allows the scales to open. This allows the tree to disperse the maximum amount of seeds when the conditions are optimum for germination immediately after a fire.)
22) Maintain and restore stands of deciduous trees (e.g. aspen) within coniferous systems to benefit birds like the Northern Goshawk, Warbling Vireo, Red-naped Sapsucker, and Western Tanager that use them for nesting and foraging. Deciduous trees provide fruits, seeds, mast, and foliage insects different than those of conifers, and have a higher density of cavities than conifers. In managed forests with a deciduous component, extend the rotation age to allow for development of canopy and sub-canopy gaps suitable for foraging habitat. Conduct conifer tree thinning where there is potential for understory development of deciduous trees, particularly in wet sites.
23) Avoid loss of or change in tree-species diversity and fitness by minimizing “high-grading” (the removal of only the most valuable species and the most structurally superior trees).
24) If slash must be burned following a harvest, broadcast burn rather than pile burn to reduce high temperature burns, which are destructive to soil organisms and small mammals.
25) Minimize mechanical treatments that increase susceptibility of the forest to invasion of exotic and noxious weeds and soil erosion.
26) Confine timber operations to noncontiguous drainages, as intervening ridges may reduce disturbance.
Prior to human settlement and fire suppression policies, fire was an important natural disturbance in most forest ecosystems. Wildfires stimulated renewal of plant cover by creating a mosaic of variable-aged vegetation, including all ages of conifers, herbaceous plants, and deciduous shrubs and trees. As a consequence of fire suppression, fire frequency has decreased and intensity has increased in many forests since the early 20th century. Fire suppression has altered the natural fire regime, resulting in the change in structure of many forests from open to closed stands. Although fires can be detrimental to forest birds during the early summer when eggs and nestlings might be destroyed, the absence of fire for a long period of time can also create problems when unburned forests become dense monocultures with inadequate reproduction of tree species and high fuel accumulation. Except for elevation differences, fire has been the most important factor influencing avian diversity in western forests, but understanding the effects of fire on birds is difficult because fires vary in intensity, duration, frequency, location, shape, and extent. However, birds evolved with forest fires, so it is reasonable to assume that bird species associated either directly with fires or with fire-maintained forest structures have been negatively affected by fire suppression. For example, the Olive-sided Flycatcher is often restricted to post-fire habitat and uses natural openings in the forest c