The chapter has seven parts:
Broad variations in climate, soils, elevation, latitude and topography throughout the province combine to produce a diversity of plant communities for grazing, including grassland, wetland, forest land, subalpine and alpine.[39] Eleven of B.C.’s 14 biogeoclimatic zones are used for grazing.
Forest land is particularly important — totalling nearly 80% of the provincial Crown range resource. Forested range covers about 11 million ha, most of which is Crown land administered by the Ministry of Forests and is comprised of forage crops, improved pasture, native range and community pastures. Grasslands cover about 1.2 million ha, most of which are privately owned. Considerable information is available describing grassland and low-elevation forested zones in the southern Interior,[40] but considerably less is known about mid- to high-elevation forests, northern forested zones and community pastures. Crown range accounts for about 85% of the area used for grazing in the province. Over most of this area native grasses and forbs are the primary source of feed, with little or no grain supplementation.
The Ministry of Forests range inventory is based on forest cover information and ecological information from the biogeoclimatic ecosystem classification system. The range inventory program collects and analyzes resource information required for planning and managing Crown rangelands. The program has three components:
Each of these is described in more detail in the following sections.
Range cultural information is stored in digital files in the ministry’s Resource Inventory Branch database.
Districts and regions are responsible for preparing range cultural information according to specified standards for each cultural feature. Detailed information about range improvements on Crown land is recorded by district range staff using a computer system called the Range Improvement System. The Range Manual provides a complete description of range improvements.[42]
Digitized mapping is complete for 90% of the area of the province where domestic livestock grazing occurs. Range mapping has been completed in the Cariboo, Kamloops and Nelson Forest Regions, and maps are updated at appropriate intervals. Mapping in other forest regions is being completed. Digital maps are used to produce provincial output maps and associated reports. Range information updates are coordinated with the forest inventory update schedule.
GRTs group forest types into broadly similar vegetation types where similar range management considerations could apply. They are defined using ecologically-based grouping criteria so that the resulting vegetation groupings are relevant for range planning purposes. GRT grouping criteria can vary from one planning exercise or geographical area to another, depending upon a number of factors, including scale at which the GRTs are to be used and the specific area where they will be applied. For this reason, thay are not uniformly defined in the way that inventory groups are.
The generality of the GRT varies with the size of the area undergoing analysis. For large areas (e.g., the province), very broad or general criteria are used. These broad GRTS are usually characterized by broad vegetation types (e.g., grasslands, timbered range). For smaller areas, where more detailed range unit planning is required, more specific criteria are developed and applied, based on such things as productivity or accessibility characteristics. This usually results in the differentiation of some broad GRTS into more narrowly defined units.
Table 4.1 lists B.C.’s 17 GRTs and the range inventory strata or group of forest cover attributes, of which each is comprised.
The GRT definitions shown in Table 4.1 are very similar to those reported in the 1984 Resource Analysis. Each of the major GRTs and their significance for forage production is described below.
Water is a critical element on these sites. Annual water supply from precipitation is approximately 300 millimetres of rainfall and 100 centimetres of snowfall. The rich organic soils which underlie these grasslands are very susceptible to erosion following disturbance.
The lower elevation open rangelands are particularly important to the ranching industry for livestock grazing during the spring and fall. These low elevation sites must be managed carefully. They correspond to classes 1 and 2 wildlife habitat and are susceptible to degradation by over-grazing from livestock and wildlife.
Wetlands are used for summer grazing when soil moisture is low enough to allow livestock onto the sites. Typically these areas are small but highly productive. Forage production ranges from 1500 kilograms to over 5000 kilograms of air-dry forage per hectare.
Water is not as critical an element on these sites as it is in open range areas. Typically, annual rainfall is about 600 millimetres and snowfall about 400 centimetres. The soil on these sites is very sensitive to erosion because it is thin and the topography is usually rugged. The short growing season limits the ability of alpine range to produce forage and recover from defoliation.
The grass-sedge communities of lower elevation alpine range provide an important source of late summer forage for livestock. These areas are fairly productive but must be carefully managed because over-grazing will quickly lead to soil erosion.
Similar to open range, water is scarce and limits forage production. Rainfall is approximately 300 millimetres annually and snowfall about 100 centimetres annually.
This range type is important to both the ranching industry and wildlife. Primary use by wildlife occurs during the winter, early spring and late fall. These sites can produce high quality forage, but because they are so susceptible to degradation, grazing must be carefully managed.
Water supply is a critical element in these areas. Precipitation is normally near 600 millimetres per year and snowfall about 300 centimetres.
This range type is used primarily as summer range. Production is good, averaging from 250 kilograms to 1300 kilograms of air-dry forage per hectare, but forage quality declines rapidly as the summer progresses. Adjacent dense forests provide good bedding cover. This range type is moderately sensitive to disturbance.
Water supply, particularly in areas located within the Engelmann Spruce–Subalpine Fir zone, is not as great a limiting factor as it is in the dry forest type.
Summer grazing is particularly important on these sites. Forage production varies from near zero at high stand density to about 500 kilograms of air-dry forage per hectare at lower stand density. In some areas, stands are burned or thinned to increase their productivity.
Water supply is not a critical element on these sites since annual rainfall averages about 700 millimetres and annual snowfall about 500 centimetres.
Clearcuts are used extensively for summer grazing, and dense lodgepole pine stands usually provide good browse. Because of the competition for browse, the potential for conflicts between livestock and wildlife on these sites is substantial.
These locations may be classified under the forest inventory system as either non-productive, disturbed or not-satisfactorily-restocked to a forest crop. The sites vary widely in plant species presence and soil moisture and their value as livestock grazing range varies accordingly. For example, in the Peace River area these sites are heavily used by livestock, whereas on the mid-coast transitional areas are non-commercial or non-productive types with limited or no opportunity for grazing.
Figure 4.1 shows the GRTs for the Cariboo Forest Region. This region is dominated by lodgepole pine forest range and dry forest range. The northeastern portion of the region contains a large area of wet forest range and some alpine range. A significant component of deciduous forest range is found at lower elevations. Open range is concentrated along the Fraser Canyon and surrounding Alexis Creek to the northwest. Private land is usually low-elevation land and frequently includes deciduous forests.
Figure 4.2 shows the GRTs for the Kamloops Forest Region. Alienated land dominates the lower elevations of this region. Bordering much of the alienated land is dry forest range. A scattering of open range and ponderosa pine forest range also abuts the alienated land, especially in the Merritt Forest District. Wet forest range predominates in the eastern portion of this region and borders the Vancouver Forest Region to the west.
Figure 4.3 shows the GRTs for the Nelson Forest Region. At lower elevations the alienated land is bordered by mainly dry forest range and occasionally, in the Rocky Mountain Trench, by open range and ponderosa pine forest range. Wet forest range and lodgepole pine forest range are distributed throughout this forest region. GRTs are mainly based on leading tree species by volume. GRTs in the Nelson Forest Region often contain several other dominant species that are difficult to further subdivide into specific range types.
Figure 4.4 shows the GRTs for the Prince George Forest Region. This region has two distinct areas of range. One area includes the Rocky Mountains and the area to the southwest. The southwest portion of this area is dominated by wet forest range and lodgepole pine forest range; the northern portion also contains a significant amount of alpine forest range. The second area, located northeast of the Rocky Mountains, contains a significant amount of alienated land in the Peace River and large areas of deciduous forest range. Wet forest range, which includes black spruce, dominates the extreme northeast.
Figure 4.5 shows the GRTs for the Prince Rupert Forest Region. This region is dominated by wet forest range and alpine forest range. The area surrounding Smithers in the southeastern section of the region contains lodgepole pine forest range and significant alienated land.
Figure 4.6 shows the GRTs for the Vancouver Forest Region. This region is dominated by wet forest range, alpine forest range and alienated land. There is a small area of dry and deciduous forest along the Fraser Canyon and eastern Vancouver Island. The region has very few (about 2200) AUMs.
Range inventories are currently based on a classification of GRTs. This classification has limitations because a single GRT often contains many different ecosystems, with different resource values and responses to management activities. Preventing or correcting range problems, such as the decline in grazing-sensitive species or the incursion of noxious weeds, has been difficult without an ecologically-based classification system. Knowledge of site potential and ecological limits of plant species is prerequisite to better management.
