Before considering the role of fire ecology and fire management options, it is necessary to investigate specific fire requirements such as optimum fire intervals, fire frequency, fire season and type of fire, required to maintain biodiversity, management and social requirements. These characteristics and needs by region are summarised in examples below for some of the important biomes of temperate and boreal forests, and expanded in the attached Appendices.
2.1.1 Woodlands (Table 1a)
Characteristics
Most African woodlands are deciduous or semi-deciduous, but nearly all types contain a few evergreen species. The field layer is usually dominated by herbaceous tussock grasses, which are usually perennial. Annual grasses are predominant in certain transitional types, especially under the influence of heavy grazing. In most types there is an incomplete understorey of small trees, or large bushes of variable density and fire tolerance. The functional role of fire and fire impacts in woodlands are related to the availability of fuels in the grass layer. As a consequence of climate variability including, El Niņo / La Niņa, large inter-annual variability of fire extent has been observed in the semi-arid areas of Southern Africa Africa's woodlands. Drought and increasing grazing pressure lead to reduction of fuel loads available to be burned, and to a large variability in burning patterns (no fires or smaller burns). On the other side a wet year with reduced fire activity is often followed by an extreme fire year due to the higher availability of combustible materials.
Management Implications
The biggest problems, facing fire managers in woodlands, are to find ways to meet the ecological requirements and also to supply sufficient grazing. Too frequent fires will reduce the overstorey and degrade the system, while grazing pressure can disturb the ecological balance.
2.1.2 Natural Forests (Table 1a)
Characteristics
The temperate natural forests in Africa can be found within the Afro-montane forests, and occur in an archipelago-like pattern. Generally, non-degraded afro-montane forests do not readily burn due to their structure, separation from the litter layer, and higher fuel moistures. Crown fires in afro-montane forests are extremely rare. However, fire does play a significant role in controlling the extent of afro-montane forests.
Management Implications
Although climax forests are seldom exposed to major wildfires, transition zones are subject to disturbance that can systematically reduce these decreasing ecosystems. Protection measures are thus required where these occur.
2.1.3 Industrial Plantations (Table 1b)
Characteristics
Most even-aged Acacia, Eucalyptus and Pinus plantations have been established in Southern Africa, in areas where rainfall is exceeding 750 mm per year. As most species planted originate from fire-related natural ecosystems and are established mostly in dynamic montane or savannah grasslands with an equal need for regular fire occurrence to maintain biodiversity, fire is playing an important role, and total fire exclusion normally results in common wildfires. Fuel management is normally required in the form of slash burning after clearfelling, but sometimes prescribed burning under the trees is required to solve specific fuel accumulation or weed problems.
Management Implications
Where fire is excluded for too long, large plantation areas can be destroyed by wildfires. Regular fuel reduction is required, and special fire protection measures are needed to protect plantations in areas, which have a high fire hazard. More use of prescribed fire is also required to meet these challenges.
2.1.4 Fynbos and Sub-Alpine Moorlands (Table 1b)
Characteristics
The fynbos biome is a fire-prone shrubland in the wetter areas along the coast, and in the mountains of the southwestern part of South Africa. Fynbos, a vernacular term for fine-leaved shrubs, is vegetation-dominated by evergreen shrubs. Two other major vegetation types are included in the fynbos biome. These are renosterveld and strandveld. Renosterveld is also an evergreen, fire-prone shrubland. Strandveld is a mix of thickets made up of broad-leaved shrubs and small trees, fynbos, and renosterveld. These broad-leaved elements also occur in fire-excluding thickets and scrub forests, in summer rainfall regions. They are not flammable, have fleshy fruits (rare in fynbos) and exclude low intensity burns.
Management Implications
Burning of fynbos and other moorlands, at specific intervals and season, is required to maintain biodiversity. These prescribed fires have to be applied at regular intervals, as fire exclusion will result in high intensity wildfires and subsequent biodiversity disturbance.
2.1.5 Grasslands and Savannahs (Table 1c)
Characteristics
Two main types of grassland may be distinguished:
• Climatic climax grasslands where succession does not normally proceed beyond the grassland stage because the climate is too cold to permit the development of woody communities, even in the absence of fire.
• Fire climax grasslands where the climate will permit succession to proceed beyond the grassland stage into shrubland or forest, but which are maintained as grassland by biotic factors such as fire and grazing. These grasslands are also referred to as “secondary” grasslands, or “false” grasslands.
Management Implications
Fire managers are faced with the challenge to satisfy ecological requirements for savannah and grassland, for specific burning rotations, fire intensities and burning seasons. They need to provide grazing resources in rural and agricultural areas and, in certain districts, they face increased population pressure.
2.1.6 Kalahari Grasslands and Shrub lands (Table 1c)
Characteristics
The grasslands and shrub lands of the southern Kalahari cover a major portion of Botswana (excluding the Okavango Delta, Chobe and Gabarone areas) and extend into parts of Namibia and South Africa. The Kalahari is a stark landscape dominated by sand dunes and plains, pans, and dry fossil riverbeds. There is a lack of surface water, as sand transports water to deep aquifers. Yet, fire is a significant part of this landscape, and under favourable conditions it can burn large tracts of land.
Management Implications
Irregular fire occurrence can lead to site degradation, and fire exclusion for longer periods is sometimes required, needing selective fire protection measures.
2.1.7 Fire Management in Nature Reserves, National Parks and other Protected Areas
Characteristics
This category covers all African ecosystems, each having its own fire-related ecological requirements. However, in the absence of urban-interface problems, forestry, agricultural and rural population needs, the emphasis can fall on ecological expects, with the exception of fire protection along strategic boundaries and roads. It is particularly in grassland and savannah-based nature reserves, with regular lightning occurrence and dense animal populations, that special attention is regularly required to check policy application, and for any disturbance of fire mosaics, as a result of too frequent or too little fire.
Management Implications
Although in many cases the natural occurrence of fire, as a result of e.g. lightning, should be encouraged, selective use of prescribed burning may still be required to adjust for problems introduced by man, such as fences and other obstacles that can produce a lack of escape routes for animals. This might lead to some significant adjustments of fire-related policies.
2.2.1 Evergreen Mixed and Thorn Forests (Table 2a)
Characteristics
Maintenance of biodiversity is dependent on fire intensity experienced and burning intervals, and these biomes are susceptible to repeated high intensity fires, which can degrade sites, and which can lead to a decrease in grazing provision. Transition zones are most vulnerable. Fire damage to Araucaria and Nothofagus forests is dependent on the degree of disturbance. Small patches are particularly vulnerable. High intensity fires in Thorn Tree forests open up crown canopy and increase grass cover.
Management Implications
Fire protection, particularly along forest edges, can lead to improved biodiversity maintenance and sustainable grazing, provided this goes hand in hand with selective weed control where required. In Thorn forests, selective use of prescribed fire may be necessary for ecological reasons, as well as for biodiversity maintenance.
2.2.2 Industrial Plantations (Table 2b)
Characteristics
Most even-aged Eucalyptus and Pinus plantations, situated in the higher rainfall regions of South America, originate from fire-related natural ecosystems and are established in grasslands, woodlands and old forest land, which also needs regular fire occurrence to maintain biodiversity. Fire is thus playing an important role in these areas, and total fire exclusion normally results in regular wildfires. Selective fuel management is normally required in the form of slash burning after clearfelling, but sometimes prescribed burning under the trees is also required, to solve specific fuel accumulation or weed problems.
Management Implications
Where fire is excluded for too long, large plantation areas can be destroyed by wildfires. Regular fuel reduction is required, and special fire protection measures are needed to protect plantations in areas with a high fire hazard. More use of prescribed fire is also required to meet these challenges.
2.2.3 Sclerophyllous and Semi-Desert Scrub (Tables 2b and 2c)
Characteristics
Although most of times seldom reaching a wildfire climax, particularly in the case of Semi-Desert Scrub, some Sclerophyllous Scrub needs fire at specific intervals to maintain an ecological balance, depending on the climatic region where these biomes are situated. In the latter, uncontrolled fire may favour alien vegetation in some regions, and also disturb biodiversity.
Management Implications
Selective prescribed burning may be required in Sclerophyllous Scrub in the higher rainfall regions, while the selective use of exotic weed removal may also have to be implemented where needed, to maintain biodiversity.
2.2.4 Pampas and other Grasslands (Table 2c)
Characteristics
The Pampas occur on the lower altitude parts of the central and eastern parts of temperate South America, and prescribed fire requirements mainly depend on grazing intensity, type of grassland and climate. Fire history, biodiversity requirements, rainfall pattern, tree and bush regeneration requirements also influence successional development of the grassland.
Management Implications
Prescribed burning application should be considered by means of quantifying grazing intensity, fire history and successional needs. The correct prescribed fire application will ensure that the risk of wildfires is reduced, optimum grazing potential is provided, and the uncontrolled promotion of undesired species in restricted.
2.2.5 Fire Management in Nature Reserves, National Parks and other Protected Areas
Characteristics
This category covers most temperate ecosystems in South America, each having its own fire-related ecological requirements. However, in the absence of urban-interface problems, forestry, agricultural and rural population needs, the emphasis can fall on ecological expects, with the exception of fire protection along strategic lines.
Management Implications
Although in many cases the natural occurrence of fire as a result of e.g. lightning, should be encouraged, selective use of prescribed burning may still be required to adjust for problems introduced by man, such as fences and other obstacles, that can produce a lack of escape routes for animals, where applicable. This might lead to some significant adjustments of fire-related policies. However, in most National Parks, the uninterrupted allowance of natural fire will provide the best ecological environment.
2.3.1 Evergreen and Sclerophyllous Forests (Table 3a)
Characteristics
In forest other than Eucalyptus forests, such as in the Nothofagus forests of Tasmania, fire may be a rare occurrence, but disturbance in the form of exploitation or grazing may create abnormal fuel levels and other damage to these forests, which may result in forest degradation. The protection of forest transition zones is important to avoid this.
Management Implications
Lack of forest edge protection may result in biodiversity loss and site degradation. Exploitation and other disturbance of these forests will also lead to abnormal fuel creation and a subsequent increase in fire hazard.
2.3.2 Industrial Plantations (Table 3b)
Characteristics
Most even-aged Pinus plantations, situated in the higher rainfall regions of Australia and New Zealand, originate from fire-related natural ecosystems and are established in grasslands, woodlands and old forest land, which also needs regular fire occurrence to maintain biodiversity. Fire is thus playing an important role in these areas, and total fire exclusion normally results in regular wildfires. Selective fuel management is normally required in the form of slash burning after clearfelling, but sometimes prescribed burning under the trees is required to solve specific fuel accumulation or weed problems.
Management Implications
Where fire is excluded for too long, large plantation areas can be destroyed by wildfires, particularly where species other than Pinus radiata are established. Selective fuel reduction is in most cases required, and special fire protection measures are needed to protect plantations in areas with a high fire hazard. More use of prescribed fire is also required to meet these challenges.
2.3.3 Scrubland in Lower Rainfall Regions (Tables 3b and 3c)
Characteristics
Normally only irregular fire is experienced in these biomes, the interval of occurrence depending on climatic factors. In Hummock Grasslands, wind-driven fires are more commonly experienced. If wildfires are too frequent, site degradation is possible.
Management Implications
Where fires are experienced more frequently than ecologically required, some fire protection measures may be required, to avoid site degradation.
2.3.4 Tussock Grassland
Characteristics
Tussock grasslands cover a substantial part of particular Australia. These grasslands normally require fire at various intervals, depending on the climate, grazing potential and grass type. Wildfires sometimes present a high risk, which can lead to serious loss of grazing potential. A suitable wildfire climax should be maintained, depending on the grazing intensity experienced.
Management Implications
Prescribed fire should be applied at the correct intervals, to promote optimum grass and tree/bush regeneration. Grazing potential will to a large extend determine the need for fire application, but species composition and climate will also contribute towards specific fire needs.
2.3.5 Fire Management in Nature Reserves, National Parks and other Protected Areas
Characteristics
This category covers most temperate ecosystems in Australia, Tasmania and New Zealand, each having its own fire-related ecological needs. Specific fire requirements, for specific ecosystem goals normally apply, including the need for fire protection.
Management Implications
Although in many cases the natural occurrence of fire as a result of e.g. lightning should be encouraged, selective use of prescribed burning may still be required, to adjust for problems introduced by man.
With a total land mass of 921.5 million hectares, of which almost half (417.6 million ha) is covered by temperate and boreal forests, Canada is a vast country, largely dependent economically on forestry and forest industry. Forests considered capable of producing commercial forest products cover 234.5 million hectares across the country, primarily in the temperate and southern boreal forest regions, but only 119 million hectares are currently managed for timber production, with the remainder of the commercial forest being set aside for other purposes. Provincial governments own 71% of Canada’s forest land, and are responsible for all aspects of forest management on this land base, including forest fire management. The federal government has ownership of 23% of the forested land, primarily in the Northwest and Yukon Territories, while private individuals, communities, and companies own 6%.
Individual provinces and territories have, over much of the past century, developed sophisticated fire management programs aimed at protecting human life and property, while maintaining the forest resource for public and commercial use. Fire management resources are shared between provincial/territorial agencies as required, and between Canada and the United States on occasion. Between 8,000 and 10,000 fires occur annually across Canada, but the area burned each year is highly episodic, varying by more than an order of magnitude, from 500,000 ha in low years to 7,500,000 ha in extreme years. On average, a total of $500 million is spent annually on fire management activities in Canada.
Due to aggressive suppression activities, only 3% of Canadian fires grow larger than 200 hectares in size, but these fires account for 97% of the area burned. The distribution of large fires is highly variable across Canada, due to differences in fire weather severity and forest fuel types, and to varying levels of fire suppression throughout the country. The fact that large parts of the Canadian forest landscape are essentially unprotected - fire being allowed to burn naturally when not a threat to values-at-risk such as communities, recreation, or forest industry interests, is a major contributor to large areas burned in Canada. An evaluation of fire activity across Canada is best accomplished at the ecozone scale. Forest fires are common within 11 ecozones across Canada (excluding the various Arctic ecozones, and the prairies), but their impact is highly variable. Due to distinct east-west differences in fire weather and fire regimes, the Taiga and Boreal Shield Ecozones are often subdivided. 39 years of fire data (1959-1997) was used to determine both the average annual area burned and the % annual area burned (PAAB - a function of both fire activity and ecozone size) for each ecozone.
2.4.1 Taiga Region
Taiga ecozones stretch across Canada from the northern Yukon through the Northwest Territories, northern Manitoba, and northern Quebec, and represent the transition zone between Arctic tundra and the Canadian boreal forest. This region consists primarily of non-commercial forest, with numerous aboriginal communities and natural resource extraction industries (primarily mining, and fossil fuel exploration).
Taiga Cordillera Ecozone
Located in the northern Yukon and northwestern Northwest Territories, this ecozone is mountainous with sparse forest cover, and is largely unpopulated. Vegetation is primarily comprised of arctic tundra, alpine tundra, and taiga species of shrubs, lichens and dwarf spruce and birch. Lightning fires dominate in this ecozone, burning over an average of ~20,000 ha annually, with a Percent Annual Area Burned (PAAB) of 0.184%. Suppression activity is minimal.
Taiga Plains Ecozone
Covering the southwestern region of the Northwest Territories, northeastern British Columbia, and northern Alberta, this ecozone is characterized by slow growing conifer forest, primarily black spruce. Population density is quite low, and lightning fires dominate. Fires are suppressed only when communities are threatened, and cover an average of ~366,000 ha annually (PAAB = 0.701%).
Taiga Shield Ecozone
This ecozone, heavily glaciated during the last Ice Age, stretching across Canada from the Northwest Territories through northern Manitoba, Ontario, and Quebec, is largely unpopulated. The Taiga Shield Ecozone can be subdivided into two sub-ecozones, separated by Hudson Bay, based primarily on distinctly different fire regimes due to variation in fire weather and climate.
Taiga Shield West Sub-Ecozone
Occupying portions on northern Manitoba, Saskatchewan, Alberta, and the southeastern Northwest Territories, this ecozone is dominated by dwarf conifer stands and lichen woodlands. Lightning fires predominate and population is low and centred around mineral and resource exploration. An average of ~243,000 ha burn annually in this ecozone, since a large proportion of fires are allowed to burn naturally, with a PAAB of 0.767%.
Taiga Shield East Sub-Ecozone
Covering central Quebec and Labrador, this ecozone has many features similar to the Taiga Shield West Ecozone, but a less continental climate, and generally less severe fire weather conditions. Population is low and scattered, and lightning fires dominate. Most fires are allowed to burn naturally. The result is an average annual area burned of ~117,000 ha (0.255% PAAB).
Boreal Region
Boreal ecozones stretch completely across Canada, representing a transition zone between taiga to the north and montane forests (British Columbia), grasslands (Alberta, Saskatchewan, and Manitoba) and temperate mixed wood forests (Ontario and Maritime provinces) to the south. It is in the boreal region, with its growing accessibility and natural resource-based development, where the full range of fire suppression options are utilized. The southern boreal, particularly in Eastern Canada, supports a fully developed forest industry, and active fire suppression is paramount. In northern boreal regions, however, fires are fought based on values-at-risk, with management decisions being made based on protecting communities or property versus permitting fires to burn naturally.
Boreal Cordillera Ecozone
Located in northern British Columbia and the southern Yukon, this ecozone is quite mountainous. Vegetation is often discontinuous and ranges from grasslands to open and closed cover forests. Population levels are low and protection efforts are modest and selective. Lightning fires predominate, contributing to an average annual area burned of ~ 106,000 ha (PAAB is 0.385%).
Boreal Plains Ecozone
This ecozone stretches from northeastern British Columbia across central Alberta and Saskatchewan to southeastern Manitoba, and was not glaciated during the last Ice Age. The region is essentially 100% developed and fire protection is maximized. Despite this level of protection, fire climate is often extreme, and large fires are common. The standard boreal species mix of spruce, pine, poplar, aspen and birch predominates. The average annual area burned is ~231,000 hectares (PAAB is 0.399%)
Hudson Plains Ecozone
This ecozone is largely centred in Ontario immediately south of Hudson Bay, but extends a small distance west into northern Manitoba and east into northern Quebec. The area contains extensive poorly drained wetlands dominated by a cold continental climate, which prevents the development of very large fires. Population levels are very low. The result is an ecozone with a low level of fire activity (annual average area burned of ~44,000 hectares (PAAB of 0.058%).
Boreal Shield Ecozone
This ecozone, the largest in Canada, extends from northern Saskatchewan through much of Manitoba, Ontario and Quebec to include Newfoundland. Also glaciated 10,000 years ago, but now over 80% forested, this ecozone is dominated by closed conifer stands of spruce, pine and fir, with some deciduous species such as aspen, poplar and birch. Much of the boreal shield ecozone zone is managed for resource extraction, particularly timber production, and has become much more accessible in recent decades. This is particularly true in the southern regions of the ecozone, while northern areas remain much less developed. The Boreal Shield Ecozone can also be subdivided into two distinct sub-ecozones with different fire regimes, which are separated by the Hudson Plains Ecozone in northern Ontario.
Boreal Shield West Sub-Ecozone
This sub-ecozone, covering northern Saskatchewan, central Manitoba and northwestern Ontario, has a strong continental climate and major fire activity. Although much of the region is managed forest, and population levels are moderate, there are still some northern areas where fire is not actively suppressed. As a result, the average annual area burned is ~516,000 hectares (0.769% PAAB)
Boreal Shield East Sub-Ecozone
Occupying much of the central and southern regions of Ontario and Quebec, and all of Newfoundland, this sub-ecozone is basically fully managed forest in which fire suppression activities are extensive and quite successful. The area is heavily populated by boreal standards. In addition the fire climate in this area of Canada is not as extreme as in the western shield region. The result is a much smaller average annual area burned (~155,000 hectares) and PAAB (0.167%).
Montane Cordillera Ecozone
Most of southern British Columbia and a portion of southwestern British Columbia are contained within this ecozone. It is the most diverse of all Canadian ecozones, ranging from alpine tundra to dense conifer forests. The climate can be quite dry in valleys due to mountainous rain shadow effects. Vegetative cover is extremely diverse and commercial forest operations are extensive, along with mining, energy production, and tourism. Protection efforts attempt to exclude fire across the complete ecozone, and are largely successful, but extreme fire danger conditions frequently create a challenge. The average annual area burned is ~24,000 ha (PAAB is 0.058%).
Pacific Maritime Ecozone
This ecozone covers the mainland Pacific coast and offshore islands of British Columbia. The climate is humid maritime with generally high precipitation levels. The area is heavily populated with an extensive forest industry. Protection levels are high, but the generally moist climate precludes much fire activity. The average annual area burned is only ~2000 ha with a PAAB of 0.013%.
Atlantic Maritime Ecozone
Covering the Maritime Provinces of New Brunswick, Nova Scotia, and Prince Edward Island, and a portion of southern Quebec, this ecozone is relatively small but highly populated with extensive forestry, mining, farming and fisheries industries. Forests are generally dominated by mixed stands of conifer and deciduous trees. Full fire suppression is practiced in this region, and this factor, in combination of generally modest fire danger conditions, results in a very low average annual area burned (~4200 ha) with a PAAB of 0.024%.
Mixedwood Plains
This small ecozone, located almost totally in southern Ontario, has been largely deforested over the past two centuries. Pockets of mixedwood stands exist, but deciduous species dominate. This is the most populated region of Canada, with all fires receiving a prompt response. This, in combination with a lack of fire-prone forest, results in the lowest fire activity in forested Canadian ecozones. The average annual area burned is ~190 ha with a PAAB of only 0.006%.
