Forest Landscape Restoration After Fires

Transcription

1 47 Forest Landscape Restoration After Fires Peter Moore Key Points to Retain The fire situation needs to be analysed as well as possible with available data to support decisions about restoration. Identifying and engaging with those who light fires, have fire responsibilities, or are impacted by fires is critical. Protecting the restoration site from fire until species being used can withstand fire, if it is a natural disturbance, is essential. 1. Background and Explanation of the Issue The need to restore a landscape for its conservation objectives after fire has impacted may appear to be clear and is often obvious. However, without an understanding of the causes of the fire and its role in the ecosystem, then what is clear and obvious may be totally misunderstood Short Historical Account of Fire Throughout history there have been large fires that have damaged human assets and impinged on human perceptions. Some of these events have framed human response to fire. They continue to do so Portugal, Spain, Los Angeles, and eastern Australia in 2003 and the Great Borneo fires of are examples. Fire is one of the oldest tools known to humans. It has been used as a management technique in land clearance and preparation for crops for centuries. For the thousands of farmers, ranchers, and plantation owners on the edge of the agriculture frontier pushing into forests, fire is the obvious mechanism. It is normally the least expensive and most effective way of clearing vegetation and of temporarily fertilising nutrient poor soils. In most cases the deliberate fire use we see in developing nations is an echo of what occurred historically in what are now developed countries such as the northeast United States in the 1700s where fire was used to clear forest and convert land to other uses, initially agriculture Short Introduction to Fire in the Landscape Fire is a prominent disturbance factor in most vegetation zones throughout the world, the most ubiquitous after human urban and agricultural activities. 399 In many ecosystems fire is a natural, essential, and ecologically significant force, organising physical and biological attributes, shaping landscape diversity, and influencing the global carbon cycle. Fire has been part of the landscape since Mesozoic times. The combination of fires and grasses helped create the savannahs and open plains and provided 399 Bond and van Wilgen,

2 332 P. Moore 400 Singh et al, Luke and McArthur, Gill, Joint Research Center of the European Commission, Cochrane, opportunities for the proliferation of a wide range of grazing animals. For example, Australian vegetation has been subject to the influence of fire, by indigenous (aboriginal) burning and then by the burning practices of European settlers, 400 over a wide range of environments. 401 This pervasive fire presence has influenced a transformation in Australia to the current flora that are considered both fire tolerant and also in many cases are fire adapted requiring fire for regeneration and life-cycle stages. 402 This same story can be told for many ecosystems. Forest fires occur because of either anthropological or natural causes. Lightning is the most common natural cause of fire. The majority of fires around the globe are caused by human activity. The extent and timing of fires differs between natural ignitions and fires by people, those by people generally being smaller. While it is difficult to compile precise figures, in the year 2000, a year that was not strongly associated with bad fires, the European Community s Global Burned Area Assessment Project identified 251,000,000 hectares of burn scars worldwide. 403 In fire-sensitive ecosystems fire causes severe damage. One widely known example, tropical rainforest ecosystems, are characterised by high levels of humidity and moisture, they do not normally burn and are extremely prone to severe fire damage when they do. Damage from fire can be long lasting on a tropical forest ecosystem. 404 Just as too much fire can cause problems, so can too little. Many fires in boreal forests are caused naturally by lightning. However, some countries, such as the United States, have had a policy of suppressing most fires that threaten to grow out of control. Under these circumstances fire suppression can lead to unnatural conditions in which forests, which have historically experienced small intermittent fires, no longer burn. Fire suppression can lead to a buildup of dead biomass, and altered tree species composition, so when a fire does start, instead of being relatively small, it is much more intense and on a large scale. This conclusion seems to have been reinforced almost annually in the United States since Understanding the reason fire is introduced to or suppressed from a landscape is critical. Should the reason not be addressed, restoring the landscape will be difficult and ultimately futile Brief Description of Fire Impacts Fire has played, and will continue to play, a major role in shaping ecosystems throughout the world. Fires can produce local extinctions of species, alter species composition and successional stages, and bring about substantial changes in ecosystem functioning (including soils and hydrology). In almost all forest ecosystems throughout the world, humans have altered the natural fire regimes by changing the frequency and intensity of fires. People have excluded or suppressed fires and changed the nature of the landscape so that a naturally occurring fire will not behave in the same way it would have done in the absence of human impact. The interrelationship between humans, fire, and forests is a complex one and has been the subject of many studies and reports. 405 In some ecosystems, however, fire is an uncommon or even unnatural process that severely damages vegetation and can lead to long-term degradation. Such fire-sensitive ecosystems, particularly in the tropics, are becoming increasingly vulnerable to fire due to growing population, economic, and land-use pressures. 406 In most developed nations the process of natural area loss and degradation has been slowed or reversed. Public responses to fire, generally viewing fire as negative and destructive, have led to a focus on fire suppression.this in its turn has had profound effects on vegetation patterns Jackson and Moore, Goldammer, Bond and van Wilgen, 1996.

3 47. Forest Landscape Restoration After Fires The Fire Impact Cycle The key variables of fire regimes are the following: Season in which the fire takes place The extent and patchiness of the fire The fire intensity either too low or too high can create both negative and positive effects Fire frequency too little time or too much time between fires can be negative The cycle of fire impact hinges around these regime characteristics. The impact of a fire will be positive or negative depending on the degree to which the fire conforms to a regime that the landscape can accommodate. Wrong season, too small or too large, too high or too low an intensity, and too often or not often enough and the cycle may become out of balance leading to negative impacts. If the cycle remains too far out of balance with the landscape, then fire may lead to a long-term alteration to the ecosystem. These characteristics of fire can create significant impacts if they hinder the ecosystem s capacity to absorb and harness their influence. So fire may not be intrinsically positive or negative but always has the potential to have a profound impact with potentially long-term effects. Fire is of specific concern where a particular landscape represents a significant or unique ecosystem of global importance. Under such circumstances it becomes even more important to evaluate and manage the role of fire to sustain those values. Changes in the fire regime that fall outside the capacity of the landscape to contain them will possibly influence a cycle of impact that, depending on perspective, will be considered either negative or positive The Questions of Restoration After Fire Why and When Restoring? The natural and human created role of fires in landscapes sets up the context for decisions about restoring landscapes. The decisions need to be based very clearly on an understanding of the role of fire in a particular landscape. This in turn needs to be informed about the fire presence in the landscape How many? How often? How large? How intense? What season? Also, the cause of fire in the landscape must be identified. Fires can be thought of as having the following characteristics: A source the ignition means, such as lightning, matches, metal striking rocks A cause the agent that lit the fire, such as farmer, tourist, or land-clearing contractor A motivation the reason the fire was lit, such as negligence, livelihood, or accident Armed with good knowledge of the fire characteristics, the reasons underlying the origin of the fire, and understanding the role of fire in a particular landscape, the following restoration questions can be answered: Is restoration likely to be successful or useful? Can/should the same species be used for restoration? Will restoration have to be staged, with initial work creating the opportunities for later efforts? Fire as a Natural Disturbance The need for restoration will rest on the extent to which the fire regime is out of step with what the landscape can accommodate. Actions might include the following: Controlling Fire to Bring It within the Regime that the Landscape can Absorb Reducing ignition sources Managing fuels Suppressing fires that do not meet the requirements for the landscape (a very difficult decision to make 408 ) 408 It is far easier to suppress all fires than to make such a decision. Human assets may be impacted, perceptions of the role of fire in the landscape will differ, and hence the fires that should or should not be suppressed will vary. Conflict is likely, particularly when damage is caused.

4 334 P. Moore Replanting with local species to overcome losses, which will normally have to include protecting the replanting from fire that is inconsistent with the landscape fire regime Removing species that have been favoured by inappropriate fire or that have invaded, including the use of fire in some cases Undertaking physical works to protect, restore, or limit the degradation of the landscape features such as soil and drainage lines Introducing Fire to Reestablish a Fire Regime Consistent with the Landscape Setting fires under prescribed conditions consistent with the fire regime Measuring and if necessary managing fuels Suppressing fires that do not meet the requirements for the landscape Removing species that have been favoured by inappropriate fire or that have invaded (including the use of fire in some cases) Undertaking physical works to protect, restore or limit the degradation of the landscape features such as soil, drainage lines Fire as a Degradation Factor Where fire has no natural role in the landscape, then the steps are much clearer. Fire needs to be controlled to reduce its pressure on the landscape. Removing fire from a landscape entirely is generally impossible accidents and very infrequently occurring combinations of factors will at some time create conditions that lead to fires Fire Used as a Tool Where fire is being used as a tool in the landscape there is first a need to clearly establish the aspects of cause: ignition, source, and motivation. Depending on the insights developed there are likely to be a range of options for landscape restoration. If fire is not impacting negatively on the landscape, there may be no need to deal with fire and restoration to meet other objectives can continue. Fire may also be used as an active tool to accelerate restoration. 2. Examples In general there are very few efforts to restore landscapes after fire anywhere in the world. Of the aspects of fire management, two prevention and restoration are notably absent and apparently ignored in most jurisdictions. Much of the work that is done on burnt areas has apparently been simplistic in origin (to stop erosion) and implementation (dropping grass seed from aircraft). Consequently in the literature and documentation there is little carefully considered fire-related restoration work described Attempting to Rehabilitate Rainforests in East Kalimantan, Indonesia Following the severe fires that burnt through Grand Park Bukit Soeharto in East Kalimantan in the 1980s and early 1990s, the timber concession companies that had responsibility for areas elsewhere in the province were required to rehabilitate the park. This has taken the form of narrow plantings of an introduced Acacia species and roadside signs identifying the company responsible for each section of the rehabilitation. While it has reestablished tree cover, the vegetation is introduced and does not resemble the forest removed or lost to the fires in terms of species mix, structure, or habitat. As part of GTZ s Sustainable Forest Management Project, which was operating at the time of the fires, the following principles were developed for the rehabilitation of fire-affected forests: Maintenance of the forest area Sustainable management of forest resources: Economically sound management targets should be defined and agreed to by the concession s stakeholders, giving consideration to the local conditions and forest functions.

5 47. Forest Landscape Restoration After Fires 335 Appropriate silvicultural treatments should be performed to reach these management targets. Ecological sustainability: Management targets should be directed toward the type of forest that is native to the area. Silviculture activities should have minimal negative effects on the remaining stand and soil and should prioritise management of the residual stand, natural regeneration, and mixed planting using local species suitable to the site. Forest protection: The forest is the foremost asset so it must be protected from pests, disease, illegal logging, fire and other disturbances. Community participation to increase community welfare through benefits from forest resources and support efforts to protect the forest 2.2. Restoration in Giant Forest Sequoia and Kings Canyon National Parks, California 409 Development in giant forest in Sequoia and Kings Canyon National Parks altered the vegetation in several ways. Trees were cleared for buildings and parking lots, leaving distinct openings in the forest canopy. The forest overstorey was thinner because trees that threatened human safety and property were removed. Trampling and soil compaction reduced or eliminated the forest understorey, including grasses, wildflowers, shrubs, and tree seedlings. The soil seed bank, which influences the regenerative potential of the forest, was likely depleted. Small patches of wetland vegetation were lost where fill was placed over meadow edges or streams. The disturbance caused by human development resembled that caused by natural, prescribed fire killing patches of mature trees, creating openings, or gaps, in the canopy. These fire-caused gaps were colonised by patches of abundant shrub and tree regeneration, particularly giant sequoia, with little regeneration beneath intact canopy. 409 Source: vegetation.htm. Shrub and tree regeneration in fire-caused gaps was mapped and the patterns of regeneration were used as a model for restoring vegetation in Giant Forest Village. The short-term goal of vegetation restoration in Giant Forest Village is to reproduce the species composition, density, and spatial pattern of regeneration that would result from a natural fire event. The long-term goal is to integrate the site into the natural fire regime typical of surrounding areas of giant forest, re-creating the range of natural variability and then allowing natural processes to thin the vegetation Restoration After Fires in Mediterranean Forest Landscapes 410 Fires are part of the natural disturbances to which Mediterranean forests are adapted. Nevertheless, during the last decades the natural fire regimes have been altered and increasingly there are large-scale, very intense, and frequent human-induced fires. From experience in Portugal, where in 2003 WWF and the local nongovernmental organisation (NGO), Associação de Defesa do Património de Mértola (ADPM), developed plans to restore forest landscapes that were devastated by fires, a number of steps were taken: Geographical information system (GIS) assessment of soil degradation and hydrologic erosion risk of the different landscape components The GIS assessment of the fire incidence in the forest cover and mycorrhizal soil component in the mosaic of habitat types within the forest landscape Analysis of the socioeconomic impact, including forecasts in productivity loss and risk of abandonment of forest uses and rural exodus Planning the different technical options to be adopted within the landscape for preventing degradation and activating the natural recovery of burned areas, including burned vegetation management techniques; 410 This example was provided by Pedro Regato, WWF Mediterranean Programme.

6 336 P. Moore it is preferable not to remove burned vegetation from the forest area, as it provides protection to soil and to the natural regeneration. Active restoration in landscape areas with risk of soil erosion and little or no natural regeneration in the first years. As much as possible, it would be preferable to promote planting by combining root-sprouting species, such as evergreen oaks, small trees strawberry tree, myrtle, mastic tree with leguminous shrubs Management of sprouting trees, mainly oak species, through cutting operations to accelerate the establishment of healthy coppice woodlands Clearance of fire-prone monospecific shrublands, for example, rocky rose shrubs and plantation of scattered trees and shrubs, as well as pasture patches to increase plant diversity, accelerate succession, and reduce the risk of fires Nonintervention in areas with low fire impact where the natural regeneration has a good after-fire response Reducing the risk of fires recurring in the forest landscape Creation of natural firebreaks within the forest landscape, especially in areas where forest management options have simplified the landscape structure (see Developing Firebreaks ). Restoring riparian forest vegetation in ravines and river networks Redesigning tree plantations where timber/ pulp commercial tree stands should be alternated with silvipastoral woodland stands dominated by oak, ash, chestnuts, juniper, stone pine, etc. Restoring the economic and social potential of the burned forest landscape Activities should be participatory in order to understand and restore the economic and social values of burned forest landscapes Restoration should be designed and planned to reduce large-scale fire risk and may imply the need for funding schemes, such as governmental subsidies or environmental services payments, to support the establishment of natural and economically beneficial firebreaks, and to diversify the existing land-use options in private and public land 2.4. Potential Adverse Impacts Adverse impacts of restoration after fires are most likely to result from the use of inappropriate (exotic) species, physical restoration efforts that change or impact soils or drainage features, or replanting that alters the preferred mix of local species. In the Bitterroot National Forest in Montana, wildfires burnt extensive areas in The amount of disturbance by both wildfires and fuel treatments before fires combined with the use of exotic seed in mixes applied for erosion control are suggested as factors in establishing invasive species in the landscape. 411 Conditions that potentially favour invasive species included increased light and nutrient levels, reduced plant competition, and exposed soil. In some sites, 2 years later, the fire weeds had increased in density and were present on plots that had previously been free of invasive species. Knapweed (there are several species) had increased in relation to the severity of fires the more severe, the higher the density of this weed.there are cases of invasive species following wildfires that reduce the chance of native plant recovery identified in New Mexico in the United States Outline of Tools The major input required for framing restoration after fires is strong insight into the fires themselves. The facts, factors, and information that need to be gathered include those listed earlier. Collectively, fire-related data, identification of the fire regime, and clarity about cause (ignition, source of fire, motivation for fire) provide a solid foundation for dealing with the fires and then restoring the landscape if it proves possible and desirable. For developing nations, fire is often perceived as part of that 411 Sutherland, Hunter et al, 2003.

7 47. Forest Landscape Restoration After Fires 337 development. Consequently analysis of livelihood requirements and sectoral use of fire in economic development is needed. Analysing fires is essential and relatively straightforward if the data and information are available. The key information is simple and the focus is on the motivation for the fires dealing with this is essential to identify the restoration strategy required and its components. Though there is no documented formal or systematic process for the analysis of fires, the process basically involves obtaining answers to a series of questions: For fires: When did the fire start? Where did the fire start? When did the fire finish? How large is the area burnt? What ignited the fire? Why was the fire started? Where are the fires likely to be? What time of year/season are fires likely to occur? For people: Who manages and influences land communities, forest agencies, concessionaires, ministry of agriculture, ministry of transmigration, provincial and district leadership, others? Who is impacted people, transport sector, tourism sector, health sector, agricultural sector, manufacturing industry? Who can assist with fires fire services, communities, forest agencies, concessionaires, ministry of agriculture, ministry of transmigration, provincial and district leadership? For those identified above: What role do they play? What is their motivation? Why should they be involved? Who is responsible and should fight the fire? Who is affected and will need/want to fight the fire? Who is responsible for fires that cause damage? Who is impacted by fires? Who should pay or undertake recovery? For the landscape: What is the ideal landscape state, given the influences of fires and people? Is there an ecological role for fire in the landscape? Should/must fire have a role in the landscape? By collating the answers to these questions as far as possible (informed guesses are sometimes the only information available), the fire picture can be framed. Once the fire situation is understood, then decisions about restoration strategies and techniques can be made. If the fires are going to be repeated, then restoration itself may not be successful or require fire management to ensure restored areas are not burnt at all, not burnt before they can be, or are ready to be burnt. 4. Future Needs There is increasing recognition of the often strong capacity communities have in fire management. Their reasons, skills, and understanding can be highly developed and should be harnessed. The community/local understanding of fire and its role as well as techniques for using fire should be the basis for improving fire management. Expanding the recognition of community-based fire management (CBFiM) and the core role people play through using fire in the landscape is essential in the context of nations where government structures and approaches are developing and resources and support may be limiting. As discussed earlier it is critical to obtain, maintain, or initiate records of unwanted fires, fire use, and fire behaviour to enable analysis to support the refinement of techniques of deliberate fire use and targeting of information and inputs to reduce unwanted impacts of fires. References Bond, W.J., and van Wilgen, B.W Fire and Plants. Chapman & Hall, London.

8 338 P. Moore Cochrane, M.A Spreading like wildfire tropical forest fires in Latin America and the Caribbean. Prevention, assessment and early warning. UNEP, Regional Office for Latin America and the Caribbean, Mexico. Gill, A.M Adaptive responses of Australian vascular plant species to fires. In: Gill, A.M., Groves, R.H., and Noble, I.R., eds. Fire and the Australian Biota. Australian Academy of Science, Canberra. Goldammer, J Global Fire Issues. In: Saile, P., Stehling, H., and von der Heyde, B., eds. WALD- INFO 26. Special Issue Forest Fire Management in Technical Co-operation. Gesellschaft für Technische Zusammenarbeit (GTZ). Eschborn, Germany. Hunter, M.E., Omi, P.N., Martinson, E.J., Chong, G.W., Kalkhan, M.A., and Stohlgren, T.J Effects of fuel treatments, post-fire rehabilitation treatments and wildfire on establishment of invasive species. Second International Wildland Fire Ecology and Fire Management congress and Fifth Symposium on Fire and Forest Meteorology, Orlando, Florida, November. Jackson, W.J., and Moore, P.F The role of indigenous use of fire in forest management and conservation. International Seminar on Cultivating Forests: Alternative Forest Management Practices and Techniques for Community Forestry. Regional Community Forestry Training Center, Bangkok, Thailand. Joint Research Center of the European Commission Global Burnt Area 2000 (GBA2000) dataset: Luke, R.H., and McArthur, A.G Bushfires in Australia. Australian Government Publishing Service, Canberra. Singh, G., Kershaw, A.P., and Clark, R Quaternary vegetation and fire history in Australia. In: Gill, A.M., Groves, R.H., and Noble, I.R., eds. Fire and the Australian Biota. Australian Academy of Science, Canberra. Sutherland, S Wildfire and weeds in the northern Rockies. Second International Wildland Fire Ecology and Fire Management congress and Fifth Symposium on Fire and Forest Meteorology. Orlando, Florida, November. Web Sites US National Parks Service Global Fire Manitoring Centre natcon/natcon_5.htm. Additional Reading Bowman, M Landscape analysis of aboriginal fire management in Central Arnhem Land, North Australia. Second International Wildland Fire Ecology and Fire Management Congress, Orlando, Florida, November. Ganz, D., Fisher, R.J., and Moore, P.F Further defining community-based fire management: critical elements and rapid appraisal tools. Third International Wildland Fire Conference, October 6 8, Sydney, Australia. Moore, P.F Fires, community action and law enforcement in S.E. Asia. Paper prepared for the Forest Law Enforcement and Governance: World Bank East Asia Ministerial Conference, September 11 13, Denpasar, Indonesia. Moore, P.F Forest fires in ASEAN: data, definitions and disaster? ASEAN Regional Center for Biodiversity Conservation, Workshop on Forest Fires: Its Impact on Biodiversity, Brunei Darussalam, March. Moore, P.F., Ganz, D., Tan, L., Enters, T., and Durst, P.B., eds Communities in flames: proceedings of an international conference on community involvement in fire management. FAO RAP Publication 2002/25. Petty, A., Banfai, D., Prior, L.D., and Lehmann, C. (2003) Introducing the Kakadu Landscape Change Project: a multidisciplinary assessment of 50 years of landscape change in the tropical Savannah Region of Northern Australia. Third International Wildland Fire Conference, October 6 8, Sydney, Australia. Reeb, D., Moore, P.F., and Ganz, D Five Case Studies of Community Based Fire Management. FAO Headquarters, Rome.