Sustainable forestry
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Image:Prettyclearcut.jpg Sustainable forestry - often relates to natural cover and forest where seed trees are left for natural regeneration. There is often powerful argument as to what is truly sustainable. This is distinct and should not be confused with sustainable forest management which has been described forest management "based on considering social, economic and environmental values when planning and implementing forest management activities and providing people with jobs, recreational opportunities and a healthy, sustainable forest, now and in the future." (Ontario Ministry of Natural Resources)
The other aspect is that usually the question of sustainability is the looking in a very narrow sense at just the timber resource - the complex ecology of the forest and its systems is usually ignored. The sensitive ecosystems are not all about the tall trees but rather the whole mosaic of forest entities.
The basic tenet of sustainable forestry is that the amount of timber yielded from a forest should be replaced at the level that the stand of trees or a forest is capable of growing without degradation of the soil, watershed features or seed source. In selection system or uneven-aged silviculture situations this means you can yield about 25 to 35% of the standing stock. It is imperative to consider the potential natural vegetation, annual growth and the basal area, combined with the amount of trees per stand to develop a management plan for area sizes from a stand to an ownership through the entire forest, as well as considering the landscape and position of the forest within it.
Many environmentalists believe that clear cutting is not a very sustainable way of forest management, while single tree management and other 'close to nature' methods are sustainable. Foresters assume that in boreal situations clear cutting imitates natural forest fire and other dynamics. Recent research has suggested that large-scale fires did not occur as often as previously suggested and that the end result of fire or other natural dynamics are not comparable with the end result of clear cutting. In boreal forest and other forests, clear cutting and intensive silviculture have been blamed for biodiversity problems.
However, considering that boreal forests have low biodiversity to begin with, these claims may be unsubstantiated. Clearcutting and other types of even-aged forest management are used as silvicultural tools to promote growth of shade-intolerant species and may be necessary in some forest types in order to promote regeneration. Levels of horizontal structural diversity at the expense of vertical structural diversity, both necessary for many wildlife species, are increased with some level of even-aged management. Selection system, or uneven-aged forest management, has low levels of horizontal structural diversity with a high level of vertical structural diversity. Thus it seems that both types of management should be considered at the landscape level.
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Old Growth Forests
Solving sustainable forestry problems requires untouched old growth reserves. If sustainable forestry is an experiment, reserves are the control of that experiment. By comparing a management regime to a close to natural setting, we can better devise schemes for optimal growth. Aside from being a good standard to compare our commercial forests to, old growth forests are a good seed source. The two-hundred year old trees in old growth forests are not representative of all the trees two hundred years ago- they are actually the most resilient trees of their time. The old trees are the trees that made it, while others did not- those trees are more disease resistant, fire resistant and fit than any other.
High grading
High grading is the practice of cutting the tallest, fastest growing and generally best trees, and leaving the dwarfed, non preferred trees to make up the gene pool of the forest. Repeated high grading is essentially genetic control prefering stunted trees. The result is a short, poor growing forest, especially when there is a lack of an outside seed source.
Fire suppression
Fire is the dominant natural disturbance in the boreal forest and is an important disturbance mechanism in many other forest types, including temperate, sub-alpine and chaparral forests. Large, stand-replacing fires, particularly in the boreal forest, determine the age distribution and spatial age mosaic of the forested landscape.
In North America, the belief that fire suppression has substantially reduced the average annual area burned is widely held by resource managers and is often thought to be self-evident. Direct empirical evidence however is essentially limited to just two studies by Stocks (1991) and Ward and Tithecott (1993), that use Ontario government fire records to make comparisons of average annual area burned between areas with and without aggressive fire suppression policies. Numerous subsequent studies have presented the same information, often in a different format (Martell 1994, Martell 1996, Weber & Stocks 1998, Li 2000, Ward & Mawdsley 2000). The proponents of these studies argue that areas without aggressive fire suppression policies have larger average fire sizes and greater average annual area burned and a longer interval between fires and that this is evidence of the effect of fire suppression.
However, the idea that fire suppression can effectively reduce the average annual area burned is the focus of a vocal debate in the scientific literature. In particular, several recent papers have argued against this idea (Miyanishi & Johnson 2001, Miyanishi et al. 2002, Bridge et al 2005). These papers claim that statistically rigorous techniques for estimating the average annual area burned, called the fire cycle, do not show changes in the fire cycle associated with fire suppression and that the evidence used to support the effect of fire suppression is biased and has been presented in a way that is flawed. Note that none of these papers criticize fire management agencies for being anything less than completely committed to their mandate. Nor do they suggest that fire personnel are not well trained, efficiently deployed or well managed. Instead, these papers simply suggest that despite the resources employed, fire management agencies are simply unable to effectively reduce the average annual are burned.
The impact that effective fire suppression may have on the average annual area burned is important for many reasons, but in particular, its impact is key to the current paradigm of sustainable forest management in many jurisdictions. One of the core aspects of SFM in many jurisdictions is the use of wood supply models to determine sustainable harvest levels. This determination of sustainable harvest levels often assumes that fire suppression has been effective at reducing the average annual area burned. Thus, if current assumptions about the effect of fire suppression are wrong, the impact on SFM could be substantial.
Evidence that fire suppression has been effective
For the most part, studies that support the effects of fire suppression compare either the number of fires or the average fire size between areas with and without aggressive fire suppression policies. Typically, these studies use the same or similar data from provincial fire records for Ontario covering a span of about 20 years.
Proponents of these studies have argued that, firstly, fires are, on average, much larger in areas without aggressive fire suppression policies than in areas with aggressive fire suppression policies because these fires are allowed to spread freely. Secondly, the proponents have argued that far more lightning caused fires are detected in areas with aggressive fire suppression and yet, the average annual area burned is much higher in areas without aggressive fire suppression. It is implied that fire suppression must, therefore, be reducing the area burned by lightning fires.
Evidence that fire suppression has not been effective
On the other side of the debate, the evidence that fire suppression has not been effective at reducing the average annual area burned has come primarily in two forms. Firstly, in the form of time-since-fire studies, which, it has been argued, do not show detectable changes in the fire cycle that can be associated with fire suppression. Secondly, in the form of criticism of the way that provincial fire records have been used to support the effect of fire suppression.
Numerous time-since fire studies have been done in the temperate, boreal and sub-alpine forests across Canada and the U.S. (reviewed in Johnson 1992, see also Bergeron & Archambault 1993, Johnson & Wowchuck 1993, Johnson et al. 1995, Weir et al. 2000). The techniques used in these studies are felt to be well founded in statistical theory (Johnson & Van Wagner 1985, Johnson & Gutsell 1994, Reed 1994, Reed et al 1998) and recent improvements offer a way to statistically compare different periods of time to see if they possess significantly different fire cycles (Reed 1994, Reed et al 1998). While these studies often show a change in the fire cycle at the beginning of the 20th century, this change is usually associated with large-scale climatic factors, such as the end of the little ice age (Johnson 1992, Bergeron & Archambault 1993, Weir et al. 2000), and not fire suppression. In particular, around Ontario there have been at least six time-since-fire studies that show there has been no change in the fire cycle since 1920 (Heinselmann 1973, Woods & Day 1977, Suffling et al. 1982, Bergeron 1991, Gauthier et al. 2000, and Bridge et al. 2005). In Ontario, active fire suppression activities began sometime in the late 1910's, but these suppression activities are generally thought to be minimal compared with post 1950 when fire suppression began in earnest and technological advances made fire fighting much more effective (OMNR 2002, Thompson 2000).
Comparisons of the average annual area burned between areas with and without aggressive fire suppression policies, it is argued, are biased by the fact that small fires are virtually unreported in areas without aggressive fire suppression policies, where detection often relies on reports from settlements or commercial aircraft. Critics have argued that the number of lightning caused fires in areas with and without aggressive fire suppression policies are in fact quite similar and that the smaller average fire size, and the lower proportion of fires in larger size classes in areas with aggressive fire suppression is clearly a consequence of this bias (Miyanishi & Johnson 2001, Miyanishi et al. 2001).
Critics have also argued that despite suppression attempts the actual number of large fires in both areas is quite similar (Miyanishi & Johnson 2001, Miyanishi et al 2001). It has been argued that if fire suppression cannot impact the large fires, then it cannot impact the average annual area burned since almost all of the area is burned by only a few large fires.
Finally, studies that compare areas are also often based on averages of annual area burned made over periods of 12 to 17 years (Martell 1994, 1996, Ward & Tithecott 1993, Li 2000). Some have argued that this is too short a time period because the extreme year to year variation in area burned makes such averages highly variable and difficult to interpret (Johnson et al. 1996, Weir et al. 2000).
Reasons why fire suppression may not have effected the fire cycle
Several people (Weir et al. 1995, Johnson et al. 1995, 1998) have explored reasons why fire suppression may not have effected the fire cycle. In general, they feel that in closed-canopied forests, like the boreal, as little as 3% of the lightning caused fires account for up to 95% of the area burned (Stocks & Street 1993, Johnson & Wowchuck 1993). Most fires remain small, but a few occur under conditions that allow them to increase rapidly in size. It is this small proportion of large lightning caused fires which has the most influence on the area burned and the fire cycle.
In years with a large area burned, fires in these closed-canopied forests characteristically have high intensities, high rates of spread and high duff consumption. In these years, extreme fire behaviour is preceded by a persistent anomalous high pressure system which produces prolonged periods of above normal temperatures and below normal precipitation (Newark 1975, Harrington & Flannigan 1987), and leads to the severe drying of both medium and heavy fuels. Under these extreme conditions, fire behaviour exhibits little difference between aspect, elevation and vegetation type (Anderson 1968, Alexander et al. 1983, Nimchuck 1983, Janz & Nimchuck 1983, Street 1985, Flannigan & Harrington 1988, Fryer & Johnson 1988). In years with only a small area burned, differences in aspect, slope, elevation and vegetation composition can have a significant effect on the fire behaviour (Alexander & McAlpine 1987, Johnson et al 1998), however, the area burned in these years is insignificant.
The extreme fire behaviour associated with persistent high pressure systems results in large areas burned. It has been argued that during these years, it is unlikely that fire suppression can significantly influence the total area burned because under these conditions fire management agencies are quickly overwhelmed (Weir et al. 1995).
Areas where it is agreed fire suppresion has been effective
One area where it is largely accepted that fire suppression has altered the “natural” fire regime is the Pinus ponderosa ecosystems in the interior West of the United States, where a historical regime of frequent surface fires had maintained open-canopy conditions. With the arrival of European settlers, the frequency of surface fires decreased, changing both the accumulation and arrangement of fine fuel. Growth of an intermediate-height ladder of vegetation and the increased bulk density of canopy fuel allowed surface fires to burn into the crown, thus creating a crown-fire regime (Fuli et al. 1997, Shinnerman & Baker 1997).
Harvest
Harvest of trees can deplete nutrients, as many nutrients are held in the trees. This is especially unfortunate when considering that humans do not use the nutrients in the trees in our lumber and paper products. Harvest often doesn't allow for different successional stages. Forests have different stages of height, age and species diversity, and different animals depend on each. Some harvest techniques eliminate one or more stage of forest development, reducing the value of the wildlife in the forest, and reducing the health of the trees overall.
Fragmentation
Urban sprawl and other construction can fragment forests. This creates edge habitat, habitat not protected by other trees and exposed to an urban environment. If the same area of forest is spread over different fragments, than there will be more edge than if all of that area were in one lump. If that same area is in a narrow line, then all of the forest becomes the degraded edge with little or no middle. Edge trees are not protected from storm wind, and are more easily consumed by deer. The wildlife living along the edge will suffer predation by racoons or may simply leave because the species will not live that close to humans. There is also the problem of dispersal between fragments. If a part of a contiguous stand of trees is damaged, it can be repopulated by the existing trees around it. However if that stand happened to be a part of a fragment with no dispersal from the rest of the fragmented area, it would take human intervention to maintain the stands. Wildlife species with poor dispersal would suffer in this situation also, even including some birds that will very rarely fly over highways.
Criteria and Indicators of Sustainable Forest Management
Forests provide a multitude of benefits but pressure on the resource is growing as use of the forest encompasses more than just the traditional industry. Citizens are demanding more information about the resource, more options for using the resource, more involvement in decision-making, and more equitable sharing of benefits. The marketplace seeks assurances that products come from forests that are managed sustainably. To meet these challenges, policy- and decision-makers need tools to define and measure progress toward SFM.
Criteria and Indicators provide such a science-based tool. Criteria represent forest values that society wants to enhance or sustain while the indicators identify scientific factors to assess the state of the forests and measure progress over time. Collectively, they provide a framework for reporting on the state of forests, forest management, and achievements in SFM.
Criteria and Indicators are developed in collaboration with stakeholders and are intended to:
- Provide a common understanding of SFM
- Provide a common framework for describing, assessing and evaluating progress toward sustainability at the national level;
- Provide a reference point for the development of policies on the conservation, management and sustainable development of forests;
- Provide a basis for international cooperation aimed at supporting SFM;
- Contribute to the clarification of issues related to environment and trade; and
- Develop concepts and terms that facilitate the on-going domestic and international dialogue on SFM.
Criteria and Indicators is the only science-based tool broadly supported by the international forest community that integrates across environmental, social and economic strata to demonstrate progress toward an internationally agreed definition of sustainable forest management (SFM). The concept of C&I was introduced in the early 1990's. By 2005, more than 150 countries had developed national C&I frameworks through their involvement in one or more of nine major international C&I processes.
Two of the most successful C&I processes are the Ministerial Conference for the Protection of Forests in Europe (MCPFE), sometimes called the Pan-european process or the Helsinki process, and the Working Group on Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests, usually refered to as the Montreal Process. Countries involved in these processes have produced national reports describing their progress toward SFM.
At the sub-national level, some states and provinces within countries also have their own C&I frameworks and, at the local level, the Center for International Forest Research and the International Model Forest Network have been using the development and implementation of C&I as a way to bring local stakeholders together to identify community values, increase participation in decision-making and help citizens realize new opportunities to use the forest resource for the benefit of all.
Certification
Growing environmental awareness and consumer demand for more socially responsible businesses helped third-party forest certification emerge in the 1990s as a credible tool for communicating the environmental and social performance of forest operations.
There are many potential users of certification, including: forest managers, investors, environmental advocates, business consumers of wood and paper and individuals.
With forest certification, an independent organization develops standards of good forest management, and independent auditors issue certificates to forest operations that comply with those standards. This certification verifies that forests are well-managed—as defined by a particular standard—and ensures that certain wood and paper products come from responsibly managed forests.
This rise of certification led to the emergence of several different systems throughout the world. As a result, there is no single accepted forest management standard worldwide, and each system takes a somewhat different approach in defining standards for sustainable forest management.
Third-party forest certification is an important tool for those seeking to ensure that the paper and wood products they purchase and use come from forests that are well-managed and legally harvested. Incorporating third-party certification into forest product procurement practices can be a centerpiece for comprehensive wood and paper policies that include factors such as the protection of sensitive forest values, thoughtful material selection and efficient use of products (Source: Forest Certification Resource Center)
Some common certification standards are:
The area of forest certified worldwide is growing rapidly. As of December 2005, there were over 2,420,000 square kilometres of forest certified under the CSA, FSC or SFI standards, with over 1,190,000 square kilometres certified in Canada alone (Source: Canadian Sustainable Forestry Certification Coalition).
While certification is intended as a tool to enhance forest management practices throughout the world, to date most certified forestry operations are located in Europe and North America. A significant barrier for many forest managers in developing countries is that they lack the capacity to undergo a certification audit and maintain operations to a certification standard.
Solutions
Using untouched reserves as a model, we can try to recreate those better forest conditions. Selection cutting is a practice which mimics a natural disturbance like a tree falling down. If we can mimic natural conditions, trees have been evolving to grow well under those conditions far longer than under modern forestry conditions, and our mimicry will yield better trees. Selection cutting is based on gap sizes and woody debris found in our natural reserves. Sustainable forestry also involves re-introducing fire to forests. This has the added benefit of bringing back a variety of wildlife species. And there are also harvest practices that can allow all successional stages of a forest to exist.
Dispersal corridors are lines of habitat that go between fragments so that beneficial wildlife can travel at a regualar rate between forests. This helps lichens and poor dispersing plants and animals to survive inbetween forest fragments. However, this does not reduce edge effects or help protect trees from the wind. It can help the trees cross pollinate and expand their gene pool, however.
References
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