This section describes the main characteristics of forest management, harvesting and silviculture in temperate and boreal forests, before describing some of the challenges they present for the implementation of sustainable forest management in temperate and boreal forests.
The management of temperate and boreal forests is both large-scale and small-scale. In the Northern Hemisphere there are more than 20 million small private forest owners, about equally divided between North America and Eurasia. In the temperate forest zones, large-scale private (corporate) forest operations are to be found mainly in the United States of America and in the Southern Hemisphere. The boreal forest is mostly owned by the state, except in the Nordic countries where small private and corporate forest owners dominate.
In European countries with many private forest owners, very strict forest legislation has often been established that requires management of their forests according to various sustainable yield principles. Legislation also usually demands environmental protection and nature conservation to various degrees. Most countries have government agencies with the task of advising private forest owners and ensuring that management is carried out in line with legislation. In North America private forest owners have much more freedom over how to manage their forests.
Modern management of larger forest holdings utilises forest inventories, maps, aerial photos, stand databases etc., as important tools for forest management and planning. Many managers have computerised systems that utilise very accurate satellite remote sensing systems to keep track of, for example, the geographical location of all individual forest stands, roads and ownership boundaries. In addition, detailed information about important forest characteristics such as: tree species composition; age; increment; quality and standing volume of wood, are available down to the forest stand level in may cases. At the national level, most forest-rich western countries conduct regular national forest inventories. These give information (with various degrees of accuracy) about important forest features, making it possible to follow and calculate, for example, changes in the national forest estate subdivided into regions and types of forest owners.
In Sweden, a very accurate National Forest Inventory has been carried out since the early 1920´s. It is based on a yearly field survey of sample plots spread out over a grid-system. This is probably the most accurate and detailed forest assessment in existence. It is based on statistical sampling and, thus, gives information with a known standard error. Larger forest-owning corporations also frequently use the same or similar methods. Less reliable but still useful information can be obtained from aerial photographs and satellite images. When supplemented with field surveys, the accuracy of such information can also be estimated. This type of assessment has been widely used in Canada and the former Soviet Union, where it is used to monitor vast inaccessible forest areas.
Apart from statistically based forest assessments such as these, the traditional way to assess forest resources in well organised forestry enterprises was to estimate data by utilising information from existing stand records covering the whole forest estate. This method may work well if the information is accurate and fresh but, due to various types of bias and other problems, this method is often not very useful for the purposes of producing data covering larger forest areas.
Most European temperate forests have been managed according to "classical" sustainable yield principles for a very long time. This is true even for countries in Eastern Europe that were formerly under the influence of the Soviet Union. In the west, especially in France, vast areas of deciduous forests have been cultivated on short rotations for the production of fuelwood under so-called "low forest" regimes. Many of these forests are now being converted back to high forest management.
In Britain and Ireland, considerable areas of forest plantations have been established utilising exotic trees, mainly: Sitka spruce; Norway spruce; Lodgepole pine; and Douglas fir. In Spain and Portugal, the same is true with Radiata pine and Eucalypti. All of these forest plantations are now yielding increasing quantities of industrial roundwood.
In Chile and New Zealand, considerable areas of natural temperate forests have been converted into forest plantations, which nowadays yield most of the industrial roundwood produced in these countries. Radiata pine and various Eucalypti are the most common species found in these countries. The further expansion of this very successful plantation forestry model, at the expense of the natural forest, has been limited by legislation in New Zealand and is, at present, under debate in Chile.
Because temperate forests vary a lot with respect to ownership, management history and management objectives, forest harvesting practices vary a lot too. In some places in Central Europe the hand axe and horse is still the most common means of harvesting and extraction. A few hundred kilometres further west, modern sophisticated processors and forwarders are doing the same kind of job. Differences such as these can also be found in North America.
In North America, industrial forest harvesting is mostly highly mechanised. Most operations are similar to those found in the boreal forests and are driven by concerns about profitability, cost efficiency, and operational control. Clearfelling is very common in harvesting operations in mature softwood stands. In sensitive areas, various types of selective harvesting systems are practised, both in coniferous and deciduous forests (except, until recently, in harvesting operations along the Pacific Coast). Harvesting is usually carried out by companies, contractors or small-scale loggers, regardless of the type of forest or forest ownership.
In Central Europe, clearfelling is usually restricted to a few hectares for various reasons (e.g. aesthetic, biological, risks of erosion, etc.). Instead, forests are (or should be) intensively thinned. Many Central European foresters prefer to use manual harvesting methods and/or light harvesting equipment that prevent soil damage. This is a difficult proposition when it comes to the handling of tall, heavy trees, which often grow in these forests. In comparison with forestry in the boreal zone, such considerations make these operations relatively more expensive.
The silvicultural practices used in temperate forest management are numerous and cannot be dealt with here in detail. Traditional labour intensive forest management techniques are still commonly employed in much of Central Europe. These include such practices as numerous tending operations in young oak and beech stands and the simultaneous trimming of individual stems. Therefore, generally speaking, forest management costs tend to be very high, but the results are excellent. In other areas, reforestation after clearfelling is carried out in the same way as in boreal forests, utilising both natural and artificial regeneration. This is true for large parts of North America. However, one difference in North America is the intensive forest establishment methods used in the Yellow pine areas of the Southern United States of America, which include complete soil cultivation, bedding and planting.
Later stand management operations generally include frequent or occasional thinnings. Fertiliser is also often applied nowadays, especially in company owned pine plantations in the Southern States of America and in cultivated second-generation forests on the American West Coast.
In Central Europe one traditional school of forest management utilises a particular type of selective cutting - the "Plenterwald" (selection forestry) system. The concept of the Plenterwald system is to create, conserve and utilise mixed (often hardwood dominated) forest stands of uneven age, by harvesting single trees as they reach maturity. In addition, some trees of smaller sizes are harvested during these operations, to keep the composition and structure of the forests in a particular state in perpetuity. Technically, the system works well in forests containing shade tolerant tree species. It becomes more difficult to use, or even impossible, for light demanding species such as pine or larch.
The Plenterwald system has attracted the attention of today's environmentalists who perceive this as a very eco-friendly forest management system and, therefore, biologically superior to even-aged forest management. This is probably true for some hardwood-dominated ecosystems, which also may include shade tolerant conifers, but the opposite is true in circumstances where light demanding tree species are growing. It is also regarded as an aesthetically more acceptable forest management system.
In Central Europe, there is a trend towards the greater use of the Plenterwald system, particularly in publicly owned forests. On the American West Coast, selection forestry systems have also been recommended by some forest ecologists as biologically suitable for the coastal "rainforest".
In boreal forests, roughly 75 percent of total annual removals of industrial roundwood come from large-scale final felling in natural forests situated on public land in the Russian Federation (about 50 percent) and Canada (about 25 percent). Here "large-scale" means removals during clearfelling operations over areas that often cover 25 ha to 100 ha or more and yield tens of thousands of cubic meters of wood at a time. Most of the rest of the industrial roundwood harvest in the boreal forest zone takes place in the Nordic countries. Here, the large-scale forest industry operates in a similar way, although the forests being harvested in most cases are second-generation or third-generation forests rather than primary forests.
Generally, forest harvesting in boreal forests is characterised by large-scale harvesting operations. Consequently, harvesting operations in the boreal forest tend to utilise high levels of mechanisation and, at least in western countries, these forests are largely harvested with the aim of maximising cost efficiency, operational control and profitability. Even in forests belonging to small private forest owners, which are mainly to be found in the Nordic countries and Eastern Canada, harvesting methods do not differ much, generally speaking, from those of the larger forestry operations. One reason for this is that small private forest owners often sell their wood standing to the industry, which then use their own equipment or contractors to harvest the timber. Another reason that mechanisation is so common, is that current harvesting machines are very flexible and can perform very well (i.e. they are very cost effective) even when they are harvesting small areas.
The reforestation methods used after clearfelling in boreal forests are more or less the same throughout the zone. Natural regeneration, either spontaneous or under seed-trees or shelter-wood, is widely used. Experience shows, however, that as management becomes more intensive (e.g. with the use of selected tree species with, maybe, genetically improved properties) planting or, in some cases, direct seeding of sites, becomes a more common way of reforesting clearfelled sites. It is also more common nowadays to precede replanting (and often also natural regeneration) with some type of soil treatment (e.g. scarification or controlled burning), which makes it easier for seedlings to establish themselves. In some areas however, shade tolerant fir trees regenerate in sufficient numbers without any special measures at all.
After some time, immature boreal forest stands are ready for pre-commercial thinning (or respacing), which is used to improve the structure and condition of the future forest stand. This labour-intensive but important investment for the future is difficult to mechanise and it is, therefore, tempting to postpone this operation until it is too late.
The next stage in the development of the forest crop is commercial thinning, which starts when the trees have become large enough to be utilised and stocking has reached a level where some of the growing stock can be removed. Thinning has been a common practice for many years in the Nordic countries, but is less common elsewhere in the boreal forest zone. Outside of the Nordic countries, the second-generation boreal forests have mostly either not yet reached the thinning stage or there is no market for the small diameter wood that such thinning would produce.
The application of fertiliser in boreal forest stands is used in the Nordic countries to boost tree growth in closed forest stands or to provide the basic essential nutrients on mineral-poor peat-land. However, fertiliser application in forest stands is less common elsewhere in the boreal forest zone.
Aerial spraying against insect pests is regarded as unavoidable in many areas of the boreal forest, in spite of the clear environmental impacts of such operations. An example is the large scale spraying against the spruce budworm in Eastern Canada and adjacent parts of the United States of America, which regularly takes place. In many areas, newly planted seedlings must also be treated with insecticides to prevent planting failure. The use of herbicides in the boreal forest is prohibited in some western countries but is permitted in others (with various restrictions on the use of such chemicals).
It notable that in the boreal forest (and, to a lesser extent, the temperate forest) forest management and harvesting is important for the national economy and the livelihoods of many individuals. Many countries in the temperate and boreal forest zones are also where the greatest demand for forest products exists. Consequently, apart from a few remote forest areas in the boreal forest zone, most of these forests are intensively managed and used for the production of industrial roundwood. In a world with an increasing population and, consequently, increasing consumption of wood products, the important question is therefore: "how can these forests be managed even more effectively than today, in order to produce industrial roundwood for the benefit of mankind?" The challenge that forestry is currently facing is how to combine this task with demands to preserve a reasonable portion of unaffected forest ecosystems and demands to conserve biodiversity more widely. Policy-makers in different countries with temperate and boreal forest areas have, in the past, tended to take different positions on this issue.
Intensive forest management, which may include operations such as: site preparation; tree planting (including, sometimes, the use of genetically improved trees and/or exotic tree species); tending; thinning; and fertiliser application, is often criticised as being inconsistent with the goal of achieving an acceptable level of forest biodiversity. However, forest managers argue (and many scientists agree with this argument) that a reasonable level of biodiversity can be preserved even if a major portion of the forest is managed intensively as long as these forests are managed in a way that is reasonably environmentally friendly. For example, leaving a few snag trees, hollow trees and other dispersed trees that are ecologically important, can provide refuges for species to re-colonise forest areas that have been newly established after clearfelling. Furthermore, even under intensive forest management, some forest areas can be left untouched as reserves for biodiversity conservation. These areas should be selected so that they form a continuous web in the landscape and include ecotypes that are particularly valuable for conserving biodiversity. This relatively new management concept is sometimes called "landscape ecosystem management" or "landscape planning".
The landscape planning approach to forest management has been widely practised in Nordic countries, North America and elsewhere, for more than a decade now. It leads to higher silvicultural costs, but also to a high and predictable yield of industrial roundwood. Indeed the overall development of the whole managed forest area is reasonably well predictable with this approach. This is important when choosing an approach to sustainable forest management that is both realistic and viable.
Another approach to sustainable forest management in temperate and boreal forests is to practise low intensity forestry. This has lower reforestation and silvicultural costs than the landscape planning approach. It is often based on natural regeneration or some type of selective harvesting system and results in little interference with the natural development of the forest stand. Biologically, this approach may work well in stands that are easily regenerated or stands that contain trees that regenerate well. If well planned, this approach also has good prospects to satisfy nature conservation objectives and result in minimum damage to valuable ecosystems.
However, the long-term consequences of low intensity forest management, particularly concerning future yields of industrial roundwood and wood quality, are uncertain and difficult to predict. The validity of this approach as a viable approach to sustainable forest management is, therefore, somewhat questionable. For example, experience from the widespread practice of selection forestry in the Nordic countries in the past, have shown that there is a risk that this approach may lead to slowly deteriorating forest conditions and a gradual loss of biodiversity. These effects have also been shown to worsen over time and may be difficult, or even impossible, to rectify once they have occurred.
With few exceptions, large-scale forest operations in western countries currently seem to favour the landscape planning approach to sustainable forest management, when they are managing their own forestlands. However, this is sometimes in contrast to the situation faced by forest leaseholders operating on public land. In Canada for instance, forest operations in the boreal forest must follow environmental prescriptions formulated by the landowners (i.e. the provincial governments). These may, in some cases, require forest managers to carry out silvicultural and harvesting operations that are similar to the low intensity management approach. In countries that still have large areas of untouched commercial forests, such as in Canada, the harvesting area could in theory be extended to compensate for the lower yields per hectare. This is of little comfort though to companies that have existing wood processing mills that have been located and depend on industrial roundwood production from currently leased forest areas.
If major forest owners have to start to cut back production due to stricter nature conservation policies (e.g. as has happened in the United States of America when the US Forest Service started to reduce harvesting on the national forest estate), wood shortages may lead to negative effects elsewhere. This may lead to greater pressure on other forest areas to produce industrial roundwood and the delicate balance between sustainable wood production and the conservation of nature may be upset elsewhere.
In Central Europe, the situation is somewhat different. The sudden appearance of sick or even dying forests during the 1970´s was soon linked to the enormous increase in fossil fuel burning over the last few decades in many of these countries and their neighbours. However, what also became obvious was that part of the problem was that planted forests that were poorly adapted to their locations suffered the most damage. The substantial forest dieback started a kind of "back to nature" movement within forestry circles in Central Europe, which demanded changes to forestry practices and, in extreme cases, changes in the whole composition of the forest estate. Consequently, in Central European publicly owned and managed forests, there is currently a major transition underway from classical even age-class forest management for commercial softwood production towards uneven-aged mixed hardwood forest management. The latter type of forestry is regarded as being more resistant to potential stress ands damage from air-pollution and, at the same time, more useful for meeting non-commercial objectives, which are considered important in these densely populated areas.
Many private forest owners' organisations take a very critical attitude towards this change. They consider that it is unrealistic to expect that the transition can be implemented on a large-scale and are concerned about the economic effects such a change would have on their members if it were to be forced on them. They also claim that forest managers currently maintain a reasonable level of biodiversity with their present forestry practices. Even the forest products industry is concerned and fears that they will face a future drastic decline in wood supply and increased roundwood costs in the future if such practices become more common.
