Any investment in sustainable forest management in temperate and boreal forests requires a few solid foundations, including the following:
_ sufficient funding;
_ continuous education and training of the workforce;
_ access to the forest (even after harvest), requiring a network of permanent roads and other infrastructure;
_ accurate and detailed field instructions for all of the various silviculture measures that will be employed, including nature conservation measures (this is particularly the case in large-scale forest operations);
_ maps and compartment records that are both accurate and readily available; and
_ appropriate systems for planning and control of all forest activities.
The list could be made much longer.
Sustainable forest management in temperate and boreal forests is also often based on the practice of clearfelling, which usually involves the following sequence of events:
_ harvesting (i.e. clearfelling);
_ site preparation;
_ planting, direct seeding or natural regeneration;
_ tending the young stand (e.g. weeding, respacing, pruning, etc.);
_ fertiliser application (in some cases);
_ commercial thinning or thinnings; and
_ fertiliser application (in some cases).
Generally speaking enough theoretical knowledge and practical experience currently exists to successfully implement this type of forest management system (where applicable) in temperate and boreal forests. Depending on the intensity of management and the type of forest ecosystem, some of the above elements above can be excluded or exchanged. In many cases, for example, a new stand can be established by utilising already existing seedlings or the lower tree vegetation left after harvest.
Seed trees are often also frequently left to regenerate the stand, or the original stand can be gradually opened up by repeated thinnings to allow natural regeneration to establish under the shelter of the big trees. Taking this to its limit, the Plenterwald (selection forestry) system utilises perpetual selective harvesting only and results in forest stands with a constantly similar mixture of trees of different ages and different species. At present, the Plenterwald system is used only in rather limited areas in parts of Central Europe. Selective harvesting systems that are similar to the Plenterwald system also seem biologically ideal for some forest ecosystems in wet temperate zones (e.g. on the west coast of North America). However, there are a few problems with implementing such systems under the conditions typically found on the West Coast of North America:
_ it is costly to remove giant trees in difficult terrain without seriously damaging the rest of the forest stand; and
_ there is an enormous hazard to workers using such a system in this particular forest environment, where the trees that will be cut are surrounded by many large unstable trees (e.g. snags) that might also fall over.
In light of the present critical attitude and actions against clearfelling in this region though, it is necessary to use aesthetically less controversial and more environmentally friendly harvesting methods. This has forced forestry companies to try new harvesting practices, which can be described as a compromise between selective cutting and clearfelling. The new felling methods that are currently being tried are by no means certain to persist in the future though and should be regarded as an experiment in new logging techniques.
In terms of profitability and simplifying forest operations, clearfelling and the subsequent cultivation of even-aged planted forest stands in the next generation, will always generally be the best forest management option. Consequently, until recently, this system has tended to the most common forest management system found across the temperate and boreal forest zone. When this system is used in gentle terrain, the results are often startling. But, on steep slopes, this practice has led to serious problems (such as landslides and erosion) and has been criticised.
In addition to the never-ending efforts to keep costs under control and improve forest yield, the present trend in the development of silvicultural practices in the temperate and boreal forest zone is to develop realistic, effective and operationally feasible measures to conserve nature and meet demands for other non wood forest products and services. This is probably the biggest challenge for today's foresters, because scientific research continues to present new information on environmental issues. Clearfelled areas should nowadays be designed to fit into the landscape and special areas and an appropriate number of old trees should be left during clearfelling operations. Protection of watercourses is also given a high priority in most areas. In order to plan such operations effectively, it may be necessary to survey the clearfelling area, the whole forest estate or even adjoining areas as well in order to implement sustainable forest management. This requires better education and retraining of forest machinery operators and other forest workers, so that they understand what they should be trying to achieve and can act accordingly as part of their jobs.
Current evidence suggests that the major large-scale forest operators in most western countries in the temperate and boreal forest zone, are acting seriously to meet these new and constantly changing demands. There is a problem though, with getting the message of sustainable forest management across to the vast number of small private forest owners. In a number of countries, government forest administrations, forest owners organisations and even wood buyers, are working hard on the task of educating and encouraging small forest owners to pay attention to the importance of nature conservation and the other demands now being placed upon the sector.
Harvesting in large-scale forestry operations in western countries is currently nearly always highly mechanised, using a number of different machines (including: harvesters; processors; forwarders; and skidders). There are also other ground-based harvesting systems and cable systems that are used to extract timber from the forest. These are mostly used in steep terrain, particularly for the handling of very heavy logs or whole tree stems. In terms of ground-based machinery, the general trend is towards lighter, more mobile and computerised machines that can automatically optimise the value of harvested trees when cutting them into product assortments and cause little damage to forest soils and remaining trees.
Power-saws and small tractors (occasionally even horses and oxen) are still used extensively in Eastern and Central Europe (and in some other areas) and in small-scale forestry operations. But, it is generally accepted that, in many countries, more has to be done to develop appropriate machinery for the millions of small private woodland owners who want to manage their own forests, but cannot afford the significant investment in sophisticated machinery such as that used in large-scale operations.
Various types of cultivators or ploughs are used for preparing forest sites for planting or direct seeding or, where necessary, to improve the seedbed for natural regeneration. The trend is to minimise the soil disturbance as much as possible if this is possible, within the overall aim of the creating a favourable environment for the next crop of trees.
Nowadays, the seeds used to produce seedlings for planting are often grown in seed orchards; otherwise they are collected in the forest. Large forest owners often have their own tree nurseries and seed orchards. Containerised seedlings are mostly used in large-scale forest operations in the boreal forest zone. In temperate forests, the use of bare-root seedlings is more common.
The tending of young forest stands includes a number of possible treatments depending on the site conditions, type of forest and tree species. Respacing or cleaning operations, which determine which trees will eventually form the future stand, are very important. A current trend is to avoid, as much as possible, the creation of monocultures, but rather to create a mixture of species (e.g. by encouraging some hardwoods in a softwood stand) if this is possible. Circular saws, ordinary power-saws, or hand tools are used for these operations.
Pruning individual tree-stems is still a common practice in European beech and oak forests and is sometimes employed in commercial conifer plantations all over the world. With increasing labour-costs and the difficulty of further mechanising operation such as pruning and other forest tending measures, a real challenge for forest managers is to find cheaper ways of carrying out these important measures. This will become an even greater challenge in the future, considering the present trend towards the use of more broadleaves in managed forests.
Pesticides and herbicides are used throughout the temperate and boreal forest zone on a limited scale. Pesticides are regarded as unavoidable to prevent or defend the forest from outbreaks of insect pests. However, there is a trend towards the greater utilisation of biological means of control.
Fertiliser application is used to improve the mineral content of the soil or to more directly boost tree growth. Forests planted on organic soils (i.e. peats) often need repeated fertiliser applications in order to become properly established. This is done on a large scale in several countries (e.g. Finland, Ireland and the United Kingdom). Nitrogen fertilisers are applied to middle-aged and mature forests growing on mineral soils, to improve forest growth and result in an increase in the sustainable harvest level. This technique is utilised by large-scale forest owners in, for example, the Nordic countries and the Southern United States of America. Forest owners in most countries now avoid using fertilisers near watercourses or other protected areas.
All over the world, increasingly larger areas of managed forest are reaching the commercial thinning stage in the temperate and boreal forest zone. In eastern and central Europe, vast areas of forests were almost totally destroyed during World War II, which was followed by huge forest replanting programs. Most of these forests have now reached the thinning stage.
However, there is not enough industry capacity to consume the forecast increase in the potential production of small roundwood from thinnings, particularly in Eastern Europe. If these forests are not thinned, this may lead to sanitary problems in the forest, as they become overstocked, increasingly difficult to mange and susceptible to pests and fire. There is, therefore, a need to encourage the forest products industry to consume more small sized wood from these areas.