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Otto K. Sedlak1

1 Director, Austrian Forest Service, Amt der o.ö. Landesregierung, Anzengruberstraße 21, A-4020 Linz, Austria.
Telephone: (43 7720) 4660; Facsimile: (43 7720) 4698


There is a distinct difference concerning regulations of forest development between countries of Central Europe, e.g. Austria, Germany, Switzerland, with "old", well-established forestry systems and "young" countries, e.g. Australia, Canada, New Zealand, with a rapidly developing forestry sector oriented towards sustainable production and environmental restrictions. While the former amended gradually their traditional forest legislation according to modern requirements in a more general way, the latter try to regulate forest road construction in the context of forest harvesting in detail by means of forest practices codes close to textbooks which are either recommended or even enacted.

A joint problem of the forestry sector on the political and practical level worldwide is environmental concern about forest development and utilization. Instead of a permanent confrontation, pragmatic and integral solutions must be found that are well adapted to the socio-economic and environmental conditions of a country.

The author deals with Austrian and international experiences in policies and regulations of planning and building forest roads in the context of multi-purpose management and environmentally friendly techniques. Additionally the paper contains a chapter on practical recommendations oriented towards a roading performance in compliance with the legal requirements. The annex contains some facts and figures of Austria, which decidedly influence the forestry system.

The Austrian forest legislation - A brief review

Forestry regulations in Central Europe date back to the Middle Ages as construction timber and fuelwood were commodities of prime economic importance at that time. Especially in the Alpine mountains of Austria the production of salt and iron depended on the steady delivery of huge quantities of fuelwood and charcoal so that forest assessments aiming at a regular forestry system with sustainable yield commenced in that region in the early sixteenth century.

Though numerous forestry regulations existed in the Austrian provinces in the mid-nineteenth century, many mountain forests were in a wretched condition because of overutilization and extensive livestock grazing. A critical situation in retrospect, which is still comparable to depleted mountainous areas in many developing countries today.

Flood and avalanche catastrophes led to public awareness of the serious problem and to a turning point of forest policy. In 1852 a federal Forest Act came into force paving the way for a modern forestry system in the entire former Austrian Empire. This development was greatly enhanced by the industrial use of fossil energy instead of fuelwood and charcoal and the extension of the railway and road system. The basic key rules of this Forest Act are still valid today:

· protection of forest land against clearing;

· compulsory reforestation or natural regeneration after harvesting;

· preservation of forest stands against malpractices;

· special management of protection forests on steep slopes, unstable ground, and along riverbanks.

These principles of forest preservation and improvement were supplemented by many practice rules, e.g. for felling and timber transportation, the latter depending mainly on ground skidding, floating and rafting at that time.

Additional provincial regulations supplemented this federal act mainly by limiting clear-cut areas.

During the implementation of the forest legislation a Forest Service and additionally an Organization for Torrent and Avalanche Control were established and upgraded during the following decades.

The Forest Act was valid for more than 120 years and outlived the Austrian monarchy by far. The first amendments were made not before the 1960s and finally the present Forest Act was enforced in 1975.

Since earthmoving machinery became available after the second world war in Austria, more or less uncontrolled mechanized forest road building employing bulldozers on steep terrain led to serious problems in the 1950s. Consequently, regulations of a modern forest transportation system became the centrepiece of the Forest Act Amendment of 1962 enforcing general roading rules:

· Negative impacts on forest soils and stands must be minimized. The road density has to be limited depending on technical, economic and environmental considerations.

· Construction, maintenance and use of forest roads must not

- cause critical erosion,
- impede high water flow in torrents,
- enhance avalanches,
- cause imbalance of unstable terrain,
- influence the runoff in a negative way in critical watersheds.

· Forest roads must be planned by professional forest engineers, road building must be supervised by forest engineers or foresters.

· Individual approval by the forest authority with a formal procedure at the district level is required for forest roads planned in mountainous watersheds, and/or affecting protection forests, and/or interfering with public interests, e.g. public roads, railways, power lines, etc.

· Normal forest road projects outside of these limitations must be announced to the forest authority four weeks ahead of construction in order to check their location.

A by-product of this amendment was the legal framework of forest road associations needed for joint forest developments in areas subdivided into small farm forest properties.

These general rules described above are typical of the Austrian forest legislation. Contrary to detailed forest practices codes, which are recommended or enacted in many countries with a "young" forestry system, forest roading is regulated based upon more general rules and principles. However, the individual projects need a particular approval by the forest authority so that various details can be adapted to the varying local conditions.

Technical standards, e.g. road profiles, grades, drainage, as well as planning and construction methods are described in numerous textbooks, but are not legally enforced.

Additional environmental regulations

Though somewhat retarded compared to the United States, environmental discussions about forestry and in particular about forest road building commenced in Alpine Central Europe in the 1970s mainly initiated by NGOs in the course of the "Green Movement". In Austria this debate was soon transferred from the professional to the political level. To make things more complicated, there was an additional conflict involving the federal forest legislation and the provincial competence of preservation of nature. Central arguments and rebukes of the environmentalists in the partly heated discussions were:

· Foresters and forestry are too much oriented towards timber harvesting and economic profits disregarding environmental protection.

· Forest road building means negative impacts on the environment in general and on mountainous watersheds in particular. The existing federal regulations of the Forest Act are not sufficient to minimize these impacts, e.g. steeply increasing rates of erosion and stream siltation, forest damage, intersection of ecosystems and wildlife habitats, deterioration of scenic values (and so on), so that additional environmental restrictions are required.

Though the forestry side tried to defend its position, the public opinion and finally the provincial administrations adopted the environmental stance. Consequently, additional environmental restrictions were enacted in most of the Austrian provinces in the 1980s so that there is a dual approval system for forest road projects at present.

Since the tempers of the warring factions have cooled down, the effects of these decisions can impartially reviewed:


· The discussion between foresters and environmentalists led to new insights on both sides and mutual understanding in some way. While the forest party got a better understanding of complex environmental considerations, the environmentalists realized that forest utilization and development does not necessarily mean environmental deterioration and forest destruction. Consequently, multidisciplinary cooperation has largely replaced one-sided arguments.

· The conflict initiated a better planning quality of forest development projects as well as integral comparisons of development options, e.g. skyline yarding versus a dense road net on steep slopes.

· The previous trend to employ excavators instead of bulldozers on mountainous terrain was enhanced by the environmental restrictions imposed.


· The bureaucratic procedures are time-consuming and costly. There is a distinct disproportion between these more or less fixed costs and small road projects, e.g. of less than one kilometre in length.

· Losing the battle in the legal foreground, the forestry sector again lost some power and prestige within its own realm not only because of the legal overlay of environmental restrictions but also because all improvements achieved by the practical work of foresters now are attributed to environmental efforts in the public's opinion.

Approval procedures and conditions of the forest authority

Forest road projects, which need approval according to the Forest Act, are negotiated in local hearings by the district forest authority. In the case of an appeal, the forest authority at the provincial level has to decide. As far as feasible, the environmental cause is included in this hearing though it formally requires an extra procedure and approval. A regular permission based upon the Forest Act contains the following standard conditions:

· The road construction has to comply with the project regarding location and profiles. The minimum location requirement is a grade line staked and surveyed at about 20 m intervals. On difficult terrain the centre line and road profiles have to be additionally staked.

· Employment of excavators instead of bulldozers for earth and rock movement on steep ground exceeding 40 percent side slope is compulsory.

· Rock drilling and blasting has to be carried out carefully in order to minimize damage to forest stands and areas below the road. Along very steep and exposed road sections rock has to be removed by means of a hydraulic chisel mounted on the excavator's stick instead of the bucket. Normally, only sedimentary rocks, e.g. limestone or marl, are excavated by hydraulic chisels as most igneous rocks are too hard.

· A surplus of cut material (spoil), which occurs on steep side slopes exceeding 70 percent, has to be loaded onto dump trucks to be hauled to safe deposit areas. In many cases, however, a surplus of blasted rock or gravel can be economically used for the base construction. Depending on the type of rock, mobile rock crushers can be a viable option.

· Road slopes must be stable. They have to be shaped to the natural repository angles of the material. On steep slopes a trench cut along the lower fill edge should serve as fill foundation. Rocks and boulders are placed in this trench as additional revetment by means of the excavator. Long road slopes must be subdivided by berms in order to intercept surface runoff and to facilitate revegetation.

· Some diagonal berms across long road slopes should serve as foot tracks to make adjacent forest areas easily accessible by forest personnel.

· All road slopes subject to erosion must be revegetated by means of appropriate methods as soon as feasible in order to reduce the high rate of initial surface erosion. Usual methods are manual sowing of grass and legume seeds on easy ground, hydro-seeding of long road slopes on steep terrain, grass and hay mulching on sterile soils, and additional planting of alders and willows on wet and unstable ground.

· Immediate drainage of the construction site is compulsory to prevent road failures, landslides and serious erosion. The road drainage system must be closely adapted to the natural drainage system in order to interfere with the natural drainage patterns as little as possible. Therefore, the location of culverts is a critical element of roading. The minimum diameters for cross culverts (ditch relief culverts) are from 30 to 40 cm; their distances vary from 80 to 150 m depending on rainfall, subgrade erodibility, and road grades. The dimensions of stream culverts have to be individually designed depending on a 50-year flood event. Culvert inlets have to be protected against clogging and siltation, outlets against erosion by means of energy dissipating devices, e.g. stone riprap or timber crib.

· Embankments of critical stream crossings, in particular of deeply intersected torrents, should be kept as low as feasible by means of fords combined with a culvert for the normal water flow. The ford embankment must be stabilized by means of revetments, e.g. boulder riprap, timber crib, concrete walls, in order to withstand the forces of high floods and mud flows.

· Landslides in the course of the construction site must be immediately stabilized.

· Gravel pits opened for road construction must be revegetated after completion of the road.

· Intersections with public roads and foot trails must not hinder their original use.

Approval conditions of the nature conservation authority

Despite differences between the provincial legislation on the conservation of nature, there are some general principles in common:

· Overall objectives of the protection and preservation of nature and landscape with their indigenous environments in the interest of the public.

· Detrimental interference with nature and landscape, in particular environmental deterioration, habitat encroachment, and impairment of recreational and scenic values is prohibited.

As mentioned above, local hearings for forest road projects are often combined with the forest proceedings to provide for mutual information as well as for an integral approach. Additional conditions of the authority for the protection of nature are:

· Proof of an optimized development project by means of evaluating several options. In general, the road density has to be minimized in favour of mobile skyline yarding systems.

· Limits of road widths, e.g. a maximum subgrade width of 4 m. Turnouts are permissible only at insensitive locations.

· Protection of wet areas and specific wildlife and/or plant habitats.

· Protection of landscape and scenery by means of a road alignment that is well adapted to the terrain. Clear-cut restrictions along the road in order to reduce its visibility along exposed sections.

· Stream protection by means of buffer strips and silt traps.

· Immediate revegetation of road slopes with indigenous plant species.

Promotion of forest road building

In Austria the promotion of forestry by means of federal and provincial funds is based upon the Forest Act in Austria. Consequently, forest road projects are promoted through financial contributions and professional support. The main objectives of the promotion policy are:

· enhancement of the various forest functions;

· provision for an integral development planning and a good construction quality through professional advice in the interest of careful forest management as well as of environmental protection.

The Federal Promotion Guidelines contain numerous rules derived from practical experience over decades:

· Individual road projects must be planned within the framework of a general development plan.

· The road density has to be limited according to economic and ecological constraints and limits. For instance, 80 m/ha in small farm forests are regarded as maximum.

· Cooperation of neighbouring forest owners is required to avoid narrow serpentines (zigzag alignment) on mountainous terrain.

· Construction cost exceeding US$ 50/m must be justified.

· Construction methods have to comply with the practical rules and legal conditions discussed above.


Maximum 45 percent of the construction cost. Depending on limited funds the mean rate presently is about 35 percent. The maximum length of a subsidized project is 3.5 km a year.


Special loans with a low interest rate of about 3 percent additionally support the financing scheme of forest road projects.

Practical experiences in planning and building forest roads

1. Road spacing

Road spacing and locally feasible skidding techniques are interdependent. Under Austrian conditions road spacing varies from 200 m to 400 m depending on steepness, forest ownership and available skidding equipment.

Figure 1. Road spacing scheme for small private forests in Austria

2. Road alignment on steep terrain

While serpentine alignments are unavoidable in mountainous terrain, the number of switchbacks in a road course must be reduced to a minimum. Zigzag roads with too short distances between switchbacks are not only ugly and difficult to travel on but are sources of landslides and erosion on steep slopes. Therefore, cooperation between different small landowners in favour of appropriate road alignment is regarded as compulsory.

Figure 2. Serpentine road alignment on mountain slopes

3. Practical specifications of forest roads

Design elements


Side slope

< 50%

> 50%

Roadway width

4.5 - 5.5 m

4.0 m

Single-lane width

3.0-3.5 m

3.0 m

Minimum radius

25 m

20 m

Minimum switchback radius

10 m

Minimum switchback lane width

6 m

Maximum grade

9 - 12 % (16 %)

Minimum grade

2 - 3 %

Switchback grade

5 - 6 %

Turnout width

3.0 m

4. Experiences in forest road construction

4.1 Clearing width

While the clearing width of single-lane roads should not exceed 10 m on level or gentle ground, it tends to increase on steeper slopes.

Side Slope

Clearing width parallel to slope

Cut section (m)

Fill section (m)

Total (m)

< 40%












> 70%



13- 19

4.2 Excavator versus bulldozer

The hydraulic excavator (backhoe) has replaced the bulldozer in forest road construction. While the bulldozer is still an economical option on easy ground, the excavator has improved the feasibility and quality of forest roads in steep terrain. The machine is very versatile, but training and professional know-how of the operator is of utmost importance for the result. Big boulders can be piled for retaining structures; excess spoil is loaded onto dump trucks to be hauled to deposit areas instead of being side-cast downhill. Organic topsoil is removed in front of the machine and spread on the fill slope in order to reduce erosion and facilitate an early revegetation.

Figure 3. Backhoe work on steep ground

4.3 Drainage

Provisions for road drainage are essential for road maintenance and erosion control. Based on experiences in the Austrian Alps, the minimum diameter of normal cross culverts should be 40 cm rather than the usual diameter of 30 cm. At crossings with watercourses environmentalists prefer fords to culverts, since the latter interrupt the water ecosystem. In critical torrents, however, a culvert for the normal runoff with a ford for high floods is recommended from a practical point of view.

Figure 4. Culvert with protective structures across a watercourse

4.4 Base course

On weak, clayish subgrades the base course is the most expensive element of forest roads since it needs around 3 m3 of gravel per road metre and may cost up to 70 percent of the total cost. Long-distance transport of gravel is not only costly but is also a heavy burden in the very sense on access roads and the environment.

Therefore, several material saving options should be considered depending on local conditions:

· Recycling or processing of local material wherever feasible.

· In cold climates the base should be constructed during frost periods to prevent subgrade deformation and to save costly gravel.

· A polypropylene fabric layer prevents clay intrusions between subgrade and base course.

· Subgrade stabilization by means of quicklime.

4.5 Vegetative treatment of road slopes

Early revegetation reduces erosion considerably. Therefore a vegetative treatment by means of hydroseeding and mulching has become a standard procedure in Austria. Additional planting of alders and willows stabilizes wet and unstable road slopes.

Figure 5. Vegetative treatment of unstable road slopes for erosion control

4.6 Roads along watercourses

Watercourses and their adjacent environs are sensitive and vulnerable. Therefore, forests on steep riverbanks are generally declared protection forests by the Forest Act in Austria. Moreover, environmental regulations prescribe buffer zones on both sides of rivers and creeks as well as around lakes in the provinces.

Adequate buffer strips of 15 to 30 m in width with silt traps from logging residues are required in roading and logging along watercourses in order to protect them against erosion and sedimentation. Early cooperation of foresters with biologists and fishermen is recommended for well-adapted results already at the planning stage.

Also wet areas, e.g. bogs and swamps, are protected by the environmental legislation in the provinces and are generally off limits for logging.

Figure 6. Buffer strip along a forest road


Bundesministeriumfür Land- und Forstwirtschaft. 1994. Österreichischer Waldbericht. Wien.

FAO. 1989. Watershed management field manual. Rome.

Österreichische Bundesforste. 1994. Jahresbericht. Wien.

Sedlak, O. 1982. Types of roads and road network under difficult mountainous conditions and its relation to operational cable systems. ECE/FAO/ILO/IUFRO. Oslo.

Sedlak, O. 1985. Mountain forest roads in rural communities of Alpine Central Europe. IX World Forestry Congress. Mexico.

Sedlak, O. 1994. Forest harvesting and environment in Austria. FAO/IUFRO Meeting of Experts on Forest Practices. Feldafing, Germany.


Some Facts about Austria

Austria is one of the smallest but most densely forested countries in Central Europe. The country is landlocked and has no direct access to the sea. Neighbouring countries are Switzerland, Germany, Czech Republic, Slovakia, Hungary, Slovenia, Italy (clockwise from west).

1. Area, topography, climate

Total area: 84 000 km2

The orographic features are characterized by the alpine mountain range stretching from east to west. There is a great variety of geological strata and parent rocks, e.g. granites, gneiss, schist, limestone, marls, sandstone.

The climate is moderate and transitional from continental in the east to maritime in the west. The eastern and northern regions of the country have a yearly precipitation of some 500 to 800 mm, the western and mountainous regions get mean rainfalls of about 900 to 1 500 mm a year.

2. Population, socio-economic conditions

Population: 7.8 million
Population density: 93 per km2

Population in the economic sectors: 5 percent agriculture and forestry, 28 percent industries, 40 percent services, 27 percent pensioners and others. The total labour force is around 3.5 million.

Austria is not very rich in natural resources but has a well-developed economic and social system with a GDP of about US$ 17 300 per caput. While agriculture and forestry contributed 15 percent to the GDP in 1955, its share shrank to about 2 percent in 1995!

The forest resource

Forest land: 3.9 million ha (46 percent of the total area, 0.5 ha per caput). The forest area is steadily increasing by some 2 000 ha/a due to afforestation of non-productive agricultural land. Boreal forests of mixed and/or pure stands of spruce, fir, pine, larch, beach, maple, oak, alder, etc., find good growing conditions. The timberline of the mountain forests is at 1 600 to 1 800 m asl.

· Commercial forests: 3.1 million ha (80 percent)

· Protection forests: 0.8 million ha (20 percent)

· Main tree species: 70 percent conifers (predominantly spruce), 30 percent broadleaved species (mainly beech).

· Total standing volume: 972 million m3 sob

· Mean standing volume: 314 m3 sob per ha in commercial forests.

· Mean increment: 9 m3 sob per ha a year.

At present, however, Austria's forest resource is underutilized because of economic and technical reasons. The current harvest is around 18-20 million m3 sob, while the total increment is estimated at 31 million m3 sob a year.

A dense forest road net of more than 100 000 km was constructed in Austria after the second world war. The total road length within the forest land is around 140 000 km including public roads. The mean road density is 45 m/ha in commercial forests and 9 m/ha in protection forests including effective public roads.

The forestry system

Forest ownership:

55 percent small private forests (< 200 ha)
32 percent private estates (> 200 ha)
15 percent federal forests


At present, about 3 600 professional foresters are on the job in Austria. 50 percent are employed in the production sector of forest enterprises (mean value about 1 700 ha per caput) and 50 percent are in the service sector (Forest Service and other organizations).

Education and training:

1 University, 2 Forester Schools, 1 School for Forest Guards, 2 Forest Training Centres for vocational and post-graduate training.

The labour force of forest workers shrank from 8 600 in 1984 to about 5 000 in 1993 because of mechanization and social changes.

Labour costs and productivity:

Like elsewhere in industrial countries cost of human labour has become expensive. The wage level of piece-rate work is around US$ 14 per productive hour. Total cost is around US$ 30 an hour allowing for non-productive time and social benefits. The productivity is about 1.4 m3/hour in thinnings and 2.1 m3/hour in final cuts of the Federal State Forests.

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