* Forestman & Associates Pty Ltd, P.O. Box 104, Samford 4520 Australia, Tel/Fax: ++(61 7) 3289 4245, E-mail: firstname.lastname@example.org
The planning and construction of forest harvesting roads is a major and expensive operation that is critical to the orderly flow of logs. In tropical environments, road development has to contend with difficult terrain and high and protracted rainfall. Traditionally, logging roads have tended to use high-impact construction methods featuring wide clearing widths, major earthworks and relatively crude construction standards. The justification for such practices has commonly been on the basis of economic and operational needs. Poorly located, constructed or maintained roads are inefficient and can cause major soil and water hazards with serious and long-term social implications to affected communities, which may be distant from the site of the actual road.
Codes of practice have aimed at setting basic standards to reduce these adverse impacts whilst still meeting operational and other needs. Such new standards are often opposed by the timber industry as being impractical and uneconomic. Experience in code development in tropical Australia and a review of harvesting practices in the South Pacific suggests that proper road construction, sound environmental management, beneficial social outcomes and operational economics need not necessarily conflict. With few exceptions, good practice can achieve production, social and environmental management needs economically.
While acknowledging the many examples of good roading practice, this paper concentrates on the problems that can occur and offers some basic, but key points that are considered fundamental to making forest harvesting roads effective, economic and environmentally responsible for all parties concerned.
THE ROADING CHALLENGE
The objective of forest roading is to provide a road network that achieves economic production whilst meeting environmental and social needs. Essential considerations are:
1) Production needs: The primary purpose is to provide a road network of a standard and density that guarantees operational access and the timely and economic delivery of the required volume of wood. Access requirement is relatively short term. Economics must consider both the direct costs of planning and constructing an optimum network as well as the indirect costs and production ramifications caused by impassable roads, slow haul speeds, accidents, vehicle damage and landowner disputes. Industry must address the total road economics.
2) Social needs: Logging roads may be required for other purposes well after logging has ceased. Forest services may require access for silvicultural operations. Governments and communities seek road infrastructure to serve the access and development needs of an area. The need is usually long term and may be at odds with harvesting requirements and logging road development.
Landowners may obstruct or prevent roading for personal, cultural or financial reasons.
Community demand for roads may be without essential planning and have unreasonable expectations as to the road standard, particularly bridges that can be afforded by the industry. The logging roads may not be appropriate to community needs and cause social problems and undesirable development.
The community may have no capacity, skills or intent to provide essential and ongoing road maintenance.
Despite this, community approval is often essential to the continuous and uninterrupted use of roads for logging.
3) Environmental needs: Roading can be a major and ongoing cause of adverse environmental impact. Impacts such as overclearing, visual scarring and accelerated land instability can have serious social and forest-sustainability ramifications. The primary problem tends to be soil loss and watercourse sedimentation. Roads and tracks are the sources of major sedimentation of watercourses with direct and ongoing impacts on community water supply and aquatic habitats. Environmental needs must be identified and then managed to avoid damage. Environmental concerns need to be addressed if logging is to remain acceptable.
The optimum forest road has to balance these needs and constraints in a way that is economic for the timber industry. This requires effective and economic planning, construction and maintenance of roads.
Key: If you do not know the real costs you cannot determine if you are economic
The costs and economics of road development and use are of primary importance to the overall economics of a logging operation. Various figures are often quoted for different standards of roads but unless the nature of the road and the basis for the figures are known, these costs have little meaning.
During a review of logging standards in the South Pacific, logging managers appeared rather vague on the question of roading costs. This may have been corporate policy - not to reveal costs. However, it is suspected that many simply do not have the accounting procedures to determine the real costs of roading (or indeed any other element of harvesting) other than an overall operational cost per cubic meter. Further, observation of the often considerable range of equipment standing idle and the apparent inefficient organization and operation of equipment suggests that there are likely to be significant savings if the inefficiencies could be clearly identified and corrected.
If you do not know the actual costs (direct and indirect) of each component of road planning, construction and use, there is no way to determine:
if you have an optimum economic outcome;
where to concentrate supervision or resources to achieve further economies; or
whether acquisition of equipment or adoption of different construction methods is viable.
Too often, suggestions for improvement (e.g. compaction) are rejected on the basis that it will cost more. The matter can only be evaluated by analysing whether the investment achieves greater savings in direct or indirect costs in road construction or use.
Several points may be relevant:
1) The costs of roading must consider all elements. This will require that companies have appropriate accounting practices. Various texts can provide guidance on cost calculation to include all essential aspects and permit proper analysis and management of roading. Such procedures can be complicated. An alternative is to conduct studies on specific components to derive a reasonable cost estimate that can guide management.
2) Costs increase dramatically with road standards. Costs per kilometre quoted for major roads tend to be double those of minor roads. Conversely minimal-standard haul roads are relatively cheap. Clearly a properly designed road network, with each standard of road used in its appropriate place, will reduce and optimize total costs.
3) Roading costs do not only relate to the direct costs of labour, equipment and material used in construction and maintenance but also to:
cost and production impact of delays caused by road failures or impassability;
cost and production impact of haulage over the current road standard; and
cost and production impact of truck damage, repair and unavailability.
These indirect costs can be substantial and need to be factored into decisions on road standards, construction methods and maintenance intensity.
Figure 1. Major direct and indirect costs associated with logging roads
PLANNING FOR EFFECTIVE, ECONOMIC AND ENVIRONMENTALLY RESPONSIBLE ROADS
Key: Time spent on effective planning can be an economic advantage
The initiation and ongoing development of a logging operation has to contend with pressure for early and continuous production. This imperative may be at odds with the time needed to plan effectively. There is a common tendency to build with limited planning. Planning requires good survey and mapping information. Unfortunately, adequate maps may not be available. Aerial photography or inspection can be particularly useful but require training in interpretation. Global positioning system approaches can be useful for ground surveys, but require training and equipment Time and resources spent surveying and planning should be weighed against the costs and problems caused by inadequate planning:
Road alignments that are unworkable because the full length and practicality were not surveyed and roads had to be realigned or relocated.
Tortuous alignments increase road lengths and incur an ongoing production penalty in haulage time and cost.
Alignments that involve excessive side-cutting or watercourse crossings at great cost.
Undesirable grades that limit use, compromise safety and results in vehicle damage and production penalties.
Roads that do not tap the best resources and require long skid distances.
Landowner disputes or road use disruption because of conflicts over social or cultural issues.
Planning, or the lack of it, sets the economic base of road construction, use and maintenance. Time spent in effective planning can result in substantial and enduring rewards.
Key: Planning should provide an effective and economic network
The road system should involve an appropriate network of major, minor and haul roads of progressively decreasing width and standard to achieve the production needs with minimum total cost and environmental impact. Because costs and impacts tend to increase with both road standard and density, total efficiency will depend on optimal planning to meet the need with the minimum necessary infrastructure with overall economy.
Road standards: Codes of practice generally specify basic road design standards. The standard of the road at a particular point should reflect its purpose, life and design capacity in terms of volume and haulage speed. Observations in the South Pacific reveal that road standards, particularly for minor and haul roads, tend to be excessive in width and the extent of earthworks. Unnecessarily wide clearings for roads are more expensive, take longer to construct and have a greater environmental impact. It is suggested that while major haul roads should not be underbuilt, greater use can be made of cheap and low-impact haul roads. Several elements are worthy of consideration:
Road classification: This must have practical meaning and guide industry as to the required minimum road standards at a particular point. In the Asian-Pacific region, volume per week is used but this can be difficult to predetermine. The classification system must relate to need and it may be more meaningful to express this in terms of total volume, which is easily calculated prior to logging. If this approach is used then the point at which haul roads should become minor and then major roads can be simply determined by both industry and the forest services. The question of classification needs closer analysis and specification.
Belief in haul road capability: Where there has been a tradition of wide roads there can be great concern as to the practicality of the minimum standard of a haul road. Experience in Australia under conditions equivalent to most tropical situations demonstrated that haul roads with very narrow clearing widths and minimal formation can operate effectively and economically if appropriately managed and used.
Clearing width: Clearing width should be kept to a minimum needed to construct the road construction, permit surface drying and provide sight lines. There is a common belief that road clearings must be very wide to permit sun drying. Road surfaces need exposure to sunlight. However, the width required to effectively achieve this can be quite narrow due to the high angle of the sun in the tropics. Some standards specify a permitted maximum width. Under this regime, logging companies tend to automatically clear the full permitted distance. The Code of Practice for Forest Harvesting in Asia-Pacific standard of one meter beyond the earthworks is more realistic (FAO, 1999).
Extent of earthworks: It is common in the lesser elements of the road network to see excessive earthworks and lowering of the road into the terrain. Apparently this is caused by road builders cutting down to find a hard surface. This is time consuming and costly, complicates drainage and eliminates the possibility of regrowth of trees after logging. Given the limited use and life of such roads, it may be preferable to minimize excavation and utilize compaction to achieve a load-bearing surface.
Roading density: The issue of roading density relates to the spacing of minor and particularly haul roads. Whilst the subject of many texts, the planning of an optimum road density can be both complicated and difficult. The objective is a density/spacing that results in the lowest combined cost of roading and skidding. The basic considerations are terrain, volume per hectare and relative roading and skidding costs. If loggers do not know these costs, there is no way that an appropriate density can be planned. The cost of excessive or inadequate road density can be significant in terms of production costs and time.
Road standards and density should be the minimum necessary to meet needs economically.
Key: Planning integration with logging needs
Planning and road construction must meet the logging needs and be timely. Firstly, it is not uncommon to see roads and landings constructed, often with extensive earthworks, and then remaining unused, with the road becoming a massive skid trail. There may be weather-related reasons for this but clearly the time, costs and impacts of such works are considerable. The plan must meet the operational need.
Secondly, planning and road construction must be sufficiently advanced and ahead of logging to avoid haulage on unfinished roads. Poor planning, operational pressures and weather can result in haulage being attempted on unfinished sections of roads. This is not only difficult because of bogging and the need to tow trucks through the area; it can also have secondary adverse implications for skidding and loading with undesirable landings and skid trails being developed to overcome the problem of the unfinished road. Roading must be ahead of the needs, and planning should provide areas that can be worked in wet weather or where roading is delayed. Smashing through roads to meet the production target may yield the logs but can be hugely expensive because of low productivity, damage to roads and equipment, safety and the environment.
CONSTRUCTING EFFECTIVE, ECONOMIC AND ENVIRONMENTALLY RESPONSIBLE ROADS
Key: Construction to achieve the fundamentals of effective roading
The engineering principles of road construction are well known. While forest roads cannot generally afford the detail, finesse and cost applied to public road engineering, they must at least achieve the fundamental requirements for a successful road pavement. Basically any soil can support any load provided it is compacted (to achieve strength) and it is kept dry (to prevent water entering the road and weakening it). A forest road must have a good foundation and a water-resistant or shedding surface. Unless a road achieves these two factors adequately, it will fail. An effective road will (i) be constructed from the base upward in layers that provide a good foundation and (ii) be provided with an effective surface. Too often, due to pressure to provide access, the forest road builder ignores these fundamentals and attempts to solve the lack of load bearing capacity by excessive clearing, sun drying and gravelling. If the road is not delivering the production because of bogging or other failures, the chances are the fundamentals have been overlooked. In the long term this is poor economics that stops or delays production, reduces travel speeds, damages trucks and ultimately costs more than good construction.
Compaction will improve almost any soil by increasing road strength and providing a smooth and strong running surface. Compaction of the subgrade and base course is essential if the road is to carry the design load without failure that will result in production inefficiencies, delays and costs. The subgrade should be compacted and fill material placed in layers and compacted by an appropriate number of machine passes. Effective formation and compaction will require the use of less gravel material with significant savings in the cost of extracting, carrying and spreading gravel. Compaction of the surface is equally, if not more, important than compaction of the subsurface. Surface compaction creates a strong pavement that can carry and distribute wheel loads over a greater area. Additionally, optimum compaction tends to seal the surface, limiting or preventing water entry. This has the advantage of:
a smoother running surface permitting higher speeds and reducing vehicle damage; and
less surface erosion (increasing road life and reducing maintenance costs), dust formation and sediment production.
Consolidation by leaving the road surface to settle over a period of time is a poor substitute for compaction. It is strongly suggested that effective compaction is worth the cost.
Road drainage must protect the road from surface and groundwater. Water entering the pavement or subgrade weakens the structure making it more susceptible to failure. Road drainage is fundamental to road life and effectiveness and two basic elements are involved:
1) Surface drainage should drain road surface water and divert this and other water from adjacent areas away from the road formation. First, surface drainage is provided by shaping and compacting the road profile to shed water in either a crowned, outsloped or insloped formation. The crossfall should be in the 4 to 6 percent range to shed water without making driving difficult or dangerous. The correct profile established in construction should be maintained by grading and recompaction. Second, a system of table, turnout and cross-drains should direct water away from the road area.
2) Subsurface drainage protects the road against water that has entered through the road surface and subsurface water that enters from surrounding areas or the water table. The objective is to prevent the road from becoming saturated in a zone between the surface and a level approximately one metre below the surface. This is achieved by surface drainage, compaction of the subgrade and pavement, and drainage or road elevation to keep the road above the level of the local water table.
Failure to provide effective drainage will result in:
loss of the road through wash out or slumping resulting in road closure;
failure of the road pavement, affecting production and production economics;
erosion of the pavement with increasing surface roughness and need for resurfacing; and
high soil loss leading to stream sedimentation and serious environmental impacts.
Lack of effective road drainage is a major problem. Primary issues are:
lack of compaction;
lack of effective surface profiling and the continuing maintenance of this profile;
inadequate depth and capacity of table drains;
inadequate turnout of table-drain water;
inadequate number and size of cross-drainage and structures;
improper grading practices with water not being drained from the road surface;
inadequate maintenance of drainage systems;
blading off the road surface because of poor construction; and
lack of fill-protection or sediment-trapping systems.
The generally inadequate provision of cross-drainage is a major concern. Culverts and pipe cross-drains are expensive and time consuming to construct. Rollover water bars and inverts can be a simple and inexpensive alternative in some cases.
There is ample advice in the literature on the design and construction of effective and appropriate drainage and sediment trapping devices.
The combination of effective compaction and good drainage will result in an effective road. Conversely, inadequate compaction or drainage will, at minimum, cause inefficiencies and, in many cases, road failure. It is all too common to see road surfaces being bladed off to make them workable. This is not only expensive, but is a short-term measure that removes the road pavement and destroys the drainage system with disastrous environmental outcomes. It is also a certain sign that engineering fundamentals have not been achieved.
Key: Culverts and crossings need care
The construction of culverts and crossings is one area where codes require industry to undertake additional work for very important and sound environmental reasons. Watercourse crossings are locations where road construction can cause significant damage and sedimentation of streams. Important factors are:
Sites for crossings should be excluded from initial alignment clearing and disturbance to avoid soil being bared and debris being pushed into the watercourse.
Crossings should be planned and set out to preserve vegetation, except on the actual crossing alignment. Clearing should be confined within this area.
Culverts and crossings are best constructed with an excavator because it is almost impossible for the work to be done by bulldozer without excessive disturbance. Excavators can easily complete all operations without entering the watercourse.
Key: Gravel is expensive and gravelling should be managed
Gravelling is an expensive operation and gravel may not be available, or may be of poor quality.
The use of gravel should be based on need and relate to road standard and design life. Gravelling should be avoided on temporary roads.
Effective compaction and formation may reduce the need for gravelling. Gravel may not fix the problems caused by poor compaction and formation.
Forest roads cannot afford detailed analysis of gravel requirements and the sizing and mixture of gravel materials applied to public roads. However, some attention to these factors can yield benefits:
1) Size material: Firstly, the minimum gravel depth should be about 1.5 times the size of the largest particle. The use of unscreened materials can require greater volumes. Secondly, it is common to see unscreened material being hauled considerable distances only to be dumped and the larger materials graded off the road. Quite simple screens can be erected at the gravel extraction site to roughly size material. The appropriate size can then be dispatched to the appropriate course. Bottom courses can use large materials whereas surface layers should use finer materials to achieve a smooth running surface. Even simple screening can result in significant savings, avoid wastage and achieve an improved road surface.
2) Formations should be smoothed prior to gravelling to reduce wastage caused by having to fill irregular surfaces.
3) Compaction should be used to consolidate the gravel and increase its effective life.
Key: Construction must be planned and actively supervised by competent people
Road construction is a complicated and staged process that requires all phases to be achieved in an integrated fashion with minimum works if the road is to be built at the least cost possible. Unfortunately, road construction is commonly not supervised effectively, resulting in:
slow, ineffective and uneconomic construction;
excessive clearing, earthworks and wastage of valuable fill material; and
unnecessary and excessive environmental damage.
Unless effective supervision is applied, an effective and economic road will not result. Effective supervision requires that the supervisor:
knows the roading plan and the logging priority;
understands road construction and the management of machinery;
sets out the centre line and the boundary of clearing, earthworks and exclusion areas;
manages the orderly and economic progression of each phase of construction;
matches equipment and resources to tasks and operational needs;
ensures that operators know what is required and are aware of problems;
actively supervises and directs operations; and
concentrates efforts in priority areas.
Responsible environmental management must be applied throughout the construction phase. Damage must be avoided as repair is usually difficult, costly, impractical or simply not done. Supervision must be aware of, and avoid, works that pose environmental threats.
Key: Equipment must be appropriate
Ideally road construction should have a range of equipment available so that each task can be achieved in the most efficient way. Equipment is expensive. For small operations or companies, the capital cost of acquiring bulldozers, graders, compactors and excavators may appear to be prohibitive. However, using bulldozers only for construction is inefficient. Larger companies have a greater capacity to utilize appropriate equipment with savings in earth movement, drainage, formation and gravelling.
Bulldozers remain the major multi-purpose tools for clearing and earthworks. The type of bulldozer used should be matched to the clearing and earthmoving needs. While bulldozers can do many tasks, they may not necessarily perform these efficiently and it may be more economic to invest in purpose-built machines (e.g. graders for formation) than continue using bulldozers.
Excavators are very versatile and effective construction equipment with significant advantages over bulldozers for excavation and placement of earth, battering of slopes and particularly for the construction of watercourse crossings and culverts. This efficiency tends to increase as conditions become more difficult (e.g. waterlogged). Their use is strongly recommended.
Graders can spread material and form road surfaces to a high standard and most efficiently without the waste, inefficiency and poor standards resulting from the use of bulldozers.
Compactors, whether towed or self-propelled, are important tools and their effective use can result in significantly improved standards and overall and long-term savings. Compactors should be matched to the soil type. Steel vibratory drum rollers are the most common. Other machinery including graders, loaders and trucks can assist in compaction, but this requires that the equipment varies the running track to compact the entire road surface. However, in general, this cannot match purpose-built compactors because ground pressures are much lower and the compaction is uneven. Compactors must be used properly, rolling the earth progressively from the edge to the centre of crowned roads with correct engagement and disengagement of the vibratory mechanism to achieve a uniformly strong and smooth surface.
Trucks and scrapers: Where soil movement distances are short (i.e. less than 50 metres), bulldozers will perform quite effectively. As distances become longer, bulldozer use becomes increasingly slower, uneconomic and wasteful in terms of lost materials. Trucks and scrapers become more economic with distance.
Key: People must be trained and managed
The effectiveness and economics of road construction are highly dependent on the skill and attitudes of the people involved.
Forest service staff should inspect, identify problems and positively contribute to road construction. They cannot do this unless they have a practical understanding and experience of road construction and equipment management. It is not uncommon for forest officers to avoid inspection because they do not know the process or criticize without being able to provide answers. Training is generally needed and forest officers should have the knowledge to intervene in a situation before it becomes a problem. The industry has the right to expect that the forest officers are experienced and can provide helpful and productive suggestions. Forest officers must have the skills to be able to assess plans and evaluate road-construction operations.
Operators must be trained, skilled and experienced in machine operation and construction and maintenance techniques. Essential elements are:
1) The operator must be trained in correct techniques. This may take time.
2) The operator must be given the time to practise and gain experience so that new skills can be applied with economic speed.
3) The operator must have incentives to encourage application of best practices. Incentives may be in the form of financial reward, security of employment or prestige.
4) Operators with good skills should be encouraged by seeking their advice and by allowing them to operate without unwarranted and demeaning supervision.
Training will only be effective where there is a corporate employment policy that seeks and values a core of skilled operators. Too often the operator is regarded as expendable and easily replaced. Such attitudes do not result in good operation and can prove to be expensive in the long term.
Investment in skills training can achieve:
reduced machine damage and increased machine life;
better and more effective roads with gains to haulage productivity; and
USE AND MAINTENANCE: KEEPING ROADS EFFECTIVE
Roads must be used and maintained in a way that preserves their lives and efficiency.
Key: Roads should be used wisely
There are times when roads should not be used. Under wet conditions, any attempt to haul timber may be counterproductive. Under these conditions the road is most sensitive to damage:
Production will be slow, unsafe and counterproductive in terms of road and vehicle damage. Industry must provide for wet weather areas and log stockpiling to overcome these events.
Use of the road will provide the highest threat of soil loss and stream sedimentation. Continued use with increased rutting will only worsen the situation.
The Code of Practice for Forest Harvesting in Asia-Pacific provides operational restrictions for felling, skidding and road construction but provides no guidelines for haulage. This oversight may need correction.
Key: Maintenance must be applied and effective
It is all too common to see a well-aligned and constructed road become ineffective, if not impassable, because maintenance has not been applied or is applied properly. Road systems must be maintained to ensure their efficiency and keep drainage and sediment control systems operative.
Proper maintenance requires a concerted inspection program with regular checks of drainage systems and early correction of faults.
Maintenance should be applied on both a preventative and demand basis. Proper road use requires a pro-active maintenance program based upon timely inspection of road conditions. Such checking should not only guide maintenance but should also be part of a learning process to analyse and correct failures. A supervisor should be responsible for regular inspections of road surfaces and drainage systems to identify wear, and plan for repair. Timely maintenance can save costly repairs and avoid inefficiency in the road system. The objective of effective maintenance is to maintain the efficiency and life of the road by:
maintaining a good riding surface;
maintaining effective surface and subsurface drainage; and
correcting safety hazards to vehicular traffic.
A good operating surface will improve haulage speeds and reduce vehicle damage. It requires effective surface grading to smooth ruts and compact the surface to enhance the life of the grading. Drainage maintenance requires the surface profile to be restored as well as the table, turnout and cross-drains. Water must be able to freely drain from the road surface and then be managed in the side-drainage system.
While surface smoothing is usually done well, often little attention is given to the restoration of drainage systems. Common problems are:
Grading material from the road to the sides instead of returning material to the road.
Not using compaction with grading with the result that re-profiling has only short-term benefits and surface loss is increased.
Surface grading creates a rill along the road edge and prevents surface water from entering the side drains.
Not removing road edge vegetation, which stops free surface drainage and confines water to the road.
Not reopening table, turnout and cross-drains.
Grading demands knowledge of the objectives, timing, skills and correct techniques in application. Good grading is more than just temporarily smoothing the surface.
Road systems should be subject to practical forms of assessment of effectiveness and environmental management deficiencies:
Cost assessment needs to cover total costs of skidding and haulage, in addition to the direct road construction and maintenance.
Environmental effectiveness can be assessed via audits or monitoring programs. The Queensland Department of Natural Resources in Australia has developed auditing procedures and practices for their Native Forest Timber Production Code of Practice. Alternatively, or in addition, forest officers should utilize indicator-type monitoring systems soundly. Provided these are well designed and used cooperatively and positively, they can be useful tools for both government and industry. The aim is to identify and correct problems.
The need to get smart: Industry can react to the imposition of new standards in one of two ways. Firstly, it can fight, object and resist. This is rarely sensible or productive unless the standard is in error. The alternative is to accept and try to meet the standard. In Queensland, the introduction of a code was strongly opposed as being uneconomic. Two years later, the objections had disappeared. Industry quickly realized the value of the techniques and avoided problems or the need for corrective work - all parties gained.
Seeing is believing: Calls to change the modus operandi are often opposed because there is little or no experience in implementing new practices and there is disbelief in their effectiveness. There can be great value in visiting conforming operations and seeing how they work. Often lack of understanding or experience results in an enormous waste of effort as people reinvent the wheel.
Given the costs, economic consequences and potential environmental problems associated with poor roads, there may be value in:
Collating road construction and management information. There are many appropriate texts, manuals and guidelines that can provide practical and relevant information on road construction. Preparation and publication of a list of useful information would be useful.
Training programs should be developed for roading supervisors, forest officers and operators to achieve similar benefits obtained from chainsaw and logging machine operator training. This should involve hands-on experience in equipment management and construction techniques. Development of road training is not a trivial matter given the need for access to land and equipment. Given the cost, such training may be best conducted on a regional basis.
FAO. 1999. Code of Practice for Forest Harvesting in Asia-Pacific. Food and Agriculture Organization of the United Nations, Bangkok.
Useful information from Queensland, Australia
Forest Codes of Practice - a range of forest codes of practice and other information has been prepared by the Queensland Department of Natural Resources.
Roads in the Wet Tropics - Queensland Department of Main Roads provides an overview of environmental management systems for sealed and unsealed roads in tropical situations.
Unsealed Roads Manual - Guidelines to Good Practice. A 1993 publication of the Australian Road Research Board providing design, construction and maintenance information.
Soil Erosion and Sediment Control - Engineering Guidelines for Queensland Construction Sites. A 1996 publication of the Queensland Division of the Institute of Engineers, Australia.
Forest Road Manual - a 2000 production of the Queensland Department of Primary Industries (Forestry).