Is Forestry Trunk Road Paved? (Explained)

Forests are vital natural resources that provide many benefits, such as timber, wildlife habitat, recreation, and ecosystem services like carbon sequestration and watershed protection.

Managing forests sustainably requires a transportation network to facilitate stewardship activities, fire control, and timber harvesting. But are the main forestry trunk roads paved or unpaved gravel and dirt roads? There are pros and cons to both paved and unpaved forestry roads. Let’s take an in-depth look.

Forestry roads, also called forest roads or logging roads, provide access to forested areas for management purposes. They consist of a network of main trunk roads that connect to smaller branch and spur roads. The main question is whether these trunk roads are paved with asphalt or concrete or left as gravel/dirt surfaces.

This article will examine the following about forest road surfacing:

  • The purpose and uses of forestry trunk roads
  • Reasons for paving or leaving unpaved
  • Advantages and disadvantages of each
  • Case studies and examples
  • Best practices for road surfacing decisions

Proper road surfacing is crucial for safe, efficient, and environmentally responsible forest management. Understanding the tradeoffs helps road managers make informed decisions.

Purpose and Uses of Forestry Trunk Roads

Forestry roads serve many vital purposes:

  • Timber harvesting – Transporting cut trees from the forest to the mill. Main trunk roads connect the logging sites to the highway system.
  • Fire control – Providing access for fire trucks and equipment to help suppress wildfires.
  • Recreation – Enabling public access for camping, hunting, fishing, hiking, bird watching, etc.
  • Ecosystem management – Access for conservation activities like thinning, invasive species removal, stream restoration, etc.
  • Research – Roads facilitate scientific study of forest ecology, wildlife, soils, hydrology, and more.
  • Administrative uses – Patrolling and monitoring of timber sales, grazing leases, mining claims, etc.

The main trunk roads are the “backbone” of the forest road network, facilitating these many uses.

Factors In Road Surfacing Decisions

Several key factors determine whether forestry managers pave trunk roads or leave them unpaved:

Traffic Volume

  • Higher traffic levels – More frequent heavy truck loads require paved roads to withstand wear and tear. Paving also reduces dust.
  • Lower traffic levels – Gravel or dirt surfaces are adequate for lighter, intermittent traffic.

Climate and Weather

  • Wet climates – Paved surfaces shed water better and resist erosion in rainy conditions.
  • Dry climates – Lack of rain allows unpaved roads to hold up reasonably well.

Soil/Terrain Type

  • Fine-textured soils – Prone to rutting and erosion from use when wet. Paving helps stabilize.
  • Coarse, granular soils – Drain better and resist erosion even when unpaved.
  • Mountainous terrain – Steep grades and switchback curves subject unpaved roads to damage.


  • Paving costs – Paving requires large initial investment but lower maintenance long-term.
  • Gravel road costs – Less expensive initially but requires frequent grading/resurfacing.


  • Clean Water Act – Paving helps reduce sediment runoff into streams from roads.
  • Dust control – Paving prevents dust from impacting air quality near populated areas.


  • High-use recreation areas – Paving provides a improved visitor experience.
  • Remote areas – Gravel blends better visually with natural landscape.

Advantages of Paved Forestry Trunk Roads

Paving main forestry trunk roads with asphalt or concrete offers several advantages:

  • All-weather access – Paved roads can be used year-round, even in wet conditions when unpaved roads degrade. This allows consistent management and timber harvesting access.
  • Higher traffic volumes – Pavement stands up to heavier truck loads and higher daily traffic counts without rutting or forming potholes.
  • Higher speeds – Paved roads allow safe travel at higher speeds compared to unpaved surfaces. This improves productivity.
  • Less sedimentation – Paved surfaces prevent erosion, protecting water quality in nearby streams. This complies with Clean Water Act requirements.
  • Dust control – Pavement prevents dust issues from impacting timber hauling, recreationists, wildlife, roadside vegetation, and nearby communities.
  • Lower maintenance costs – After the initial paving investment, maintenance costs are lower compared to frequent grading of unpaved roads.
  • Improved aesthetics – Pavement provides a cleaner, smoother appearance for high-use recreation roads.

Disadvantages of Paved Forestry Trunk Roads

Paving main trunk forestry roads also comes with some drawbacks:

  • High initial cost – Paving requires large capital investment in road preparation and asphalt/concrete costs. Beyond budgets in many cases.
  • Habitat fragmentation – Paved roads with higher speeds and traffic volumes can divide habitat and increase animal mortality.
  • Increased development – Paved roads provide easier access that can encourage more human activity and disturbance.
  • Heat absorption – Pavement absorbs heat and raises temperatures locally compared to natural ground cover.
  • Stormwater issues – Paving increases surface runoff which can concentrate water flows and cause erosion issues.
  • Visual impact – Pavement contrasts sharply with the natural landscape visually and can detract from remote area aesthetics.
  • Difficult maintenance – Repairing deteriorated pavement requires specialized equipment not readily available in remote forest settings.

Advantages of Unpaved Forestry Trunk Roads

Maintaining unpaved gravel or native surface forestry roads also presents some advantages:

  • Lower costs – Leaving roads unpaved significantly reduces upfront construction costs.
  • Stormwater infiltration – Unpaved roads allow more water infiltration into the ground compared to paved surfaces.
  • Flexibility – Gravel roads can be relocated or decommissioned more easily as needs change.
  • Habitat connectivity – Permeable soil surfaces pose less of a fragmentation barrier to wildlife movement.
  • Visual blending – Gravel roads appear more rustic and blend better visually with remote settings.
  • Cooler temperatures – Lack of pavement reduces heat absorption and temperature rise compared to asphalt roads.
  • Traction – Gravel and dirt surfaces provide good traction for vehicles even when roads are wet.
  • Dust mitigation – Watering and chemical treatments can reduce dust issues on high-traffic unpaved roads.

Disadvantages of Unpaved Forestry Trunk Roads

However, maintaining forestry trunk roads as unpaved also has some drawbacks:

  • Frequent maintenance – Unpaved roads require near-constant grading, gravel replacement, and repair to keep them in usable shape, especially with heavy traffic.
  • Erosion and rutting – Water and use wears away unprotected road surfaces leading to deep ruts, gullies, and impassable sections.
  • Limitations in wet weather – Prolonged rains degrade unpaved roads and can make them temporarily impassable. This disrupts timber operations and access.
  • Sedimentation – Erosion of loose road materials leads to sediment loading in nearby streams, impacting water quality.
  • Dust issues – Traffic on unpaved roads generates large dust clouds that settle on vegetation and impact air quality.
  • Lower speeds – Gravel and dirt roads limit safe travel speeds, reducing productivity.
  • Noise and vibration – Travel on unpaved roads generate more sound and vibration issues compared to paved surfaces.

Case Study Examples

Real-world examples help illustrate appropriate situations for paved or unpaved forestry trunk roads:

  • The Tongass National Forest in Alaska depends on floatplanes and boats for timber access, so most main forest roads remain unpaved native surface roads only suitable for high-clearance vehicles. The wet climate and minimal traffic do not justify paving costs.
  • The Green Mountain National Forest in Vermont contains many high-use paved roads to accommodate heavy logging trucks and recreational traffic. The paved roads reduce erosion and provide reliable access in this wet climate.
  • The Apache-Sitgreaves National Forest in Arizona contains hundreds of miles of gravel forestry roads sufficient for the dry climate, lower use, and remote setting. Paving costs are not supportable for the limited timber program.
  • The El Dorado National Forest in California has an extensive paved road system due to heavy recreational use, fire risk, and soil erosion potential. Paving reduces sedimentation, provides safer access, and meets user expectations.

Best Practices for Surfacing Decisions

When determining whether to pave forestry trunk roads, land managers should consider these best practices:

  • Conduct traffic studies – Measure current and projected traffic volumes and types. Paving may be justified for roads with regular heavy truck use or high recreation numbers.
  • Evaluate climate and soils – Roads on fine-textured, erosive soils in wet climates are good paving candidates. Well-drained soils in arid regions can support unpaved roads.
  • Consider regulations – Paving may be required to meet Clean Water Act, dust abatement, or other environmental rules in some areas.
  • Weigh costs – Compare paving costs against long-term gravel road maintenance expenditures. Paving may have higher initial costs but lower lifetime costs.
  • Assess infrastructure – Paving requires aggregate sources and equipment/crews capable of road preparation and asphalt or concrete work, which are not available in all locations.
  • Incorporate public input – Address recreational user, local resident, and native community preferences, as appropriate.
  • Use site-specific analyses – Conduct detailed environmental, engineering, and economic analyses tailored to the conditions and needs of each individual road.
  • Consider partial paving – Where appropriate, pave segments with higher use or erosion potential while leaving low-use portions gravel.
  • Re-evaluate over time – As conditions change, periodically reassess paving needs and priorities to reallocate investments wisely.


In summary, forestry trunk roads may be paved or unpaved depending on a variety of factors. Paving provides year-round access and accommodates more traffic but has higher upfront costs. Gravel roads are cheaper initially yet require frequent maintenance. The best choice depends on the specific conditions and needs of each road. Following sustainable road design and management practices allows forestry transportation networks to balance access, costs, and environmental protection.

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