Sustainable Timber Harvesting Using Airships
The forest industry is a cornerstone of the Canadian economy. In 2019, the forest sector employed over 200,000 workers and contributed about $23.7 billion to the nominal gross domestic product. The rich softwood forests of the Pacific coastal mountain region, which are about 23% of the Canadian forests, provide 40% of the jobs. The other 60% of the employment is in the boreal forest. This vast tract of forest covers 35% of Canada’s land mass.
In such a large country as Canada, forestry operations incur significant transport costs to haul their timber from the cutting sites to sawmills and processing plants. The value of timber depends on the log size, tree species and growing location. Large logs are directed to sawmills to produce lumber, while smaller trees are processed into plywood, kraft paper and newsprint. The forestry industry has had a longstanding interest in the use of airships to access its timber resources.
Harvesting in the Rocky Mountains
The mountainous terrain of Canada’s west coast contains the most valuable tree species, and also has the greatest logistical challenges. Logging roads often have to traverse hazardous, steep terrain and are expensive to build, maintain and decommission. Over the decades, helicopters, cable-logging and cable-balloon logging operations have been used or tested to harvest otherwise inaccessible areas of terrain. In all cases, they are expensive and often dangerous.
High elevations and tricky wind patterns make forestry operations in the mountains difficult. A number of experimental airships have been proposed for logging. A helicopter-airship hybrid known as the AeroLift CycloCrane was designed specifically for low-speed flight maneuvering to pick up logs. This airship used helicopter derived airfoil control, while spinning on its axis. Two Cyclocranes were flown in 1984 and 1985, but they did not get past the proof-of-concept stage before funding from the Canadian forestry companies ended.
The US Forest Service supported the development of the Piasecki PA-97 Helistat prototype for logging operations. The Helistat design involved combining elements of helicopter propulsion with a blimp envelope, to pick up logs. A fatal accident occurred during initial testing in July 1986, and the project was abandoned. A similar concept called SkyHook was initiated by Peter Jess in 2008, who had a contractual arrangement with Boeing. The SkyHook project was halted in 2010 when additional funding could not be obtained.
A Canadian project with a similar objective was undertaken by Magnus Aerospace. As illustrated in their conceptual drawing, Magnus was targeting the LTA 20-1 for the forestry market. This project did not get past the proof-of-concept stage, and Mangus ceased operations around 1986.
Currently, FLYING WHALES is developing a rigid airship for the express purpose of transporting logs out of the mountainous forests of the Alps, Corsica, and French Guiana. This airship is being designed to transport up to 60 metric tons through hard-to-reach places at altitudes of close to 3,000 meters. FLYING WHALES received its initial funding from the Office National des Forêts (ONF—French National Forestry Office), and has received further investment from the Government of China and the Province of Quebec. This strong financial base provides hope that a successful logging airship will emerge for use in mountainous areas in many forested parts of the world.
Harvesting on the Canadian Shield
The flat terrain of the Canadian Shield is less challenging than mountainous areas, but the tree species of boreal forest are not as lucrative. The tenacious vegetation is adapted to the local climate such that the trees tend to be small in stature, gnarly and in close proximity to one another. These characteristics favour processing applications and the milling of construction-grade boards, rather than finished lumber.
Forestry companies on the Canadian Shield face major transportation challenges to economic harvest of the boreal forest. First is the cost and regulations involved in accessing forest blocks. The boreal forest ecosystem is complex; made up of muskeg, swamps, rock outcrops and many water crossings. Logging roads are subject to an exacting environmental approval and conditions that can add significant costs to construction. Construction costs easily exceed $100,000 per kilometer to connect a harvest block to a staging area at an all-weather road. Here logs are transshipped to tractor-trailer highway trucks for transport to a processing plant.
A second challenge involves the transport of the harvested wood from the bush. Frozen ground and lakes provide a surface over which trucks can reach forestry camps to bring in supplies and transport out felled timber. Generally, logs are cut and left at a loading site until the roads are deemed safe to use. Longer water crossings are limited to winter ice road periods.
Ice roads cost about $5,000 per kilometer to construct and need to be rebuilt every year. Thirty years ago, the winter road season was about 55 days, but over the past decades it has often been much shorter (only 20 days in 1999/2000). The unreliability of the length of the winter road season reinforces the need to develop alternative methods of bringing the wood products effectively to market.
In addition to the obstacles of lakes and major waterways, direct routes to logging sites are often blocked by protected areas, parks or areas whose ownership is under dispute. These areas often require extensive negotiations and environmental assessments in order for forestry companies to gain access. Logging roads require regular maintenance and eventually, expensive decommissioning, to reduce potential liability from injuries received by public users wishing to gain access to the backcountry.
Airships could provide an alternative to the exclusive use of diesel trucks over logging roads, but to be competitive, the airship must be cost effective. The idea of using an autonomous logging airship for the boreal forest was first set forth by Juergen Bock and Uwe Apel (2010).1 A remotely piloted airship would have no human risk when flying over forested areas. There are significant benefits to using hydrogen as a source of both lift and propulsion. An airship filled with hydrogen can lift 8% more than helium and reduce total cost. Hydrogen-electric power for forward movement would have no greenhouse gas (GHG) emissions.
A logging company using remotely-piloted airships could avoid the cost of building access roads to their timber operations. As illustrated below, the transport concept envisions a number of small remotely-piloted airships that would be cycling between the cutting area, or outpost camp, and the transshipment depot where the trucks would be loaded for transport to the processing plant. Canadian air regulations already permit such non-line-of-sight operations for autonomous drones, under a special flight certificate system 2.
To be effective for forestry operations, a remotely-piloted airship would need to be about 35 metres in diameter. This would provide about 10 MT of useful lift and another 6.5 MT of additional lift to offset the weight of the airship structure, engines, propellers and fuel. The proposed airship would use hydrogen gas for both fuel and for lift. In contrast to the current carbon emission from diesel trucks, these airships would have zero-carbon emissions.
A conceptual diagram of the remotely-piloted airship is presented below. In this version, two auxiliary power units (APUs) are envisioned that would power generators to drive the electric fans. Alternatively, hydrogen gas could be used to obtain electricity via a hydrogen fuel cell. The airship would carry 10 MT of water ballast that would be exchanged for the weight of the logs being lifted. All the weight is held at the bottom of the airship and supported on the envelope.
The remotely-piloted airship proposal is not without challenges. The airship would need to drop water ballast when it picks up the cut logs, maintain balance in flight, and then unload the logs at the landing point, while picking up more water ballast. This would require the design of an effective ground-handling system. But above all, the airship must be relatively inexpensive to build and operate safely.
Globally, the forest industry needs to develop more sustainable practices. Airships offer a new technology to access and harvest natural wood resources in remote areas that are inherently more sustainable than current methods. Challenges vary with the geography and the value of the timber.
Progress is underway to develop an airship that can lift out large quantities of logs from mountainous regions (FLYING WHALES). For the boreal forests of Canada and Russia, remotely-piloted airships may have good potential as an innovative, cost-effective solution to address a number of the logistical challenges of the forest industry.
1. Bock, J.K. and U. Apel. (2010) “Concept of an Unmanned Automated Lighter-Than-Air Cargo Transportation
System for Northern Canada”. DGLR (German Aerospace Association).