Underwater logging

Last updated

Underwater logging is the process of logging trees from underwater forests. When artificial reservoirs and dams are built, large areas of forest are often inundated; although the trees die, the wood is often preserved. The trees can then be felled using special underwater machinery and floated up to the surface. One such machine is the sawfish harvester. There is an ongoing debate to determine whether or not underwater logging is a sustainable practice and if it is more environmentally sustainable than traditional logging.

Contents

Underwater logging has been introduced in select locations around the world, including Ghana's Lake Volta, [1] the largest reservoir by surface area in the world.

A related form of logging consists of salvaging logs which loggers have abandoned after they became waterlogged and sank. This activity can be quite profitable, since the prime "targets" are decades-old trees of a size and species difficult or impossible to find in their natural habitat.

History

Rivers were a main method of transportation in the logging industry in the 19th and early 20th centuries in the United States. In the spring, logs were floated down waterways, especially those surrounding the Great Lakes and Maine, to transport them to mills downriver. Logs with a higher density than the density of water would sink. [2] Other logs would get caught in jams, sloughs, or floods, and become lodged in the riverbed. Such logs were often known as "sinkers" or "deadheads." Loggers attempted to reduce the number of logs which remained in the river in order to maximize profits, but some losses were inevitable. Logs with legible log marks were sometimes returned to their owners. [3]

Underwater logs are safe from many of the forces which cause decomposition, including fungi. Log salvage operations began in the early 20th century across the United States. John Cayford and Ronald Scott's book Underwater Logging describes the process and prospects for retrieving sunken wood from American waterways, known as salvage logging. [4]

Salvage logging differs from underwater logging. Salvage logging recovers full-sized logs that were lost during past logging expeditions. Underwater logging uses new technology to cut down drowned trees that have been lost due to rising water levels or artificial reservoirs. [5]

Logging methods

Remote controlled vehicle

One method of unearthing sunken trees is by sending a remote controlled vehicle, like a sawfish harvester, underwater to fell the trees. The vehicle is controlled by a cable that sends electricity and control inputs to the vessel which sends back a video feed for the operator. The operator sends inputs from a control panel on a barge. When a tree is found the Sawfish attaches and inflates a flotation device to it so that after the tree is cut it immediately rises to the surface for extraction from the water. [6]

Attaching buoys

Attaching buoys is one of the main processes by which underwater logs are salvaged from the bottom of lakes and rivers. First, a scuba-diver must locate the sunken logs in the water, searching from about three feet from the bottom of the lake or river. Then, a buoy is placed around the log about three feet from its back. From there, a boat uses a gaff hook to catch the buoys and pulls the log close enough to the boat where the crew is able to tie the logs close to the side of the boat. [4] This process repeats itself until the boat is filled to its capacity, after which the expedition is completed, and crew must return to base before harvesting any additional logs.

Floating logs

Log transportation method along rivers Logging.jpeg
Log transportation method along rivers

In the case of floating logs that have not been drowned but may have been separated from initial logging routes and stuck on the banks of rivers and lakes, a new process is utilized. Here, truck inner tubes are completely deflated so that a diver can slip them over the logs. After this occurs and once the tubes are securely in place, a hookah compressor and a low-pressure hose re-inflates them so that they form a tight grip around the floating logs. This process gives the logs more buoyancy and gives loggers easier access points to harvest them. As many tubes that are needed are used to float the logs. [4]

Environmental impacts

Marine pollution

Ships are polluting both in the marine environment and in the atmosphere, and although it is difficult to estimate the magnitude of the problem, there is no uncertainty that increased usage of such ships will increase pollution. As the underwater logging industry becomes more popular and profitable, this increased usage will occur. [5] The process of underwater logging itself will also have a negative impact on the environment, as the logs themselves add weight to the ships, forcing said ships to work harder and use more time and energy to transport their cargo. [5] In terms of transportation, cargo ships transport the logs across the water. They use an immense amount of ballast water, which can have negative effects on the environment. When the ships reach the mills they empty the water, "Ballast water discharge typically contains a variety of biological materials, including plants, animals, viruses, and bacteria". Dumping the ballast can change the aquatic ecosystems and even make the water undrinkable.

Accidents

Accidents related to this industry usually result in the release of oil and other resources, as these spills are difficult to maintain due to the fluidity of lakes and rivers. What this means is that the potential for collateral damage is large, both for marine and human life, because toxic resources such as oil can contaminate surrounding ecosystems. [5] It is necessary, therefore, to exercise caution when partaking in processes, such as underwater logging, that require the use of potentially harmful resources.

Deforestation

Because the underwater logging process is essentially retrieving drowned logs and sunken trees that were already lost in previous logging expeditions, the logs are considered "rediscovered wood." [7] Because underwater logging is retrieving "rediscovered wood," this has a positive impact on the forestry industry, as it reduces the need to log in land forests. In addition, when logging on land logging companies have to create new roads to get to higher quality wood. Road building is eliminated with underwater logging because the transportation paths across the rivers already exist. [7]

Potential erosion of lakes and rivers

Effects of erosion along Lake Erie Lake Erie erosion -- USGS.gif
Effects of erosion along Lake Erie

As some of these logs have been lost for upwards of a few decades, the local environment has inevitably grown and developed around said logs. Removing these logs, which provide structural support to a variety of these ecosystems, could result in erosion of the lakes and rivers that would change the structure and potentially degrade these bodies of water. [7]

Marine life

Some of the logs that are retrieved have been underwater for upwards of a few decades, meaning local marine life will have formed their habitats around these drowned logs. These logs provide substantial structural support for these ecosystems, and removing them would inevitably destroy said natural habitats. [7] Boats and crew members of underwater logging fleets can stir up and degrade the local ecosystems.

Sustainability

Nature & Faune magazine describes the process of underwater logging's sustainability impact. The hydroelectric dam in Ghana built in Akosombo submerges forests of timber logs. [8] The Clark Sustainable Resource Developments uses SHARC ROV technology to keep the roots of the trees intact not to disturb the lake bottom or disturb pollutants. After, they put canopies and buttresses to create artificial fish reefs and educated locals about fishing practices. Lastly, they can cut up to 25 meters (82 ft) below the lakes surface, which creates a depth sufficient to support routes for transportation lake vessels. This process was awarded for being sustainable by avoiding deforestation and making artificial reefs to maintain the current aquatic ecosystem. [8]

Related Research Articles

<span class="mw-page-title-main">Maritime archaeology</span> Archaeological study of human interaction with the sea

Maritime archaeology is a discipline within archaeology as a whole that specifically studies human interaction with the sea, lakes and rivers through the study of associated physical remains, be they vessels, shore-side facilities, port-related structures, cargoes, human remains and submerged landscapes. A specialty within maritime archaeology is nautical archaeology, which studies ship construction and use.

<span class="mw-page-title-main">Logging</span> Process of cutting, processing, and moving trees

Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. In forestry, the term logging is sometimes used narrowly to describe the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard. In common usage, however, the term may cover a range of forestry or silviculture activities.

<span class="mw-page-title-main">Buoy</span> Floating structure or device

A buoy is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.

<span class="mw-page-title-main">Shipwreck</span> Physical remains of a beached or sunk ship

A shipwreck is the wreckage of a ship that is located either beached on land or sunken to the bottom of a body of water. Shipwrecking may be intentional or unintentional. There were approximately three million shipwrecks worldwide as of January 1999, according to Angela Croome, a science writer and author who specialized in the history of underwater archaeology.

An underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature, such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation.

<span class="mw-page-title-main">Surface marker buoy</span> Buoy towed by a scuba diver to indicate the divers position

A surface marker buoy, SMB, dive float or simply a blob is a buoy used by scuba divers, at the end of a line from the diver, intended to indicate the diver's position to people at the surface while the diver is underwater. Two kinds are used; one (SMB) is towed for the whole dive, and indicates the position of the dive group throughout the dive, and the other, a delayed surface marker buoy, DSMB or decompression buoy, is deployed towards the end of the dive as a signal to the surface that the divers have started to ascend, and where they are going to surface. Both types can also function as a depth reference for controlling speed of ascent and accurately maintaining depth at decompression stops. Surface marker buoys are also used by freedivers in open water, to indicate the approximate position of the diver when submerged. They may also be used to support a catch bag or fish stringer by underwater hunters and collectors. A DSMB is considered by recreational scuba divers and service providers to be a highly important item of safety equipment, yet its use is not part of the entry level recreational diver training for all training agencies, and there are significant hazards associated with incompetent use.

<span class="mw-page-title-main">Diving shot</span> Substantial weighted near-vertical line with buoy

A diving shot line, shot line, or diving shot, a type of downline or descending line, is an item of diving equipment consisting of a ballast weight, a line and a buoy. The weight is dropped on the dive site. The line connects the weight and the buoy and is used by divers to as a visual and tactile reference to move between the surface and the dive site more safely and more easily, and as a controlled position for in-water staged decompression stops. It may also be used to physically control rate of descent and ascent, particularly by surface-supplied divers.

<span class="mw-page-title-main">Cofferdam</span> Barrier allowing liquid to be pumped out of an enclosed area

A cofferdam is an enclosure built within a body of water to allow the enclosed area to be pumped out or drained. This pumping creates a dry working environment so that the work can be carried out safely. Cofferdams are commonly used for construction or repair of permanent dams, oil platforms, bridge piers, etc., built within water.

<span class="mw-page-title-main">Marine salvage</span> Recovering a ship or cargo after a maritime casualty

Marine salvage is the process of recovering a ship and its cargo after a shipwreck or other maritime casualty. Salvage may encompass towing, lifting a vessel, or effecting repairs to a ship. Protecting the coastal environment from oil spillages or other contaminants from a modern ship can also be a motivator, as oil, cargo, and other pollutants can easily leak from a wreck.

San Pedro Underwater Archaeological Preserve State Park is a Florida State Park located in 18 feet (5.5 m) of water, approximately 1.25 nautical miles (2.32 km) south of Indian Key. It became the second Florida Underwater Archaeological Preserve when it opened to the public in 1989. The heart of the park is the San Pedro, a submerged shipwreck from a 1733 Spanish flotilla, around which visitors can dive and snorkel. The San Pedro, a 287-ton Dutch-built vessel, and 21 other Spanish ships under the command of Rodrigo de Torres left Havana, Cuba, on Friday, July 13, 1733, bound for Spain. The San Pedro carried a cargo of 16,000 silver Mexican pesos and crates of Chinese porcelain. A hurricane struck the fleet, while entering the Straits of Florida, and sank or swamped most of the fleet. The wrecksite includes an "eighteenth century anchor, replica cannons, ballast stones encrusted with coral, a dedication plaque, and a mooring buoy system." The wreck was added to the U.S. National Register of Historic Places on May 31, 2001.

<span class="mw-page-title-main">Neys Provincial Park</span> Provincial park in Ontario, Canada

Neys Provincial Park is a natural environment-class provincial park on the north shore of Lake Superior, just west of Marathon, Ontario, Canada. This 5,383-hectare (13,300-acre) park includes the historic Coldwell Peninsula and the surrounding island system, consisting of Pic Island, Detention Island, and the Sullivan Islands.

<span class="mw-page-title-main">Disposable ship</span> Ship or sea vessel intended for use on a single voyage

A disposable ship, also called raft ship, timber ship, or timber drogher is a ship or sea vessel that is intended for use on a single voyage. At the final destination, the vessel is broken up for sale or reuse of materials. Until the end of the 19th century, such ships were common on major rivers such as the Danube and the Rhine in Central Europe and the Mississippi in North America. There were also saltwater vessels that were primarily built for one-time sailing to break up. Some of the largest wooden ships in history were of this type.

The following outline is provided as an overview of and guide to forestry:

<i>Ax Men</i> TV show about loggers

Ax Men is an American reality television series that premiered on March 9, 2008 on History. The program follows the work of several logging crews in the second-growth forests of Northwestern Oregon, Washington and Montana and the rivers of Louisiana and Florida. The show highlights the dangers encountered by the loggers. Following in the footsteps of other shows from Original Productions, like Deadliest Catch and Ice Road Truckers, the series is considered part of a recent "real-men-in-real-danger" television programming trend.

The following outline is provided as an overview of and topical guide to fishing:

<span class="mw-page-title-main">Log jam</span> Accumulation of large wood in a stream or river, preventing movement downstream

A log jam is a naturally occurring phenomenon characterized by a dense accumulation of tree trunks and pieces of large wood across a vast section of a river, stream, or lake. Log jams in rivers and streams often span the entirety of the water's surface from bank to bank. Log jams form when trees floating in the water become entangled with other trees floating in the water or become snagged on rocks, large woody debris, or other objects anchored underwater. They can build up slowly over months or years, or they can happen instantaneously when large numbers of trees are swept into the water after natural disasters. A notable example caused by a natural disaster is the log jam that occurred in Spirit Lake following a landslide triggered by the eruption of Mount St. Helens. Until they are dismantled by natural causes or humans, log jams can grow quickly, as more wood arriving from upstream becomes entangled in the mass. Log jams can persist for many decades, as is the case with the log jam in Spirit Lake.

<span class="mw-page-title-main">Float (nautical)</span> Flotation device

Floats are airtight hollow structures, similar to pressure vessels, designed to provide buoyancy in water. Their principal applications are in watercraft hulls, aircraft floats, floating pier, pontoon rhinos, pontoon causeways, and marine engineering applications such as salvage.

Harbor Clearance Unit One, a United States Navy unit, was commissioned in February 1966 with the mission "....to provide salvage repair; diving and rescue services in rivers and restricted waters and to conduct harbor and river clearance operations in the Western Pacific." Some contended that the intended mission was to provide rapidly deployable diving and salvage teams in direct support of the Vietnam War. Whatever the actual intent was, the concept was proven so effective that the command was moved to continuous salvage service at Pearl Harbor, Hawaii, near the end of the Vietnam War.

The Lake Washington sunken forests were both a part of the scientific discovery of a major fault line under Seattle, Washington, and part of a timber piracy case in the late 20th century. In a precedent-setting case, the Washington State Supreme Court decided that ancient drowned forests are state property and not eligible for salvage.

Ocean development refers to the establishing of human activities at sea and use of the ocean, as well as its governance.

References

  1. Randalls, Samuel; Petrokofsky, Gillian (2014). "Saws, Sonar, and Submersibles: Expectations of/for Underwater Logging" (PDF). Geoforum (214): 16–20 via UCL Discovery.
  2. Schreiner, Rodney (9 September 2016), "Blue Sky Science: Why do some logs float and some sink?", YouTube, Madison.com.
  3. Bachmann, Elizabeth M (June 1945). "Minnesota Log Marks" (PDF). Minnesota History. 26 (2): 127 via JSTOR.
  4. 1 2 3 John E. Cayford and Ronald E. Scott. Underwater Logging. Cambridge, MD: Cornell Maritime Press, 1964.
  5. 1 2 3 4 Kristiansen, Svein. Maritime Transportation: Safety Management and Risk Analysis. N.p.: Routledge, 2004. 1-46. Web. 20 Mar. 2015
  6. Tenenbaum, David (2004). "Underwater Logging: Submarine Rediscovers Lost Wood". Environ Health Perspect. 112 (15): A892-5. doi:10.1289/ehp.112-a892. PMC   1247634 . PMID   15531424.
  7. 1 2 3 4 Tenenbaum, David J. "Underwater Logging: Submarine Rediscovers Lost Wood." Environmental Health Perspectives 112.15 (2004). Web. 20 Mar. 2015
  8. 1 2 Asare, Godfred, and Sean Helmus. "Underwater Logging: Ghana's Experience with the Volta Lake Project." Nature & Faune 27 (2012): 64-66. Print.