Heli-logging, or helicopter logging, is a method of logging that uses
helicopter
A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...
s to remove cut
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...
s from
forest
A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...
s by lifting them on cables attached to a helicopter. Helicopter
logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksForest Service, the first opening of timber for sale cut exclusively helicopter logging in April of 1971 on the Plumas National Forest in California.
Helicopter logging in the United States started in late 1971. Jack Erickson, of Erickson Air-Crane, along with Wes Lematta of Columbia Helicopters, started heli-logging Northern California in the Plumas National Forest near Taylorsville, California.
Process
Heli-logging is also known as standing stem harvesting, which is based on individual tree selection (ITS). The selection process is done by
engineers
Engineers, as practitioners of engineering, are professionals who invent, design, build, maintain and test machines, complex systems, structures, gadgets and materials. They aim to fulfill functional objectives and requirements while consider ...
and surveyors. The trees are selected based on demand for specific types and grades. Before the selection process is complete, the selected trees are bored to check their reliability. The selected trees are then marked and their diameters are recorded. The diameter of the tree is measured at above the ground. The sizes of the trees that are selected are controlled by two things. The minimum size is controlled by the economy, while the maximum size is controlled by the capacity of the helicopter. Once the trees are selected they are climbed, the limbs are removed and the trees are topped. The length of the tree and the diameter at its top are then recorded. All the recorded data is then entered into a
database
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...
which calculates
volumes
Volume is a measure of regions in three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). The ...
, weights, etc. The selected trees are then partially cut at the stem and supported by wooden wedges. The stem is then grappled by the helicopter and pulled until the wood breaks at the partial cut. The logged trees are then brought by helicopter to a predetermined roadside location or dropped into open water where they are collected. Some trees are felled before being de-limbed, and then picked up by the helicopter.
Advantages
Heli-logging is efficient: a single
S-64 Skycrane
The Sikorsky S-64 Skycrane is an American twin-engine heavy-lift helicopter. It is the civilian version of the United States Army's CH-54 Tarhe. It is currently produced as the S-64 Aircrane by Erickson Inc.
Development Under Sikorsky ...
can extract of clean, undamaged timber per month. Conventional logging allows the stems to fall. On rocky terrains, this often results in damage to the stems that makes them unusable. On steep terrains, falling trees can slide downhill and become irretrievable. Heli-logging allows logging to take place in more remote places. It also allows certain trees to be logged that previously could not be due to their proximity to a structure or pipeline. Logging using helicopters is safer than conventional logging. Falling trees are dangerous for the loggers as well as for surrounding structures or
utilities
A public utility company (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and r ...
.
Helicopter logging ground crews will cut, clean, and mark the trees before the helicopter starts to work. Ground crews may be able to prepare fewer than six trees per day, and the helicopter will only be needed every few days. Since fewer roads need to be built to the site where the logging is taking place, and trees are extracted vertically, there is reduced damage to the surrounding trees and ground surface.
Research by Roberts, Ward and Rollerson done in 2004 shows that post-logging
landslides
Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslide ...
are more common after conventional cable-based logging than heli-logging. Landslide rates following conventional logging are one and a half times more common than landslide rates following heli-logging.
Disadvantages
Although there is no direct cost from road construction or expansion, heli-logging incurs high costs. Operation of a helicopter as well as the selection processes and methods increase the cost. The use of a helicopter to transport the stems limits the size and weight of the selected trees more than equipment would using conventional logging.