Timberlands Low Impact Aerial Harvesting
HISTORY OF AERIAL HARVESTING
Aerial harvesting was first trialed in Scotland in 1956. Numerous further trials were conducted during the late 1950s and 60s in Russia, North America and Scandinavia. By 1972 the use of helicopters had become an accepted practice in a number of countries. In New Zealand, helicopter harvesting trials since the late 1970s have included extraction of kauri and rimu pole thinnings, sawn timber and logs, as well as Pinus radiata thinnings and posts. On the West Coast, the recognition that sustainable rimu management would require low impact harvesting methods, resulted in trials commencing in 1978. However, commercial operations remained constrained, undermined by the log prices of the day. To implement sustainable management in rimu forests and remove the impacts of conventional operations, Timberlands West Coast Limited introduced this technique on a large commercial scale for the first time in New Zealand in 1993. Expressions of interest were received from 40 companies in six different countries.
Harvesting logs by helicopter follows a defined and strict operational structure. Timberlands West Coast Limited runs a “cold deck” operation where every stage is completed before the next stage starts. Ground crews fell and prepare logs to exact weights. A remotely actuated grapple on the helicopter longline grasps the logs which are then lifted and delivered to the landing site. Before being released logs are loaded out and transported to mills.
the nature of the operation limits the environmental impact of harvesting on the surrounding forest
the helicopter enables “true” selective harvesting where only those trees suitable for extraction are taken
the elimination of any cable or ground based systems ensures minimum damage to soil and water values and remaining forest
a substantial reduction in roading reduces one of the major potential causes of soil erosion
by lifting logs to the landing site there is not concentration of damage around the area
the scenic views of the forest are maintained
environmental risk under the Resource Management Act is reduced
the helicopter is the only extraction technique currently suitable for some sensitive forest types.
logs arrive at mill relatively free from stones, mud and other contamination
ease of transfer between locations increases operational flexibility
operation is not greatly influenced by volume per hectare or block
distribution roading requirements are significantly reduced
minimum lead in time is required for unexpected supply demands, i.e. “Just in time” inventory capability ability to operate in most weather conditions
economic if machine is tailored to scale of operation
Civil Aviation Requirements (CAA): All helicopter harvesting operations require a New Zealand Aerial Work Certificate and maintenance to high standards of airworthiness. Foreign helicopters are subject to tighter controls of registration, airworthiness and operational surveillance. The CAA require: copies of maintenance arrangements and programmes, validation of pilot’s licences, Certificate of Airworthiness, contact within the CAA in country of registration, that pilots have experience in New Zealand operating conditions. Strict, comprehensive policies and codes of practice must also be developed for ground operations. These apply to every person, from bushman to pilot. The use of a “cold deck” system also limits the number of people on site, thereby reducing risk.