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Logs & Long-Lines

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'Fire-Sale' or 'Salvage' logging in the USA - whose proponents are as passionate about the subject as are its opponents - uses many methods to recover burnt tress and to reduce an area's fuel load. The use of helicopters to recover timber is the most expensive method but it has the least impact on the environment.

Fire prevention management of the United States' forests has changed over the past few decades. Much of that change has been forced on the United States Forest Service (USFS) by the courts in response to a vocal environmental lobby that has resulted in a significant reduction in off-season hazard-reduction burns which previously kept fuel loads lower and reduced the intensity and damage of seasonal summer fires. The results have been more intense and more damaging fires in recent years; in 2000, for example, over 92,000 wildfires burned 7.5 million acres of forest and grasslands - more than three times the ten-year average. Because of the increased severity of fires (resulting from fewer controlled burns) the USFS' aviation component has had to increase in size to counter the larger and fiercer outbreaks.

Salvage Logging

In an attempt to reduce fuel loads remaining in burnt areas, the USFS conducts salvage logging through what are known as post-fire sales. Although most of the trees lost to wildfire are extensively burned and charred, many retain some salvageable wood, the residual value of which depends on several factors including the species of trees, the extent of burning (how much moisture remains), the trees' accessibility and how difficult they are to recover; understandably, the more expensive its recovery, the less valuable is the wood. According to the Forest Service, salvage logging of burned areas helps to re-establish healthy, fire-resilient ecosystems. Intensively burned areas stripped of topsoil and ground cover are more vulnerable to erosion, and charred trees invite insect and disease attacks.

Just because a tree may hold some green after a fire, it does not guarantee its survival and assessing the likelihood of its survival is part the forest manager's job. Forest industry commentators believe that the pressure applied by environmental groups over the past 20 years has seen most USFS managers become overly cautious in selecting trees for logging. Whereas, during the 1970s, managers would cut trees whose likelihood of dying was only 30 percent, now, they are now reluctant to select trees with less than 60 to 70 percent likelihood of dying. Unfortunately, the more cautious approach has resulted in worsening beetle and fungal infestations. Insects attracted to burned trees bring decay fungi when they burrow into the wood and damaged trees are less able to recover from such infestations. Severely burned trees generally need to be harvested within two years, but trees in less badly burned areas may be left for up to four or five years.

Following a major fire, the USFS carefully examines every aspect of an affected area to assess its suitability for salvage logging. Flora, fauna, soil and water conditions are all considered in an assessment, which often runs to a 500-page report, in which managers also determine the most suitable method for logging a particular area. The assessment reports are subject to public review and consideration is given to input from public, environmentalist groups, and lumber companies before final decisions about logging are made. Opponents believe that post-fire salvage logging does more harm than good, and that the USFS uses the 'forest health' argument merely as a ruse to help the logging industry by providing its loggers with more timber; in some cases, environmentalist groups have successfully persuaded the courts to either stop or delay sales - as has happened in Six Rivers and Lassen National Forests, where the plan had been to cut around 70 million board feet (MBF) from 3,500 acres. Such delays can be expensive for the USFS because as wood continues to dry, it becomes increasingly un-useable; in some cases the delays have rendered the wood so worthless that the USFS has had to virtually beg loggers to remove it in order to reduce fuel loads and allow regeneration to proceed.

The view of proponents of salvage logging is that the system allows forests to recover more quickly - and in doing so, to recover to a more fire-resistant state. Additionally, salvage logging recovers some economic value from the dead trees and provides job opportunities and income to local and regional communities and offsets some of the costs associated with reforestation and fuel reduction treatment. Where salvage logging does take place, the USFS is careful to ensure that - while contractors are required to remove excess debris - enough material is left to feed the soil and reduce soil erosion.

Helicopter logging

Industry experts generally agree that salvage logging can reduce the severity of a future fire but at the same time, it can also damage the soil because roads are still needed in most cases to haul out the burned timber. According to some experts these roads can cause more harm than the actual salvage operation. In other words, the damage is not so much caused by the logging itself, but rather by the infrastructure needed to support it - and significantly, the 'less expensive' methods are the most likely to cause the greatest damage. Helicopter logging requires the least infrastructure and thereby causes the least damage (because of its minimal impact, helicopter logging has also been proposed in a number of instances to remove damaged or felled trees from hurricane-devastated forests) - but it is the most expensive.

In the case of wildfire salvage, those areas proposed for helicopter logging are usually severely burned with nearly all their trees killed. Usually, their inaccessibility and/or resource constraints have prevented these areas from having ever been logged before with the result that standing volumes and concentrations of large trees are generally high. Some contain up to 22 MBF per acre standing volume in trees greater than 12 inches diameter. Salvage from steep slopes (greater than 40%) usually makes helicopters the only practical method of logging their dead trees.

Helicopter logging is utilised most widely in the United States, where, in recent times, around 2.5 million cubic metres have been harvested annually. A Sikorsky S61 can produce on average, 350 cubic metres of logs in a six-flight-hour day, while a Vertol 107-II is capable of producing up to 1,000 cubic metres per day. As Columbia Helicopters' Dan Sweet points out, there are a number of variables affecting such figures, including the length of the day, weather, wood weight (which varies greatly by species, length of time since it was cut and the weather), and haul distance. "You can also include other variables such as crew experience, the size of the log landing, and the log handling equipment on the landing. Even maintenance practice comes into play."

The use of helicopters to harvest wood in other industrialised countries is rather restricted and mostly limited to emergency or special cases although in New Zealand HeliHarvest successfully uses the Mi-8, a helicopter with a rated lifting capacity of 11,020 pounds (5,000kg). Some helicopter logging operations have been introduced in developing countries including Papua New Guinea and a private US/Australian firm has successfully undertaken harvesting operations in Sarawak's natural forests for the past few years.

In the US, where heli-logging is proposed in a USFS area, its feasibility is analysed by first developing a 'paper' plan for the area. This plan is basically a map showing the proposed logging units, roads, and helicopter landing locations necessary for the logging. It includes an evaluation of aerial photographs and topographic maps of the area in conjunction with stand characteristics such as tree volume, diameter, and distribution information, and other pertinent data provided by Forest Service specialists. Parts of the plan are field-verified to confirm the accuracy of assumptions and to verify critical items such as landing area sizes.

Landing areas

Helicopter logging operations use two types of landing areas. Log landing sites are where helicopters deposit logs that are subsequently loaded onto trucks and service landing areas where helicopters are refuelled, maintained, and parked. Neither of these landing areas has a significant impact on the environment because they are so confined. Log landings are important to the economy of an operation. Their location and size, with respect to the trees to be logged, are important factors. They are usually located as close as possible to the areas to be logged to minimise helicopter yarding cycle times. The relationship between elevation and yarding distance - called the angle of ascent or descent - is also considered and should not exceed 30% although this is not a hard rule.

Yarding distances in excess of one mile are avoided if possible to reduce cycle times. Ideally, a landing is best located below an area being logged, however, a helicopter can usually yard uphill almost as efficiently as down - albeit with increased cycle times - so they are generally factors such as access, size, or construction cost that dictate where log landings are located. More than one helicopter can be yarded to a log landing area. Log landings need to be large enough to safely land, store, and load logs and generally require approximately one acre of relatively level ground (less than 6% slope) in size, though in some situations, smaller areas can suffice if fewer logs are landed. Landing areas must be clear of any loose debris and provide obstruction-free flight paths into and out of drop zones.

Service landings need to be accessible to fuel trucks and be constructed to safely store fuel and contain hazardous material in case of accident or spillage. They should be close to log landings but because of their greater construction cost, it is common to have one site servicing multiple log landings.

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