Opinion

Helicopter Logging - the way forward is up

 Dr Garth Cambray

For most people the concept of logging conjures up images of huge swathes of beautiful forests razed to the ground to make chipboard and pallets for our relentless commercial expansion. Obviously, this is environmentally unsound and unsustainable - a better way has to be found so that forests can be managed to produce valuable products that in a way pay humans to look after and protect the forests from environmentally worse options, such as ending up under a strip mall, or sugar cane plantation.

Conventional logging operations employ bulldozers to make roads into the forest, after which trees are felled and some sort of tractor or animal pulls the logs to a central area where they are loaded on trucks and taken to a mill. It is not uncommon to drag a bundle of large logs up to a kilometre through the forest to reach a loading area - the logs drag behind the tractor and flatten much of what was left of the forest contributing to erosion and loss of biodiversity.

If one looks at the mathematics of a tree, it is essentially a cylinder, which as it grows increases its volume. This rate of volume increase is very slow when the tree is young and has a small diameter, but as the tree gets larger, a few years growth can increase the volume of timber in a fast growing tree by as much as 15%. Hence if a government is selling timber by volume, and deriving revenues, clear felling represents a huge loss of income as a forest may have a lot of small trees in it that would in 10 years time have yielded twice the volume of timber. The answer is to use selective non-disruptive logging methods to take mature trees out of the forest just before they die and let the smaller trees around them fill in the gaps and produce timber again quite soon.

Mil Mi26t seen flying over a typical savannah landscape carrying 20 tons of logs harvested from an African rainforest.

To do this, the only way out is up, and the only things which can go up and down in many places in a forest are helicopters, airships and balloons. Balloon logging has proven a bit complicated, but helicopter logging is highly successful and practised in many parts of the world, including Africa. (As far as airships go the Hindenberg still has a lot to answer for.)

Many different helicopters can be used for the task of logging, ranging from the heavy lift Mil Mi 26 (20t) and Sikorsky S-64 Skycrane (11t), to medium power helicopters such as the Boeing Vertol 107-II and smaller Mil 8 (5t) and KAMOV Ka-32 (5t).

Generally a light helicopter is needed to take felling teams into the forest together with forest management personnel a few weeks prior to the heavy lift helicopter arriving. Appropriate trees are selected and felled and all the small branches are cut from the sides of the trees. The coordinates of each log are recorded with a high accuracy GPS unit so that logs are not lost in the forest. Logs are also typically painted with bright paint to aid aerial identification.

The volumes of logs are calculated to provide a rough idea of the weight of each log. This is important, as with a helicopter like the Mil Mi 26, the helicopter can lift close to 5 tons more when it has an almost empty fuel tank. If the logging logistics are carefully calculated, a minimum number of flights can be made to remove a maximum load of logs, thus further reducing environmental impact in terms of fossil fuel wasted and that increases profits.

When logging with the Mil Mi 26, logging teams typically place cables around the logs and the helicopter team comprising two pilots a flight engineer and a cable operator, quickly hook the cables and lift as many as five logs into the air. With the Sikorsky S-64 operated by Erickson Skycrane, a patented grapple allows the helicopter to operate without a ground team and just scoop logs up - the disadvantage here is that it is more difficult to take multiple loads of big logs, but then this machine can lift a lot less than the Mil Mi 26 so this is not necessarily a problem. The advantage of the grapple is that with the fearsome wind blowing down from the giant helicopters rotors, branches and small logs can drift around and cause considerable damage to ground crews, so using a grapple makes it safer for people.

The loading zone - a large open area equipped with powerful loading cranes and equipment.

The logs are then taken to a landing zone where they are placed and loaded onto trucks. This is apparently according to the literature a dangerous section of the operation - which is probably why when I recently watched a helicopter logging operation moving logs a herd of cows grazed in between the landing logs and one guy slept under a heap of huge logs that looked like they had been thrown there by a giant playing pick up sticks.

It is estimated that a well run helicopter logging operation using a Sikorsky-S64 operated by Erickson Skycrane can lift as much as 20 000m³ of timber per month. The smaller Mil 8 can lift as much as 6 000m³ per month.

Studies conducted in mountainous regions of Sarawak showed that helicopter logging resulted in a huge decrease in turbidity in streams after logging, compared to tractor based extraction - ie there was a lot less erosion. Tractors caused as much as a 10 fold increase in erosion. In addition, for every tree extracted with a helicopter, between 1.45 and 3.13 were damaged compared to 5.49 for tractor extraction.

There are however drawbacks to helicopter logging. It is very expensive and requires highly skilled people to fly and maintain the machines. It is dangerous - in Alaska heli-logging is considered one of the most dangerous occupations.

There are also environmental objections to helicopter logging. It allows exploitation of resources that are so far from road and so inaccessible that normal logging has ignored them. This is in a way sad as it does allow us to get our capitalistic paws on even some of the most distant forests on Earth.

A case in point has recently been the decision by the US government to 'thin' forests so as to limit future fires. This may be good environmental management, as we all agree that to have more carbon freed up by the trees (and houses) that burn will obviously contribute to global warming. Or it may, in certain cases be extractive capitalism masquerading as environmental management. 

But whichever side of the environmental protection fence you sit on, the chances are you do use toilet paper, wooden products and printing paper. These require, in order for their continued availability to be ensured, that we manage our forests properly and in this light, helicopter logging has a lot to offer Africa, where clear cut forestry is robbing us of long term timber security by resulting in total destruction of the forest ecosystem.

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