High Surface Tillage

by John Bartlam

Moving large quantities of downed timber, or forest harvest residues into windrows or piles for burning, has always been an expensive and time-consuming exercise. Once land clearing was mechanised, this job was initially carried out by fitting a rake onto the front blade arms of a dozer, but this was still considered too slow for large areas and it was always problematic to try to rake across the tops of exposed residual tree stumps.

By the 1960’s a heavier version of a rotary hay rake was introduced, with spiked wheels that were able to ‘float’ over smaller stumps, but they were much too light for use on anything else but very light sticks, such as were found when clearing mallee and heath scrub country in S.A. and W.A.

For much heavier timber, such as brigalow scrubland in Queensland, it was not until the much heavier Symonds Rotary Rake was introduced in the late 1970’s, that a viable alternative was found to conventional front raking and even today, huge areas of raking are still carried out by very wide rakes on large wheeled and tracked dozers. For forestry work, with large amounts of slash to be raked across lines of harvested stumps, the problem of raking the site clean enough to replant new seedlings becomes almost impossible when you are only able to use a front-mounted stick rake.

Rear view of typical windrow being pushed up by a large Savannah six-wheel rotary rake. These machines are capable of working over the top of quite high stumps . Using a rotary rake behind a large wheel tractor, is far more efficient than using a front-mounted stick rake.

In 1987, Savannah introduced the first heavy forestry rake into the Australia, to the Queensland Forestry. It was a Model 1214 Rotary Rake that weighed over ten tonnes, was fitted with 35.5 x 32 logger tyres on the rear and had 2.4 metre raking wheels. It was a dramatic design development at the time and is still in constant use in the State pine forests around Maryborough, raking the huge amounts of logging debris at the landings into manageable piles.

We now have large areas of eucalypt plantations being developed across Australia. With a much shorter rotation length than pine, some of these plantations are already reaching maturity and harvesting has actually commenced in areas of Western Australia. The very large quantities of residues in these plantations, concerns about fire risks, the durability of the material and inability to access the soil with conventional tillage and replanting equipment, have all directed the attention of forest managers to ways of managing this new eucalypt harvest problem.

On inspection of the job being done in Queensland with the big forestry rake, contractors from both Australia and Argentina have seen what can be accomplished with a massive version of the ‘rotary rake’ and have placed orders for the latest model of stick rake from Savannah, the big Model 1226.

Model 1226 Rotary Stickrake with six, two-metre raking wheels and 13tonne operating weight, going to work with a 300hp Steiger tractor fitted with 35.5 x 32 logger tyres. Manjimup area, WA.

The last of these was recently delivered to contractor Peter Hartridge, of Woodyoke Pty Ltd, Scott River, WA. He is pulling it with a specially modified 300hp Case-Steiger tractor, fitted with big 35.5 x 32 logger tyres and a full forestry guarding package.