In Goobang Shire Objections Else-Mitchell J summarised the problems facing the valuer in determining the value of clearing:
Without being critical of the detailed investigations made by the parties, their legal advisers and valuers, I must say at once that these steps do not provide a very satisfactory means of determining the value added to land be clearing and timber treatment for the cost of such work must of necessity vary with the nature, volume, and density of the indigenous timber which was originally on the land and which would have to be taken off before it could be turned to agricultural pursuits. So much was made clear by the contractors who were called to give evidence by the appellants, and who stated that they expected a specified return for each hour of operation of their bulldozers, tractors, and other machines, and that the area which could be covered in a given time varied with the nature and density of the timber and. indeed, that in some instances they would
refuse to quote a firm price for the clearing of specified areas and would undertake that work only on the basis of an hourly or daily charge for a particular machine with driver or operator" - Objections to Valuation – Shire of Goobang, (1969) The Valuer January, 1970, p57 at p 59/60.
The cost of clearing is a function of:
Water content of the soil
Degree of clearing
The clearing program.
"Tight" country tends to increase the cost of clearing. Generally, basaltic soils are the most expensive to develop because of a deep "A" horizon and high fertility which promotes deep roots and large trees. Sedimentary soils vary with the soil type.
Soils with a shallow "A" horizon overlaying clay or slate will grow shallow rooted trees which are easily pushed out. Stony country with slate or shale rock breaks up easily around the tree's base allowing the roots to break out. Granite soils are the easiest of soils to develop. However, clay granite soils may be "tight" and the trees deep rooted.
Coarser granite, such as "bull" or "salt and pepper" granite, which has broken down to a sandy texture is the easiest country to clear even though the trees may be deep rooted.
Rocky basalt is easy as the "floaters" enable the soil to break up easily. On the other hand, granite tors are deep based and may protect the timber from the operator.
Damp soils make clearing easier particularly, in basaltic soils. However, in sedimentary country the operator may be hindered by the slippery nature of the soil and tends to "cut" the soil up with the bulldozer. On the other hand, granite soils provide a firm base for the operator even when wet.
The larger the timber, the more expensive it is to clear. However, large trees such as box apple and some stringybarks are better left as shade and shelter or as a future source of fencing timber. Regrowth and scrubby timber such as black sallee, honeysuckle and wattle are easily handled by a bulldozer with blade even when dense. However, twin or multiple suckers growing from an old root require special care as they tend to easily break off. In open country where there are stands of scattered regrowth the timber can be pulled down using two bulldozers and a rope or chain.
The cost to clear thinned timber is nearly as much as for virgin timber, especially when a large bulldozer is used. This is because the fixed costs, and time spent in pushing and stacking are about the same.
Stringybark is easily pushed out as it can be hit hard with the bulldozer without breaking. On the other hand, red gum is brittle and requires greater care. Stumps are hard to push out when green but when old and rotting are easily removed. Similarly, standing dead is easy to push over and burn. The timber type affects the ease of burning off.
Box, stringybark, blue and red gums are easy to burn but white gum is difficult. Apple does not flame but smoulders well. Peppermint does not dry out easily and tends to remain waterlogged.
Level to undulating country is the cheapest to clear as economical methods such as a rope or chain can be employed. However, level country often has the largest trees. Hilly country is expensive to develop with a bulldozer because of the extra time required to get in and over the country. Optimum development on such country is the poisoning of the trees with a "poison axe" and then Air Seed and Super (ASS).
The larger the area to be cleared, the lower the cost per hectare. This is because the fixed costs of the operator such as acquisition, depreciation, and transport of the machinery to the site is spread over a larger area. This applies particularly to very large bulldozers which can clear a large area quickly.
As the area of the development program increases, the crossover point is reached where the larger bulldozer becomes cheaper per hectare. The cost to clear a very small area is almost wholly; fixed costs.
DEGREE OF CLEARING
A problem with the use of air photos in assessing timber density is that the canopy cover does not accurately represent the density of timber on the ground.
A paddock with scattered shade and shelter may constitute about 50% of the paddock's area but the cost to clear is much less than one camp of timber which covers 50% of the paddock. This is because more efficient use is made of the equipment as the operator has plenty of room to manoeuvre. Further, cheaper methods such as the rope or chain can be used. Clearing virgin country can be "messy" resulting in higher costs in ploughing and cleaning up.
The major parts of the cost in clearing virgin country are variable costs.
COSTS ON COST PER HECTARE
After fixed costs, the costs of clearing in undeveloped country consists mainly of variable costs. The curve remains fairly flat findicating little difference for thinned country. The curve then sweeps and again, flattens out. This indicates that because of fixed costs, there is very little difference in the cost to clear for example, regrowth representing 80% tree cover and standing dead or "dirty" country about 95% developed.
The early stocking of newly cleared paddocks will help keep it clean and raise it's natural fertility. Further, early stocking helps the establishment of a prepared seed bed.
Most clearing is undertaken with a bulldozer equipped with a blade or shovel. However, 4 wheel drive tractors are popular as they have good torque and traction especially on level and undulating country and are more manoeuvrable and quicker than a bulldozer.
Some owners prefer the contractor to leave small jobs such as regrowth and the removal of debris to themselves as these are easily managed with a tractor. Other equipment commonly used are rural root rakes, tree pushers, and front end loaders which have a greater lifting force.
A blade and rake gives a clean job if the operator takes more time. Although initially more expensive, it is cheaper in the long run. On the other hand, the rope or chain is the cheapest for large areas even though it is more messy. Regrowth is controlled by:
Skilful management after development
Use of modern weedkillers, for example, Tordon
Use of a mulching implement which batters regrowth and debris into a mulch.
Use of the mallee scrub rake
Major savings in development costs can be achieved by:
Pushing timber over into windrows and allowing the operator time to do a clean job.
Plough immediately between windrows with a disc plough to level ground and break up debris.
Graze for one year, root rake to burn and stack into windrows. This will clean up any regrowth at the same time.
Clean subsequent regrowth with a mulcher.
An alternative program is as follows:
Graze new growth for 1-2 years
Push standing dead over and then stack and burn. Dead timber burns very easily.
Disc plough and control any subsequent regrowth with a mulcher.
Under both programs manual labour is kept to a minimum. Labour is also becoming harder to get particularly, for dirty jobs such as "grubbing", "sucker bashing" and burning off.
Windrows must be well made, compact and high to be economical. Green timber even when well stacked will result in gaps during burning. For less dense timber, heaps are more economical than windrows.
There are two ways of attacking the timber:
Push timber to thickest point moving around it
Make parallel runs through the timber and then windrowing at right angles.