Be prepared for hard physical and capital investment to 'go it alone'

By Geoff North
Western Australia

The author, Geoff North, is a full-time farm forester managing 100ha of forest and 150ha plantation in south-west WA for high quality sawlog production. The main focus of his plantation silviculture is to produce the largest sawlogs in the shortest possible time frame. Geoff has been practising farm forestry for 20 years and is qualified in hardwood falling and shotfiring and has a BSc from UWA. He has developed the family farms from scratch with no full or part-time employees and only utilising contractors for pruning and some of the first and second thinning operations.

Between 1991-2011, he planted a range of species in blocks including E. saligna, E.botriodes, C. maculata, E. muelliania, E. globulus and several specialty indigenous WA eucalypts. Adjacent forests are recognised as providing ecosystem services to the plantation and benefit from a program that aims to control fuel levels and promote biodiversity, as well as provide wood production. Current annual production from the 300ha estate of logs is 1,000+ tonnes of logs and 10m3+ of sawn timber. This is forecast to increase to 2,000 tonnes and 100m3 in the next five years.

Commercial harvesting (as a result of the third thinning) of the plantations is delayed until 10-15 years to take advantage of the larger piece size and therefore lower-scale technology equipment requirement.

The main lesson I have learnt in regards to harvesting is that if you are focused on high intensity management (that is, frequent heavy thinning) to produce large logs quickly, you tend toward small scale plantation compartments where the trees have large branches in the crown as well as large boles. As a consequence of this, machine harvesting is not an attractive option given the economies of scale, the geometry of the crown and the risk of damage to either retained stems, or (in the case of clearfelling) pruned portions of the harvested trees.

This means that you have to be prepared for the hard physical work and capital investment to 'go it alone,' or you need to be larger scale and preferably close to residue log markets to make 'one hit' machine thinning work. Crucial to this is having access to skilled machine operators.

Harvesting process

Landings are positioned at either end of the rows.

The first step in the harvesting operation is to ensure adequate access for long vehicles to haul the product. This is actually achieved progessively over previous years as part of preparing the plantation compartments for summer wildfire.

The next task is to mark trees for retention (that is, the final crop trees) and demarcate the extraction lanes to forward the logs.

A Stihl MS 362 fitted with a 45cm bar is the primary machine for directional hand-falling. The trees are felled precisely so as to minimise damage to the final crop trees and spread the resulting slash evenly throughout the stand. Tops that land on the perimeter firebreak are immediately chipped by a PTO-driven brush-chipper and sprayed back into the plantation edges. This maintains optimum access and fire protection

Harvested trees usually average 35cm DBHOB and produce three logs 3.6-4.8m in length. The logs are then debarked with a dedicated log-grab mounted on a Komatsu PC-120 tracked excavator and presented in bunches of two or three in the lanes immediately adjacent to the extraction lane. Average log weight (bark off) is 250kg.

Logs are then forwarded to the nearest landing on a  Moheda 155-4WD log trailer towed by a JD 6630 92 kW tractor. The payload of 10-12 tonnes is delivered to the nearest landing to eventually be loaded on a truck and carted to the customer. Over 50% of butt-logs are suitable for milling into sawn timber, but sawmills (and the final consumer) in WA are not yet sophisticated enough to accept this product.

The following production rates have been observed in this type of operation in average to high quality stands:

• Manual harvesting: 2.5-4.5t/hr;
• De-barking, sorting and bunching: 10t/hr;
• Extraction: 20t/hr;
• Loading: 40t/hr;
• Total yield: 50-75t/ha.

Clearfell harvesting of final-crop, wide-spaced, pruned plantation is practiced using a hydraulic log-grab mounted on the tractor's three-point-linkage. It has a four ton lift-and-skid capacity.

Trees are felled using a Stihl MS 441 with a 45cm bar and an MS 660 with 50cm bar. Pruned sawlogs are cross-cut at the stump enabling tops (consisting of chiplogs) and sawlogs to be skidded to the landing and separated there.

The remaining stumps are ground using a PTO-driven stump-grinder leaving a clean site for re-establishment of the next crop.

As this type of harvest has only been conducted a few times no reliable figures for production have been assessed. Yields from 50-60cm DBHOB trees are likely to be 200-350t/ha with a 50/50 sawlog/chip-log mix.

I feel strongly that nowhere near enough support is being offered by all levels of government for small scale, high value farm forestry. In short, there needs to be increased privatisation of native forest logging (that is, more realistic economics in setting public forest returns to government), more scrutiny of wood product imports, and a differentiation so far as planning permits are concerned between farm forestry plantations and industrial-scale plantations for lower quality timber production. There’s something there for all three levels of government to consider.

Geoff North has been practising farm forestry for 20 years and is qualified in hardwood falling and shotfiring and has a BSc from UWA. He has developed the family farms from scratch with no full or part-time employees and only utilising contractors for pruning and some of the first and second thinning operations.