Case study: Managing your Farm Forestry Trees - what's your Plan?
Note number: AG0813
Published: August 2003
This Agriculture Note is one in a series of case studies, and provides information on the factors involved when considering different management options for your trees.
Planting trees with the idea that one day they might provide some income is appealing to many of us. Whether the trees will grow to provide useful products and potential income will largely depend on the ongoing management and marketing of those trees. A recent field day on the Bellarine Peninsula looked at some of the management options which farm foresters should be considering when it comes to managing their trees.
The field day included a tour of a property with a four year old blue gum plantation of 6 ha. It was established along a degraded waterway to provide stock shelter. Another aimwas to improve the quality of the water flowing through the area into the dams. This water eventually ends up in the environmentally significant Swan Bay.
The trees have performed well to date, with the 4 year old trees approaching 9 m in height, and average stem diameters of 10-12 cm (approximately 30-40 m3 standing volume per hectare).
Management options to suit small woodlots
Figure 1. Rowan Reid from the University of Melbourne lead the discussion on the topic of which management options were suitable for the small woodlot.
The ‘do nothing’ option - just let the trees grow and see what happens
One option is to leave the trees alone, and grow them into an unmanaged woodlot which could provide some future options for firewood, pulpwood or posts. Either way, the trees would still be providing the key shelter and waterway protection benefits. With 600-650 mm annual rainfall, there is some concern with this option as to how well the blue gums will cope with drought stress as the trees become older and hungrier for moisture. It was suggested that some initial culling to reduce the stand density to <800 stems per hectare may hedge against the risk of drought deaths.
If growth rates of 8 t/ha/year continue, in 15 years there could be 720 t (6 ha x 120 t/ha) of firewood in the stand. If a woodcutter offered a stumpage of $5 or $10/t, then returns would be $3,600 and $7,200 respectively. If the woodlot was felled, dried and delivered to a local woodyard (receiving $50/t) the woodlot could gross$36,000 (need to subtract harvest and handling costs from this). Some Melbourne firewood sellers will pay up to $90/tonne. Blue gum is not considered as a high quality firewood.
Farmers aiming to sell pulpwood to exporters should consider meeting their key requirements of volume and quality. Because of the large volumes they trade in, farm grown pulpwood would need to be offered in lots approaching 10,000 t and have an absolute guaranteed quality (one piece of old wire in a farm grown log could do huge damage to their export program!). For this reason, farmers need to form local cooperatives which could ensure the volume and quality required to meet the buyers need. They would not be interested in dealing individually with growers of small woodlots.
With the above woodlot having some 720 t of material, the growers would need to combine their produce with othergrowers in order to arrange a deal for pulpwood. If this was possible and a stumpage of $25/t received then the woodlot could gross $18,000 (at age fifteen).
Managing the stand
If the trees are to be grown for the production of sawn timber products, then decisions on stand management need to be made early. At basal areas of over 10 m2/ha the diameter growth rate of eucalypt stands are retarded, increasing rotation length. If the aim is for this woodlot to grow into fat sawlogs as soon as possible, thinning of the stand would need to commence now (current basal area of 11 m2/ha). For more detailed information on pruning and thinning , refer to other Farm Forestry Notes in the Agriculture Note series.
When considering the sawlog option, the following points should be considered:
- rotation length - the time it will take to grow a 50 cm diameter sawlog will depend on the site quality and the thinning and pruning management of the stand (anywhere between 15 - 40 years).
- thinning - planting at high densities helps early growth, but trees must be thinned to allow the bettertrees to keep growing at fast rates. Start and continue thinning from years 3-4.
- manage for fast growth - growing trees at lower densities (100-400/ha) allows for much faster diameter growth. Clearwood pruning maintains high wood quality by controlling branch size and reducing knot defects. Thus a joint thinning and pruning regime willgreatly reduce rotation length while maintaining high quality logs.
- aim for large logs - for sawlog production, aim for larger diameter logs (>45 cm), as they have the advantages of higher milling recovery rates1, they are cheaper to harvest (less logs per cubic meter of timber) than skinny logs and mills find larger logs (and the sawn timber from them) easier to handle.
- final crop - if all cull trees were thinned to waste, and the final crop had 100 trees/ha, (50 cm diameter log to 6 m) then 100 m3 of sawlog per hectare would be available after about 25 years. Returns could varyconsiderably depending on how the 600 m3 of logs were disposed of.
- stumpage - if stumpage at $30/ m3 was received, the 600 m3 would gross around $18,000. If the stumpage was $80/m3 then the woodlot could gross $48,000.
- value adding - options for value adding could also be persued if the material was milled on site and sold green sawn at 50% recovery rate gives 300 m3 x $250/m3= $75,000 (this price could be increased if timber sold dried, but sawing and operating costs need to be considered).
The key points
As you can see there are plenty of different options to take, but like any farming enterprise, none come with completee guarantees. The key decision will need to take into account what best suits the situation of the landholder and property concerned.
Before entering into farm forestry, remember:
Planning - do all your homework, talk to lots of people and design the approach which satisfies your particular requirements (whether they be profitability, shelter, landcare, etc). Joining your local farm forestry network can help here.
Establishment - whichever venture you choose, make sure establishment is done right. Sites established poorly will never have prospects of being successful and profitable.
Management - do what you have to do to the trees to make sure they meet the requirements of the market. Don’t grow trees that no one will want to buy fromyou.
Marketing - make sure you know or understand all your marketing options for your trees (from the very beginning) including various lease options. Growing good trees is one thing, but those whose undertake the smartest marketing/sales options will be the ones who reap the rewards from their farm forestry venture.
Australian Forest Growers (AFG)
PO Box E18
Kingston ACT 2604
Ph. 02 6285 3833
DSE’s Private Forestry Web site:
Agroforestry News Request through Farm Forestry Network Contacts
Bird, P.R., Jowett, D.W., Kellas, J.D. and G.A.Kearney. (1996). Farm Forestry Clearwood Production: A manual for South East Australia.
Race, D. Ed. (1993) Agroforestry: Trees for productive farming. Agmedia, E. Melbourne.
Reid, R. and Stewart, A. (1994) Agroforestry - ProductiveTrees for shelter and Crop Protection in the Otways. The Otway Agroforestry Network, Birregurra Victoria.
Washusen, R. & Reid, R. (1996). Agroforestry and Farm Forestry: Productive Trees for Shelter and Land Protection in North East Victoria. Department of Natural Resources and Environment, Benalla.
See other Farm Forestry Notes in the Agriculture Notes series related to stand management (via the Private Forestry Web site).
This Information Note was developed by Graeme Anderson, Geelong
1 Higher recovery rates are achieved from larger logs due to the fact that logs are round and the timber cut is square. Small diameter logs have a greater percentage of timber wasted due to lots of edges ie. by the time the log is squared up there is not a lot of timber left to cut. Large diameter logs have a greater percentage of useable timber thus a higher milling recovery rate. Larger logs also have lower fixed costs per unit volume for transportation and milling ie. to fall, cut, load and deliver a log 50 cm dbh (1m3 wood) is cheaper than to fall, cut, load and deliver three 30 cm dbh logs (1m3). Larger logs will also have reduced growth stresses in the timber.