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Production Thinning Offers Best Way to Ensure Production of High-Value Sawlogs at Final Harvest

 PF Olsen worked with Luke and his finance company to trade that machine for a Waratah head. This machine's base has no "tail swing" so is ideal for the confined conditions experienced when production thinning. It is a lot more flexible than a feller/buncher which is important in woodlot harvesting. The base is also self-levelling giving it the capability to work comfortably on steeper slopes.

This machine was not purchased specifically for production thinning but when the opportunity arose the crew took up the challenge. Their first assignment was a stand in Selwyn Plantation Board's Chaney's Forest. The stand had missed the ideal time to undertake a thin-to-waste operation and consequently the cost had increased to $460 per hectare according to forest manager Tim Hinton. In contrast, the production thinning project is currently returning a small profit to the forest owner.

The photo below shows the log grades being produced, predominantly posts and industrial grade sawlogs.

It is important that management of production thinning is driven from a silvicultural perspective (enhancing tree crop value) rather than a harvesting perspective (maximising returns from harvesting). If managed poorly, damage to the remaining crop can vastly outweigh any cost savings. This is where the right machine with a skilled operator is invaluable. In this project out-rows are being used for log extraction. The selected cull trees are felled, delimbed, cut up and bunched into the out-row. The unmerchantable part of the log is cut off to shorten the stem length and reduce the chance of it banging against remaining crop trees during bunching or extraction. This also means nutrients contained within the tree's needles, branches and stem are recycled back into the standing trees.

Extraction is with a grapple skidder that reverses down the out-rows to collect the logs.

Cut to length logs are extracted down the out-rows by grapple skidder, minimising damage to remaining crop trees.

There is also the potential to production thin some Douglas fir stands and the crew in conjunction with advice from PF Olsen, is weighing up the option of purchasing a forwarder.

If this stand had been left unthinned, suppression from the high stocking would have prevented the production of higher value large sawlogs. Not thinning the stand would have also increased the incidence of 'black' or bark-encased knots, further reducing the value of the stand at harvest time.

Whilst not appropriate in all circumstances, well-managed production thinning in selected situations can not only avoid costly thinning-to-waste but also provide modest revenue and still result in the production of high value logs at harvest. If you think you may have a stand suited to this type of operation please contact your local representative, or call us on FREEPHONE 0508 PFOLSEN (736 5736) or email us as info@pfolsen.com or visit our website www.pfolsen.com.