Comparing logging system productivity and costs in conventional and energywood harvesting from pine plantations

The cost effectiveness of the system when producing different products from the same stands was examined.

A logging system operating in predominantly loblolly pine (Pinus taeda) that consisted of a tracked feller-buncher, grapple skidders, tracked loaders, pull through delimbers and a shovel; was use to compare the following three scenarios in clearcut felling:
 

• A conventional full-tree roundwood system where sawtimber, chip-n-saw, and roundwood were produced for sawmills, chip-n-saw mills and paper mills.
• An integrated roundwood and fuel chip system where merchantable and non-merchantable stems were felled. The stems were separated by the feller-buncher. The skidders would then extract the merchantable stems for processing into roundwood and the non-merchantable stems were taken to the chipper.
• A fuel chip system where all merchantable and non-merchantable stems were felled and skidded to a chipper.

The following productivities were achieved:
 

The results showed that the onboard truck conventional system roundwood costs were the lowest at US$ 9.35/t. The roundwood costs for the integrated system were higher at US$ 10.98/t. This was due to decreased felling and skidder productivity. Onboard fuel chip costs were US$ 17.93/t for the chip system and US$ 19.19 for the integrated system. Low skidding productivity contributed to the high costs in the integrated system. The results showed that the prices for energywood would have to substantially increase before roundwood production was sacrificed to produce energywood.

This article, titled “Harvesting productivity and costs when utilising energywood from pine plantations of the southern Coastal Plain USA”, was published in the Biomass and Bioenergy Journal, Vol. 52 (2013). The authors were J Conrad, C Bolding, M Aust, R Smith and A Horcher. Source: http://www.sciencedirect.com/science/journal/09619534