Figures show worth of fixed felling heads

WE NEVER GOT TO SEE ANY FIGURES WHEN NZ LOGGER VISITED the CMH crew in Nelson to observe how the introduction of fixed felling heads was reducing stem breakages and delivering a wider range of cuts.

But at the HarvestTECH 2019 conference in Rotorua, CMH co-owner, Nathan Taylor finally unveiled some of the numbers to prove the value of swapping from a dangle head to a fixed one.

Information derived from the STICKS software system that has been measuring the performance of the Timberpro 765D and its KF800 felling head since they were introduced last year clearly shows the crew has increased the number of posts it is able to cut from 25cm diameter wood compared to when they were using a dangle head.

What that means is the crew is now recovering full length stems with few, if any, breakages from the steep slopes in the Golden Downs and capturing the prized smaller diameters that can be sold to post mills. With the fixed felling head lowering trees to the ground more gently, the tree tops remain intact and provide the processor on the landing with a full range of cut options compared to broken stems that occurred more often with the dangle head.

One slide showed the number of 28m length arriving on the landing was more than double those with a dangle head and the number of 32m lengths available to process was around four times greater.

“We’re definitely getting more of the smaller SEDs than we were before,” says Nathan.

The move to a fixed felling head was prompted after Nathan and co-owner, Hamish Matthews, flew to Australia to see how Gippsland contractor, Andrew Mahnken, was using fixed heads to reduce stem breakages and also bunch better for the yarder.

Andrew Mahnken was at HarvestTECH 2019 to illustrate the benefits, showing photos of neatly bunched wood that make it easier and faster for the yarder to grapple off the slopes.