Iron Tester, Alister Hudson.

As we venture into the deep south between Invercargill and Fiordland in search of an eight-wheeled Komatsu harvester at Bluewood Thinning’s operation, we notice a lot of the trees scattered on flat farmland seem to be about 15% taller than similar trees in the North Island. The Iron Test team throws around various theories as to what might cause this.

The long rolling hills of Southland look like ideal ground for growing Douglas fir trees too, but that theory doesn’t pan out once we get in the forest. Maybe after a thin they will come right? Going by the stem quality going out on passing log trucks to the port, these guys at Bluewood Thinning’s are definitely thinning out the correct trees. 

The stand is around 28 years old, so once this thin is complete they’ll have another 17 years to pack on some decent timber and the growing room to do it before they reach the target age of 45.

The Ernslaw One-managed Gowan Hill Forest is actually a bit steeper than rolling in places and we need four-wheel drive to avoid loosening up the gravel too much on the hills for the log trucks. 

The terrain has a bit of rock and this was ripped pre planting. It is a bit bumpy looking down the rows in the thinned stands.

At first sight, the Komatsu 931 XC is a different-looking machine. It clearly demonstrates some of its key advantages on the bumpy ground as it is driven out to the road with the eight wheels all hugging the terrain like a centipede, instead of the bouncing you would expect in a four- or six-wheeled machine. 

You can barely see where it’s been either, even in muddy conditions, so the low ground pressure designed into this unit is proving itself.

The cab is also tilted to level with the terrain, improving the ride and reducing fatigue on the operator.

Finding the perfect pro head

We catch up with Paul Roche from Komatsu Forest to see how this machine came to be here in the deep south. 

“Back in June 2019 we sold the first Komatsu rubber tyred solution to CMH Contracting in Rotorua after a visit to Australia,” Paul says.

“This was a 951 with a S172 head. Our thoughts were, let’s get the biggest we can get for New Zealand’s timber. We had viewed an operation in Australia and the form of the trees was really nice, very little branching and these seemed to almost snap off when going through the S132 head.

“So, based on our thinking we went as HD as we could – the big 951 along with the S172 was ordered and off to work it went. What a very capable machine and it paved the way for us.

“Based on that scenario we had a great working machine providing excellent data back to the forest owner and contractor. Everyone was happy. We had so much precise data, it was a massive push for ‘where to next’ with base and heads we were to supply going...