There have been two previous
NZ Logger articles focusing on skidder operations this year.
The first reviewed the effectiveness of extending the operating range of a skidder operation in challenging terrain and weather conditions with winch-assist at NJP Logging’s Victoria, Australia, operation. The second examined a very high production stem crew, Rotorua-based Trimax Logging, working in the Tarawera Forest.
In this final study we look at a skidder crew faced with another type of challenge – the salvage harvest of windthrown stands. As stand damage to plantation forests becomes more frequent, it becomes more important to understand the impact on logging system productivity.
The Otago/Southland region has been hit hard by a sequence of storms, the most damaging a severe wind event in late October 2025, affecting approximately 1500-2000ha of plantation forest. For example, City Forests, which manages over 20,000ha in the Otago region, was impacted with over 500ha of its estate being damaged. After the storm, the company quickly pivoted to salvaging as much of the windthrow as possible.
Machinery configuration
Ollerenshaw Logging, with owner Kelvin (Olly) Ollerenshaw, was one of the crews moved to help salvage a heavily damaged stand. In terms of the machine configuration, at the time of the study, in late January this year, two Sumitomo 300TLs with Satco 630 heads were felling and bunching in the cutover. A Sumitomo SH240 was shovelling and building surge piles for easier access from the extraction trail. The primary extraction was with a Tigercat 635G skidder, with another identical model as a ‘spare’, used to boost productivity when enough trees were on the ground and the processing on the landing could keep up.
A Sumitomo SH370, fitted with a Waratah 625C head, was processing on the landing. Also working on the landing area was CAT 538LL, mainly loading trucks, as well as a two Sumitomo SH250s fleeting and/or shovelling as required. A Sumitomo SH350 was also on site as a back-up processor.
In addition to crew owner Kelvin Ollerenshaw, the crew was made up of Jared Melvin, Konnar Melvin, Poldark Jones, Nash Jones, Ethan Hippolite, Craig May and Jacob Gillies.
The operation was studied while working in Tokoiti Forest, just south-east of Milton, in Otago. Competently supervised by Joseph Graham and Rodney Jordan of City Forests, the simple harvest plan was to quickly salvage as much of the damaged 29-year old Radiata Pine stand as possible.
Long extraction distances
By targeting the damaged areas, and not having the time to improve the infrastructure, such as by extending the roading network, the harvest area was relatively long and narrow. This resulted in extraction distances of over 500m to the back of the block. The primary skidder was operated by the newest addition to the crew, Jared Melvin’s son, Konnar. At the time of the study, Konnar had only just joined the crew, making a shift from scaffolding to try his hand at logging.
Using GPS units in the skidders, the system was studied over a two-day period by University Summer Scholarship students Yotam Perchig and Noa Visser, with 139 cycles...
