Mikko ja Matti Vikström Oy carries out thinning projects mainly for the state-owned Metsähallitus in the Pudasjärvi area. Already 17 years ago, the company made a decision to equip their two lightweight, 10-tonne forwarders with multi-purpose harvester heads. The experience has shown that this choice was perfect due to the fact that the soft soils of their typical logging sites cannot withstand several machine passes.
– In 1997, me and my brother Mikko were forwarding timber cut by a logger and started to think how we could employ ourselves and our machines also for the summertime. After making some experiments, the only reasonable solution was to have a lightweight forwarder, sturdy crane and multi-purpose harvester head, Matti Vikström recalls.
Matti Vikström tells that they also tried the conventional harvester-forwarder machine chain but this proved to be unsuccessful, at least on the soft peaty soils and with the stand structures typical in the Pudasjärvi area. The amount of timber collected from thinning stands is not enough to operate two machines profitably.
Nisula 425C, the harvester head at the end of the crane, is a multi-purpose harvester head equipped with grapple arms, and it makes the cutting, delimbing and loading of timber a smooth operation. The control system has a diameter limit set for the utilisation of the grapple arms during harvesting operations. Clever automatics enable a firm grip at all times during felling, feeding and processing operations.
– The use of this multi-purpose head does not really differ from using a conventional harvester head, and the control system works nicely, Matti Vikström tells.
Thanks to its compact size, it is easy to take the head to the target tree without damaging the trees to be left. The Vikström brothers view that the reliability of the head is very important for profitable thinning operations. Nisula 425C has met their expectations since it has not required any actual repairs or welding. Even the number of hose failures is low – the cylinders of the head do not move lengthways which significantly reduces the risk of hose damage.
The Vikström brothers use their machines in two shifts. They replace each machine with a new one approximately every four years. By this time, the machine can have up to 14,000 hours under its belt. The new machines are always delivered via Nisula factory where the multi-purpose harvester head is installed and adjusted according to the Vikström brothers’ wishes.
Matti Vikström finds the measuring device of the Nisula head to be extremely reliable. He tells that the device measuring from the delimbing knives has not caused any problems whatsoever. The NCU3X system of the Nisula head has the length and diameter measurement function, cubic volume measurement function and value scaling function.
Aimo Ojala works as a machine operator at the Vikström brothers and he is convinced of the superiority of the multi-purpose harvester head in thinning sites. Aimo has used a multi-purpose head for some 20 years and finds it very operator-friendly. And he definitely knows what he is talking about because he also has extensive experience in using conventional harvester heads. As a rule, the sites can be completed in one go that is a major advantage on soft soils. Aimo estimates that the 425C is very useful when logging trees with cubic volumes from 300 to 350 litres, and even bigger stems do not cause any extra trouble. The grapple arms in the centre section of the head provide additional support and ensure a tight and secure grip of larger stems as well. These grapple arms increase the versatility of the head when processing, for example, forked and fallen trees. Picking up the stem from the ground for processing is quick and easy with the grapple arms, reducing the risk of damaging the knives and feed rollers.
Nisula 425C improves the cost-effectiveness of thinning projects. Compared with the previous C-model, stronger drive motors increase the feeding capacity by 20%, and the new, machined front knives provide improved delimbing efficiency and durability as well as larger delimbing diameter.
Nisula 425C, the harvester head at the end of the crane, is a multi-purpose harvester head equipped with grapple arms, and it makes the cutting, delimbing and loading of timber a smooth operation.
The amount of timber collected from thinning stands is not enough to operate two machines profitably. That is why the Vikström brothers equipped a lightweight forwarder with Nisula 425C multi-purpose harvester head.
Mikko says that also the capital costs of the multi-purpose head option are reasonable when compared with the conventional machine chain.