This piece is an extract from our A View from the Forest (previously Forestry Features) newsletter, which is emailed out at 4PM every Wednesday with a round-up of the week's top stories. 

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THIS year marks four decades since the introduction of the first Valment 901 – one of the world's first single-grip harvesters designed from the ground up with a specific harvester chassis. With the 901 eventually came the Komatsu Stability Concept, which still helps machine operators work safely and productively, 40 years on.

Today's forestry machines are high-tech tools that combine strength and smart technology with innovations that are specially adapted for forestry. Mechanised forestry took off around the 1980s and since then a lot has happened in terms of technological development. But one thing remains the same, and that is the stability concept, which was launched in 1984 under the Valmet name.

The Valmet 901 survives today in the form of the Komatsu 901 The Valmet 901 survives today in the form of the Komatsu 901 (Image: Supplied)

The breakthrough came when Valmet engineers wanted to build a harvester from scratch, rather than on a modified forwarder chassis as was common at the time. They developed a prototype for a thinning harvester, but the difficulty was stability. After many tests, they came up with the solution that is still a hallmark of Komatsu harvesters today.

“We mounted a 935 head on the machine and there we had it, the Valmet 901, one of the first purpose-built single-grip harvesters designed from scratch as a harvester,” Ola Boström, design head at the time told Komatsu's in-house magazine in a recent interview. “And since the machine was small and performed well in thinning, it proved a success. From that point on, development work continued, resulting in machines with six wheels, then even larger machines – and finally machines with eight wheels.” 

The concept consists of an innovative swing axle that improved stability by locating the engine at the rear. This design, together with a unique hydraulic levelling solution, allowed the machine to navigate difficult terrain with both high precision and efficiency. The tilt cylinders were linked to the swing axle stability cylinders, which meant very good machine control during work – even in steep terrain.

It sounds complicated, but in practice it means that if the crane is working far out from the machine and carrying a heavy tree, two stabilising cylinders work as an automatic counterforce to maintain stability. 

Four decades later, Komatsu's stability concept shows that true innovation not only stands the test of time, but continues to make life easier for operators, whatever the terrain.