At roughly 36 tonnes with a tracked base, the 859M sits at the heavy end of purpose-built felling rather than in the crossover territory occupied by excavators carrying shears. Everything in its published specification points the same way: 373 kN of tractive effort, 494 litres per minute of pump flow and an 870 litre fuel capacity describe a machine designed to work a full shift in demanding ground rather than move between small jobs.
That is a commitment, not a feature list. A machine of this class only makes sense where felling hours are measured in thousands per year and the chain behind it can absorb what it produces. Where either of those fails, a smaller carrier with a shear will usually beat it commercially despite producing far less per hour.
Indicative published manufacturer and distributor information. Confirm every figure, lift chart and hydraulic requirement with the manufacturer or authorised dealer before purchase.
A specification table tells you what the machine is. This is what each of those numbers means for the work you would put it to.
Beyond the standard buying criteria for the class, these are the questions this machine in particular raises.
Depreciation dominates. Applying the guide's ownership model — capital less residual, spread across the ownership period and divided by productive hours — a machine in this class carries a fixed hourly cost that only becomes defensible at high annual utilisation. That is why the commercial-fit note points at 3,000-plus productive hours rather than at any specification.
Disc-saw consumables are the variable most likely to differ from a model built on someone else's experience. Tooth consumption moves with timber type, soil contact and operator technique, and it is worth tracking per tonne rather than per hour so a change in it is visible.
The 870 litre fuel capacity is a productivity figure as much as a cost one: fewer refuelling stops on a remote coupe is recovered production. Fuel per tonne, not fuel per hour, is the number to compare against alternatives.
Confirm transport width and height with the head fitted, and whether the head has to come off to travel. On estates with scattered coupes, machine moves can consume more days per year than breakdowns do.
The published head options differ in accumulation behaviour as well as capacity. Witness the specific head being offered working your dominant stem class rather than accepting a quoted stems-per-hour figure.
In an interdependent chain, parts availability and technician access convert directly into production days. Ask what is held locally and what response is guaranteed in writing before comparing purchase prices.
The highest-volume softwood configuration, and the one with the greatest exposure to bottleneck mismatch. Either a full-tree chain or a cut-to-length pair, depending on terrain, mill requirements and contamination tolerance.
The one package where the offtake agreement must precede the fleet decision. Chip specification, moisture limits and contamination tolerance determine whether the correct machine is a chipper or a grinder.