Westonbirt Arboretum, near Tetbury in Gloucestershire, is famed for its autumn colours. But here, as anywhere else, trees sometimes have to be removed, be it because of old age or damage. And at this point, there is usually a need to remove the stump as well.
At Westonbirt, staff use a tractor-mounted stump grinder but the choice on the market is huge. There are hand-held models, pedestrian-operated push machines, self-propelled units, tracked machines and even radio- controlled versions.
Conditions on the day of the test were dry and sunny.
With the tracks retracted, the width is just 67cm. Extending the tracks gives a width of 100cm for stability. So this is a machine that can creep through small gaps and yet take slopes and rough terrain in its stride.
The engine is a Lombardini diesel and it seems noisy after the Hatz Silent Pack. Although there is also a manual version available - and it is one of Predator's best-sellers - we again narrow in on the radio-controlled version to operate everything except the rpm. Townsend quickly gets the hang of it.
"The functions are easy to learn; it comes naturally. I don't think anybody would struggle with the radio control. It does exactly what you expect it to do," he says.
"There are a few little quirky bits - like a fraction of a second delay when you raise or lower the cutting wheel - but that's something you can get used to very quickly."
Townsend also likes the fact that the radio control means operators can position themselves wherever it is best for view and safety. And being self-propelled, the grinder can access the stump from any angle.
"There are no restrictions as there are for a tractor-mounted machine," he comments.
Like other Predators, the 28R is fitted with the quick-change Multi-Tip teeth system. And like other Predators, the 28R has safety built in. The wheel, for instance, stops in just 1.5 seconds.
We found the 28R to have a good degree of slew and the arm lifts up high - cutting height is a massive 80cm. This could be a good machine for windblown stumps.
The 28R and its manual version should prove ideal for tree surgeons. We tested the machine on hard cherry stumps and, although the machine was pushed to the maximum, the Predator 28R comfortably took a 6mm skim off each time.
THE REVIEW PANEL
Ben Jones, arboreta specialist, Westonbirt Arboretum
Justin Litten, arboreta specialist, Westonbirt Arboretum
Richard Townsend, arboreta specialist, Westonbirt Arboretum