The two-stroke engine may not have long left as the workhorse of choice in New Zealand’s silviculture crews. With each passing year there are either small developments or big breakthroughs in battery technology. The power potential of electric motors needs no explanation with the current popularity of E-bikes, formula E racing and new hybrid forestry equipment. With most construction and consumer hand tools having been battery- or electric-powered, is it now time for our forestry equipment to be the same?
The School of Forestry at the University of Canterbury was generously given two Stihl MSA 220C battery-electric chainsaws by Stihl New Zealand. Within the scope of a student summer project, and with support of Forest Growers Research, the saws were tested to see if they have what it takes to be an equivalent or even improved alternative to the petrol chainsaws used currently by silviculture crews. Three crews in the Canterbury/West Coast region were asked to trial the new chainsaws over two days of thinning, spending half a day with the electric and the other half with their own petrol saws, both days.
Many interesting findings were made, first of which being that the thinning chainsaws of choice for the crews were heavy and powerful, capable of felling full-sized trees (Stihl MS 462 and 500i’s fitted with 18- and 20-inch bars). The electric saws provided were lighter and less powerful, but still sufficient to fell trees at mid rotation (up to 35cm diameter). This power difference, along with the shorter bar length of 16 inches, did lead the electric chainsaws to achieve a lower count of felled trees per hour.
So, should we forget about the electric chainsaws for another few years then, until the technology is ready to actually match petrol power? The answer should be no. These new chainsaws may have less grunt than those preferred by our silviculture crews, but they also have some undeniable advantages. A really big one is noise. They produced a weighted equivalent average of only 87.2 decibels compared to the 100 decibels of a petrol chainsaw. This is a stark difference as decibels work on a logarithmic scale, making the electric saws over 10 times quieter. No more thunderous roar, but instead a quiet hum. You could operate one of these saws all day, only needing the most basic hearing protection (class one), and they are close to not needing any protection at all under Worksafe regulations.
Having a motor rather than an engine gives another big advantage too. The operators in our study noticed the lack of vibrations, reducing risk of Hand-Arm Syndromes by getting rid of the piston action. Not having any exhaust fumes was appreciated by the crews, as well as the planet. The weight of the saw in hand is a pleasant surprise too. With a battery in the saw it weighs about 5.1kg, a decent drop from an MS 500i weighing around 8kg with a full tank of fuel. But what if there was no compromise on power and...