In August 2023 a nor’wester took a limb off my macrocarpa, the 25-metre one on the boundary of my Sydenham place. It was about 350 mm through at the break and 9 metres long, and it came down across the back lawn without touching the fence, which I still count as luck. The arborist who cleaned it up offered to chip it. I said no, I would keep it for the fire, and he gave me the look of a man who has watched a lot of homeowners discover what a tonne of green macrocarpa actually involves.
Two winters on, having also helped a cousin cut up a fallen shelterbelt tree outside Rolleston, I have a fair idea of what macrocarpa firewood is worth, in dollars and in Saturdays.
How much wood is really in a tree
People look at a big limb and see a winter’s heating. My 9-metre limb, once the brash was stripped off, gave about 1.6 cubic metres of thrown, split firewood. That is a bit over a third of what a Canterbury house with a modern wood burner gets through in a winter, which I put at 4 to 5 cubic metres. Green macrocarpa weighs around 800 to 900 kilograms a cubic metre, so I moved roughly 1.4 tonnes in barrow loads. The Rolleston tree, a whole 20-metre shelterbelt macrocarpa that had windthrown, produced about 7 cubic metres from the trunk and main limbs.
Rule of thumb from both jobs: a mature macrocarpa yields roughly 0.3 to 0.4 cubic metres of usable firewood per metre of trunk over 400 mm diameter, and the limbs add perhaps a third again. Anything under 100 mm is kindling or chipper feed.
Splitting it
Straight trunk rounds split cleanly with a 3 kg maul and a wedge, and the smell is the best part of the job. Limb wood and anything near a fork is stringy and full of included bark, and it will swallow a wedge and give nothing back. For the Rolleston tree we hired a 25-tonne hydraulic splitter for two days at NZ$140 a day and still had a pile of knotty rounds that went to a neighbour with an outdoor fire.
Cut rounds to 300 to 350 mm for a standard wood burner and measure your firebox first, because a stack of 400 mm rounds you cannot fit is an annoying thing to own. Split green if you can; macrocarpa gets tougher as it dries.
Seasoning takes longer than you think
Fresh macrocarpa sits around 50 to 60 percent moisture content. Wood burners want under 25 percent and ideally under 20. In Canterbury, with a hot dry summer and a stack that gets sun and the nor’wester, split macrocarpa reaches that in 12 to 15 months. In a shaded corner behind a garage, 18 months to two years. A NZ$40 moisture meter takes the guessing out of it; split a piece and test the fresh face, not the weathered outside.
Stack it off the ground on pallets, one row deep, top covered and sides open. Wrapping the pile in plastic grows mould. Burning it damp fouls the flue, halves the heat output and puts more smoke over the neighbourhood, which in a Christchurch winter airshed is not a small thing.
What it is worth
Delivered, seasoned macrocarpa in Canterbury sells for around NZ$130 to NZ$180 a thrown cubic metre, against roughly NZ$100 to NZ$140 for radiata pine and NZ$200 or more for bluegum or old-man pine. So my 1.6 cubic metres was worth perhaps NZ$250 on the open market. Against that, chipping would have added about NZ$150 to the arborist’s bill, so keeping the wood saved me around NZ$400 in total, for two full days of cutting and splitting and most of a Saturday stacking. It is not a wage. It is a hobby with a heated outcome.
The one thing not to do is expect the tree contractor to knock money off for the wood. Firewood merchants buy by the truckload at a fraction of retail, and a single suburban tree is not worth the diesel to them. An arborist who leaves the rounds and skips the chipping is doing you a favour, not a trade. I went through the same arithmetic when a relative was removing a redwood beside a lakefront house and hoped the timber would pay for the job; redwood is worth even less as fuel.
One last point for anyone moving wood between regions. Untreated firewood carries bark beetles, wood borer and sometimes worse, and the Ministry for Primary Industries publishes guidance on what not to shift where. A boot load from Rolleston to a Christchurch shed is fine; a trailer of anything from the North Island or from a block with a known pest is a different matter.
Frequently asked questions
How long does macrocarpa firewood take to season? Split, stacked off the ground and open to sun and wind, 12 to 15 months in Canterbury. In shade or a closed stack, 18 to 24 months. Aim for under 20 percent moisture on a freshly split face.
Is macrocarpa good firewood? Yes, for a closed wood burner. It burns hot and fairly clean once dry, and lights easily. It spits and throws sparks, so it is a poor choice for an open fire without a screen.
Will a tree removal be cheaper if I keep the firewood? Only by the cost of chipping and cartage, typically NZ$100 to NZ$300 on a suburban tree. Nobody pays you for a single tree’s worth of green rounds; the resale value is far less than the labour of processing it.