Which firewood is best?
Ask the people who know trees best and they'll tell you not to grow trees for firewood.
Grow trees for a list of other great reasons - fruit, nuts, shelter, habitat, erosion control, timber for posts etc - and you'll always have enough firewood and kindling from the prunings and windfall branches and twigs.
HIGHLY-RECOMMENDED FIREWOOD TREES
Manuka self-sows, grows fast, copes with everything - drought, frost, cold, wet, acidic conditions, shade - isn't palatable to stock, gives you a gorgeous honey, and doesn't grow too tall, plus it's excellent as a pioneer shelter tree (its natural role in native bush). You can split it when its green, use the flaky bark for kindling, and enjoy a very hot fire with little ash.
Kanuka looks very similar to manuka but grows much taller. The differences: manuka leaves are prickly, kanuka leaves are soft, manuka retains its seed pods, kanuka doesn't, split manuka is cream inside, kanuka is red with cream. Kanuka also self-sows, and the wood burns long and slow, producing incredible amounts of heat.
This is known in many parts of the world as the best firewood of all. These are fast-growing trees and they need to be pruned or they will get up in height quickly in warmer climates. The young trees are frost-tender, but it's worth persevering with as a shelter in most soil types (even poor ones), and for the wood's long, slow, hot-burning properties which leave little ash behind. The bonus is the tree can easily regrow after pruning and is a dense shelterbelt.
4. Tagasaste/tree lucerne
This tree isn't around for a long time - it lives for about 10 years or so - but works very hard for you in that time. It's a fast-growing pioneer shelter tree if you're setting up an orchard or want to protect longer-living shelter trees, it breaks down to make great compost, the foliage is a highly nutritious stock feed (birds love it too), it's good to coppice, and it fixes nitrogen in the soil. Even better, after year 4 it will provide a lovely firewood - even finger-sized branches are worth burning.
Manuka copes well in drought, frost, cold, wet, acidic conditions and shade. Photo: Likelike-123RF
5. The no-firewood tree firewood block
When NZ Tree Crops Association magazine editor Sheryn Clothier was planning her block, she got some great advice: plant fruit trees and you'll never need to plant firewood trees.
One hundred and fifty fruit, nut and fodder trees later and Sheryn has found that advice is correct, and the bonus is that fruit and nut trees are hardwoods so they have excellent burning qualities, and the aroma of these woods when they burn is said to be outstanding.
Sheryn's tip: save your grape prunings, wait for them to dry out, then use them as fire starters.
WHAT NOT TO PLANT
Pine (Pinus radiata) isn't a good choice. It grows quickly and becomes a nuisance, it doesn't allow other plantings to grow under it or anywhere near it, it isn't that great as firewood compared to other options, and if you live near a commercial pine forest you may be able to get a permit (for a fee) to cut up their prunings for firewood. Some forest companies don't allow this for health and safety reasons.
TIPS TO DRYING FIREWOOD
1. Cut your firewood in spring or early summer so it gets at least 6-9 months to dry out; if you cut it in autumn or winter, it won't be dry enough to use until the following year. Some types of wood like oak or larger cuts of wood can take a year or more to dry.
2. Cut and split your wood into the right size and length for your woodburner first-time. This gives it more surface area so it dries more quickly, plus it means it's ready to use and you don't have to process it again.
3. The best place to dry freshly-cut firewood is outside. If you throw it straight into a wood shed, it will take twice as long (18-24 months) because it's not getting assistance from the sun or air movement.
Fruit trees are hardwoods so they have excellent burning qualities. Photo: Sturmschaden-123RF
4. Stack firewood in a single row up off the ground so the sun and breeze can draw the moisture out the cut ends - most wood has a 30-50% moisture content when cut and you'll need to get it down to around 15-20% before you can burn it efficiently. Wood that's too wet creates a lot of smoke and if it burns at all it will produce little or no heat.
5. You can leave drying firewood uncovered but it does help if it has something sitting over it acting as a roof, eg a length of roofing iron. These shouldn't sit directly on the firewood - lay long lengths of timber or old pallets on the ground and on top so any cover you use is sitting up off the firewood.
These values are based on an average moisture content of 20 per cent. Remember that firewood is sold as a 'thrown measure' so will reduce by one-third in volume when it is stacked. Source: FirewoodNZ, www.firewoodnz.co.nz
HARD WOODS VS SOFT WOOD
The longest-burning firewood that produces the most heat will be a hardwood. But confusingly that doesn't necessarily mean it's a wood that is hard to the touch. Balsa, a very light, easy-to-work wood, is a hardwood.
Hardwoods are trees that reproduce by producing seed with some sort of covering (eg, acorn, apple), and are deciduous. The wood will be heavier than a softwood and will take longer to season or dry out (around 18 months).
Softwoods are evergreen and their seeds have no covering, eg pine trees. The reason people use them is because they tend to be easier to cut and split, and they dry more quickly (in 6-12 months). However, they burn much faster than hardwoods so you need around twice as much to get the same amount of heat.
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