How to 'spalt' your own wood
East Gippsland mushroom grower Josef Sestokas is also a long-time woodworker, and is shown here sawing spalted silver birch.
The sight of wood with beautiful, almost feline ‘leopard spot’and 'tiger stripe’ markings has captured the imagination of woodworkers forever, it seems. In Australia we value our native Tasmanian tiger myrtle and blackheart sassafras, but mostly these markings are associated with northern hemisphere woods such as maple and beech.
Wood with mould-induced ‘spalted’ figure occurs naturally, however it is possible to make it happen yourself. We spoke to Victorian mushroom grower and woodworker Josef Sestokas, on combining both worlds and teaching others how to do the same.
‘Zone lines’ and areas of changed colouration in a spalted beech bowl
How did you find yourself in the world of spalting timber?
It pays to keep checking up on recent developments in fungi, and I stumbled across the work of Dr Seri Robinson, who with her colleagues, are the leading people in spalting, as far as I can tell. Seri has published four books, two of which are about spalting, and I own both. They are fairly new in the scheme of things. Most of the research behind this is less than 10 years old. We’ve gone on to join the Northern Spalting Cooperative, which funds further research and opens up extra information and resources to cooperative members.
I believe you are a specialist grower of fungi?
Our mushroom growing business started as a hobby around 2019. We realised there was an opening to start a business, so we got ourselves established quickly in gourmet and medicinal mushrooms. The business, Flooding Creek Fungi, has gone through one major expansion, but it’s still a small family business. You don’t need a lot of space to grow just over 100kg of mushrooms a month, which is our average output.
Another example of spalted beech
Can you tell us a little about yourself?
I was a police officer for just over 40 years and have loved working with wood in my spare time – that includes making three queen size beds and our bedside cupboards which include some marquetry. I’ve owned nearly every Triton tool! So I appreciate beautiful timbers and know a bit about fungi. It’s nice to be able to understand the science behind spalting. My father grew up in Lithuania, pre-World War II. They had a lathe in the middle of the farmhouse, where my grandfather made furniture to supplement the meagre farm income, so maybe it’s in the blood too. My father was a wizz with woodwork.
What is spalting?
Spalting is basically any colour in wood produced by fungus. That can be bleaching, colouring with pigments, or ‘zone lines’. Zone lines usually demarcate boundaries between two fungi competing for nutrients in the same tree limb or trunk.
How hard is it to get the spalted effect that we mostly admire on European and North American species?
Most of the guidance around spalting applies to timber and fungi from the Northern Hemisphere, and in particular from North America, although there is a body of work from Peru.
The challenge for me is to match Australian fungi and timbers. We do have some of the same fungi used in America, and we have some European trees, plus access to some American timber. I’m running my own trials to see what works best. There is one way to instant success, and that’s to apply pigments from fungi to a finished piece, selectively. I have some pigments supplied by Dr Robinson.
Can native Australian woods be successfully spalted?
Yes. It does occur naturally here in some of our native timbers and Australian woodworkers have been using ‘found’ spalted timbers for years, plus trying to make spalting happen. The last Australian article I could find on spalting in Australia was from 2000. Tropical timbers are more difficult to spalt. Dark timbers don't lend themselves well to spalting. I’ve seen some lovely pieces done by Gippsland woodworkers on a variety of native timbers, however.
Do specific types of fungi spores need to be used?
Spores are rarely used to propagate fungi, commercially or for spalting. It’s much better to buy spawn or to strike a culture on an agar plate from a tissue sample. Think of it as taking a cutting from a plant.
Above: Turkey Tail fungus (Trametes versicolor) is often used to induce spalting in combination with another species.
Finding the right fungi is the trick. They can be elusive. One of my target species of spalting fungi, the Green Elf Cup, only appears briefly when it is raining, so some of it comes down to luck too. Matching competitor fungi is necessary to achieve zone line spalting.
How long does it take to get a result?
It used to take years, when woodworkers piled logs in a damp shaded spot. Depending on the method, three months is possible, and with application of pigments it can be instant.
What led you to start offering workshops in spalting timber?
We like to grow a love for fungi, for nutrition, and in the wild as nature’s recyclers, through citizen science. It seems a logical extension of what we do, to offer spalting workshops, and one day we hope to offer for sale combinations of suitable fungal cultures on agar plates that keen Australian woodworkers can apply to their own choice of timbers.
Josef Sestokas is running a workshop on Tuesday, June 27, 9:30am–12pm at TAFE Gippsland, Forestec Campus. This event is part of the 2023 East Gippsland Winter Festival, which runs from 9 June – 9 July. The workshop costs $135, purchase tickets online at events.humanitix.com/spalting-workshop
Photos: Josef Sestokas