By Ko Oishi, NSCF Farm Co-ordinator.
One of my favourite annual activities is to harvest and process bamboo as it brings people together, and it is such a great skill sharing session. It’s a lot of work but it pays off as bamboo yields so many different products. It’s a relatively untapped resource; too often we see running bamboo spreading to native bushland, on side of the road, in council parks completely unharvested. Bamboo stakes and poles are often being sold at large hardware stores, imported from south-east Asia, when they are actually growing rampantly on our own roadsides of Brisbane.
It’s important to note that in its natural habitat, and in a balanced ecosystem, most plant species are controlled by herbivores (insects, mammals), disease, competition, etc. In societies where bamboo has been grown for a long time, the resource is better integrated into day to day living and people know how to utilise it, whether it be for construction or culinary.
At Northey Street, bamboo is generally harvested during the dry season (anytime between May-Sep) and it’s important to choose ones that are at least a few years old because the new growth (1st year growth) is prone to splitting and won’t keep well for construction. The new growth is indicated by leaf sheaths on the lower nodes, and often have white powdery substance so they’re easily identifiable. Make sure you use gloves and long sleeves as the hair on the bamboo can irritate your skin, and the bamboo fibre is extremely sharp!
For those that are interested, I encourage you to do your own research on the harvesting season and its reason, most appropriate treatment method, maintenance, etc.
Bamboo is often planted by those that have no intention of harvesting it but planted due to its fast-growing nature (i.e. screening undesirable views, pollution, and noise barrier) and for their aesthetics. For its various by-products, it’s also often favoured by permaculture practitioners and the like.
It’s important to think of ongoing management if you want to plant bamboo. When bamboo isn’t harvested annually, it gets harder for ongoing maintenance as the new growth will impede access to the mature ones. Generally, for clumping bamboo, new growth emerges outwards in a concentric pattern, which means the new growth will often grow on the outside of the perimeter, so without regular pruning and harvesting it can quickly get out of hand.
Once a year, I walk around the farm and spray paint the ones that need to be removed. The reasons could include for general maintenance, to give more space to new growth, and to use it around the farm for various activities (i.e. Winter Solstice!).
As you can see from the photos, bamboo for construction should be cut as close as possible to the bottom, and flush with the node to prevent water pooling between the nodes. Harvested bamboo poles are processed by removing lateral branches (for making stakes), and sometimes the internal nodes knocked off using a steel rebar.
In an ideal situation, you’d dry the bamboo poles in a semi-shaded area (never direct sun as it can cause cracking) for a few weeks.
Sometimes these poles are treated using heat (fire in our case) carbohydrate is “cooked” (or crystalise) to make it less palatable to the borers. We’ve also used bees wax mixed with gum turpentine to treat bamboo at the farm after cooking the sugars.
There is also the ‘water leaching’ method where we wash out or ferment the sugars that would otherwise attract the borers. We haven’t done this method yet but something I’d like to try this year in Breakfast Creek!
We’ve also tried using boric acid and borax to treat the poles, but we have moved away from this method of treatment as we wanted to explore more sustainable products. Strips of bamboo are made using a bamboo splitter. The splitters can probably be welded together using old steel, but I got mine from Japan.
Whilst there is a bit of maintenance, bamboo offers such an amazing array of products. It offers beautiful screening, noise, and a pollution barrier. One study by Leeuwen (2016) showed that a bamboo barrier of 5 metres in height and a width of 6 metres offers a similar noise-reducing effect of a 3-metre-high solid wall), construction materials, musical instruments, art and craft supplies, food, and so much more!
So, if you’re ever thinking about volunteering at Northey Street, there’s always a lot to do during this time of the year, including harvesting and processing bamboo! So come and say g’day.
Check out our current volunteering opportunities here.