Getting Sunlight into the Orchard Floor
It’s a topic we’ve all heard time and time again but one that doesn’t really have a definitive answer what is the best way to maintain production while keeping sunlight into the orchard floor to enable plant growth?
Over the years pruning has gone through many stages of evolution from using mechanical hedgers to no hedgers, manually pruning and last but no least nothing at all.
All forms of hedging come at a cost so let’s look at the methods.
Mechanical Hedger
Mechanical hedger cuts down the side of 1 tree as it makes it way along the tree row and then genuinely the other side of the tree as well. The downside of hedging this way is all lateral branches are trimmed causing the relaxed look of a tree to be upright and the part of the tree which flowers and has a good chance of pollinating is trimmed by the hedger resulting in potential yield loss. Generally hedging cuts off about 15 to 20cm of a lateral branch and is done every two years. What also happens with the age of a tree when hedging every two years is production ceases to increase due to the cutting of the branch and the growth of the tree height competing with other trees which also creates dead centres of the tree due to excessive growth of hedged lateral branches causing what is known as the “Green Wall of Death”.
No Hedging
Another method if you say is doing nothing at all...no hedging, no pruning, just let the tree grow and let it be. Know this a common method as it creates little effort to do and as most people are aware people like the easiest and cheapest option while not the most beneficial it can have benefits in the short term but long term it creates a management problem that will come back to bite you. The downside to no hedging/pruning is once the lateral branches touch each other the lower canopy of the tree dies off due to low light this causes the only growth to be at the top of the tree which over consecutive years diminishes grass growth, productivity, continual wet orchard after rain events, increase pressure on machinery to push higher to reach fruiting wood.
Manually Pruning
This method is by far the most labour intensive but also the most beneficial to your orchard while there is more of a cost to maintain the orchard in this manner it is by far the best long term method to maintaining productivity, tree height management, grass, Carbon build up in the soil by chipping pruned limbs to base of tree, new fruiting wood closer to base of the tree & the most important aspect increase sunlight in and around the tree by creating light pockets.
The secret to Manually Pruning is knowing “How Much Do You Prune.” A good rule of thumb is no more than 20% of the tree canopy this allows for the compensation of the shedding period of the tree which happens around the November/December period of nut sizing in the orchard.
Another aspect to take into consideration when pruning is the where and how. There is no right and wrong way of pruning limbs it’s more of a tree by tree process and whereas in pruning. “Doing Something” is better than nothing approach. You can't expect change if you don’t do anything? A good rule in pruning is if you manually prune a lateral limb come with-in 1.5 meters from the lateral end and manually prune the limb to allow the light to come into the orchard and capture light within the centre of the tree to allow new growth which in turn allows five years before manually pruning will need to be done again on that limb allowing three years of nut-set to occur whereas manually hedging a limb every two years doesn’t allow fruiting wood to set into nut set. Very counterproductive.
I hope this sheds some light 😊on our understanding of how to improve light and productivity onto the orchard and if any questions need to be answered please call me and I'll assist where possible.
Yours sincerely,
Garth Templeman
Grower Liaison
Waliz Nuts PTY LTD