A little like the Limbo call, “how low can you go?”, the high density call seems to be, “how close can you go”.
Closer plantings in cherry orchards have been a noticeable trend both in Australia and overseas for a number of years now.
USA and Canada
In the western states of the USA and in western Canada, it is evident that the wide–spaced plantings that took place during the 20th century are being replaced by high or medium density plantings.
In the US the trend has been driven partly by the fact that the next generation of pickers from ‘south of the border’ are not too keen to climb and move 14-foot ladders, and the need to be more cost effective when it comes to labour costs.
The driver in Canada, which appeared to be leading the trend on that continent, was the fact that holdings were smaller and needed to improve production to maintain profitability.
Europe
Similarly in Europe, wide spaced large cherry trees have almost disappeared in favour of the high density plantings using dwarfing rootstocks.
The key drivers there were occupational health and safety issues and the need for higher production per hectare.
Turkey, the largest sweet cherry producer in the world, has been an adapter of dwarfing rootstocks with the benefit of quasi government subsidies for nursery production.
Australia
In Australia, Tatura Trellis led the way for medium to high density plantings.
In many areas the soil conditions can be dwarfing in comparison to the same cherry rootstocks grown overseas. So the results of planting any new rootstock is dependant on the soil type and growing conditions of your region.
That is why trial plantings of cherry rootstocks and the combination of the scion that is grafted onto it, is a sound idea. There are now a number of newer rootstocks that were not available in Australia in reasonable numbers until recently.
Benefits
High density plantings are a cost effective means of organizing your orchard for rain covers, protective netting, irrigation systems, fertigation or fertiliser application, and cost effective harvesting.
If you decide to go down the high density path, you will need to know what your existing growing costs per hectare happen to be. Then, if a trial block is established, a comparison can be made to check if this is the correct location for this system.
Tree management system
A final decision is the choice of tree management system that will suit your rootstock and variety combination. This can be spindle, Tatura Trellis, Bush or a mix of several.
Just make sure that you do not use a dwarfing rootstock with a very precocious heavy bearing cherry because there is no market for dwarf cherries!
For information, see the September 2012 issue of Tree Fruit
