Cincturing reduces macca tree growth
From the September 2012 edition of Agriculture Today.
Cincturing has been found to effectively moderate the increase in tree height in macadamias with little difference in crop yield over a three year trial.
This new finding by NSW DPI researchers at Wollongbar identifies cincturing as a potential management strategy to improve light penetration and access in macadamia orchards.
“It is still too early to say what the long-term implications for yield are going to be – but this study definitely identifies the potential for another tree height management tool in macadamias,” said DPI research horticulturist Lisa McFadyen.
“Lower tree height is important for light penetration to the orchard floor, allowing groundcover growth and quicker access for machinery to the orchard after rain, particularly for harvesting.
“Lower tree height also improves spray effectiveness.
“However, using a mechanical hedger to ‘top’ trees substantially reduces yield.”
Ms McFadyen said cincturing or girdling is commonly used in apple growing to control tree size.
“Girdling has also been shown to reduce tree growth in citrus, pear, avocado, mango, peach and persimmon.
“Cincturing disrupts the phloem resulting in an accumulation of photosynthates above the cincture – and less root growth which is thought to reduce the supply of growth hormones from the roots to the shoots.”
The DPI trial to assess the potential of cincturing for tree size control was carried out in a planting of 12-year-old trees at the Centre for Tropical Horticulture, Alstonville.
The trunks of 849 variety trees were cinctured in late August 2008 and early September 2009.
Cincturing reduced the increment in tree height over three years by 50 per cent relative to untreated trees.
The effects of cincturing on shoot growth persisted for at least the second vegetative flush after application.
The effect increased with the number of times the trees were cinctured.
Contact Lisa McFadyen, Wollongbar, (02) 6626 1158.