Countries
in tropical regions are prone to cyclones which cause significant damage to
crops, especially tree crops such as native fruits (bananas) and exotic fruits.
The exotic tropical fruits include lychee, rambutan, durian, mangosteen,
jackfruit, macadamia nuts, and avocado. Trees that take years to produce a crop
can be devastated by a cyclone in a matter of minutes.
Farmers
in cyclone prone areas of northern Australia have experimented with disaster
management for their crops, in order to reduce damage, and maintain
productivity during the roughest of weather. For example, two disastrous
cyclones hit the region within a five-year period, leading to
farmers leaving the land permanently. As a result Australia’s Rural Industries Research and Development
Corporation (RIRDC) commissioned two projects to identify and address
cyclone-related issues for primary producers (Rural Diversity, RIRDC, Issue No.
14, Summer 2014).
One
of the major lessons learned in the first project, Lessons Learned from
Cyclones (2011), was that trees which were trellised suffered little damage during a cyclone, whereas untrellised trees were severely
damaged. The second project, Improving the Capacity of Primary Industries to
Withstand Cyclonic Winds (2012 and ongoing), is investigating the use of trellises and tree-support mechanisms.
Trellised
trees had been used in southern parts of Australia in temperate climate
orchards for apple, plum, cherry, and pear trees. Some farmers in northern
Australian adopted a similar approach for their tropical fruit orchards,
especially after the first cyclone of March 2006 (Cyclone Larry). So by the
time the second cyclone struck (Cyclone Yasi) in February 2011, the farmers who
has used the trellis system noted minimal damage to their trees.
The
conventional “top heavy” untrellised trees were uprooted and destroyed. The
trees using the Open Tatura Trellis system fared significantly better. The
trellis system is two rows of trees, separated by approximately 50 centimetres,
planted on a diamond-shaped structure. The trees are trained to grow in a
V-shape with a 22.5 to 30 degree angle to vertical. Each row consists of two
end frames, intermediate frames, high tensile wires, and anchors.
The
difference between the Tatura and Open Tatura trellis system is that the trees
alternative left and right in the Open Tatura method. It is called Open because
of the 50 cm spacing between trees.
The
Tatura and Open Tatura trellis system is known for its high productivity - the
V-shape maximizes light interception and the space allows for greater sunlight
distribution. The V-shape is also more efficient for pruning, disease control,
and fruit picking due to greater access to the branches. It is also known to
mitigate turbulent winds and overhead air streams due to studies in New Zealand
and America.
Farmers
Peter and Alison Salleras lost their crop in Cyclone Larry, but had trellised
their trees before Cyclone Yasi struck. Yasi had winds of 320 kilometres per
hour for more than 6 hours, and although the trellised trees lost a
considerable amount of fruit, the trees remained intact.
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