The sooner you can attend to fallen fruit and nut trees after a cyclone, the better their chances of surviving. You can either try to reset the tree (stand it up again) or prune it and encourage it to reshoot.
In general, it is best to reset only smaller trees, since large trees will be weakened and may fall again. Try to reset trees while the soil is still wet.
For most trees that reshoot readily, consider:
- stumping the tree about 30cm above the graft (if grafted) or 1m above the ground if not grafted
- staking the stump to prevent further movement
- pruning the exposed roots and covering them with river sand or the surrounding soil and mulch heavily
- painting the upper side and end of the stump with a 1:4:20 mix of water-based, white acrylic paint, micro fine lime and water (i.e. 1L paint, 4kg lime and 20L water) to prevent sunburn.
It is very difficult to replant trees that have been completely uprooted. Unless they are heavily pruned, replanted and staked within 24 hours following the cyclone, they will probably die.
Partially uprooted trees
Partially uprooted trees (where 10-50% of the roots on one side of the tree are exposed) or trees on a severe lean, or flat on the ground, where roots may be damaged but remain underground, should be straightened while the soil is wet. After straightening, the trees should be braced. Keep braces in place for at least 2 years.
Make sure all jagged and irregular root breaks are cut, smoothed and painted with a 1:1:1 mix of acrylic paint, water, and fungicide (e.g. copper hydroxide) mix. Cover any exposed roots with soil and mulch. Keep the tree well-watered.
Prune damaged trees just enough to balance root losses. Cut out broken, diseased and malformed branches to give the tree a desirable shape. Apply a 1:4:20 mix of water-based, white acrylic paint, micro fine lime, and water to exposed branches, stems and trunks to prevent sunburn. Small amounts of fertiliser may help stimulate growth.
Young trees (less than 2-3 years old) may be reset after you prune exposed roots and remove soil on the uprooted side before lifting. Use this to cover any exposed roots. Reset the trees while the soil is still wet. Apply a 1:4:20 mix of water-based, white acrylic paint, micro fine lime, and water to prevent sunburn. Stop lifting the tree if you hear cracking due to roots snapping on the downwind side. Stake the lifted or partially lifted tree to minimise further movement from wind. You should remove up to half the canopy to compensate for root loss.
Older trees (more than 5 years old) are less likely to be easily reset without causing further severe root damage on the downwind side, therefore follow the guidelines for fallen trees. Some success has been achieved resetting older mangosteen trees, but this is the exception.
A tree might still die after being reset if there is severe root damage or fungal attack that you can't see.
If you remove dead trees, it's best to remove the stumps and roots as well because they can harbour fungal diseases which can infect healthy trees. Leave about 1.2m of stump standing as removal will be cheaper and easier if you can pull, rather than dig, stumps out.