MARCH 1999 NEWSLETTER

POST CYCLONE RONA - Report on damage to our farm

Our first newsletter tries to assess the damage we suffered from Cyclone Rona. Being in South West Tasmania on holiday at the time, we had 2 weeks to get used to the idea before we actually arrived home.

Friends from Cairns had spent a weekend at the farm after the cyclone clearing the debris from the driveways so that the shock was not so bad when we drove in.

So here is our assessment of the damage.

SUMMARY

Buildings, machinery and stock have suffered no damage. The orchard shows extensive superficial damage but the long term economic future is unaffected. Major crops of Mangosteen (250 trees) and Salak (1200plants) have suffered little while other species planted to lift diversity and provide shade such as bananas and legumes have been decimated.

OBSERVATIONS

Gross physical damage to trees is largely confined to 3 bands running through the block.

One band runs parallel to the driveway through the food forest over the house and through to the back section around the chookhouse. Trees damaged in this band, to near ground level include two of the large Santol, Soursop, Fijian Longan, Icecream Bean, two Marang, two Rollinia, Rambutan, as well as 5 Glyricidia. Several other trees are leaning or have lost upper branches and may recover. These include Marang, Breadfruit, Canistel and Black Sapote.

The second damage band runs from the orchard entrance straight through the centre of the orchard in a strip around 30 meters wide.

The third band also runs through the orchard, coming in from the south west corner, running east along the fence line for 100m before turning in to the Rambai and Soursop.

DETAILS OF THE DAMAGE

The entrance frame of 12 coconuts planted in 1988 has been flattened. In their falling, they have also taken out several Icecream Bean, and broken in half two Mangosteens.

All mature or near mature sugar bananas were on the ground. Total loss of around 50 formed bunches and another 100 which would have formed over the next 4 months

Eight (of 18) Breadfruit have been pruned from 10m high down to around 3m, but none have been killed and I believe that regrowth will be rapid.

Two Black Sapote (of 9) have been uprooted, and damaged beyond repair. Others show no damage apart from loss of crop (due for picking in April).

Most of our Durian were within this band. Six have been broken off at ground level, 6 have lost at least half of their timber, 8 are undamaged except for wind burn and leaf drop.

Ten (of 24) Abiu have been broken off at ground level or damaged beyond repair.

One (of 6) Mamey Sapote screwed out of the ground. Others are undamaged and still hold immature fruit.

Six (of 22) Rambutan are bent to the ground. Two of these have been pruned to 2 meters and staked up, the others are damaged beyond recovery.

Three of 5 Rollinia torn out of the ground.

Six of 15 Soursop bent to ground level. These have been pruned to 2 m and staked up.

Of 14 Rambai most have been pushed flat. They have been staked and pruned.

The largest of 4 Avocado was pushed flat.

Jakfruit showed little damage. Only where weak from Pink’s disease or hit by another tree, usually coconut were they down.

Mangosteen, were only damaged by being hit by falling trees, usually coconuts or Jakfruit. Two were snapped in half. Four had several branches snapped. Twenty or so were leaning to 45 degrees or so and have been staked after being bent straight. Hopefully they will survive the disturbance.

Mature Glyricidia ( a tropical legume shade tree)also showed little damage. They had all been pruned in the previous season and the new growth was very flexible. Areas sheltered by mature Glyricidia showed little damage beneath. Juvenile Glyricidia were down.

Salaks were basically undamaged although all are leaning. Maintenance will be difficult for six months or so until they grow upright. Many were buried under debris for up to one month before being uncovered.

CONCLUSIONS

Coconut is a poor choice for a shelter belt. If they break, the whole plant goes causing much collateral damage due to the wide head. Glyricidia works very well for shade and wind shelter if coppiced. Aim for big trunks and long thin branches. Breadfruit may work well in spite of being so weak. No tress were broken low down, all are reshooting. Fiji Longan may also be successful in a similar way, but my sample size is too small. Mangosteen and Salak were excellent choices for commercial crops in cyclone areas.

Softwooded species such as Santol, Rambai and Durian are easily damaged but probably reshoot quickly. Need to watch to see how long these trees take to bearing fruit again.

The ribbons of damage obvious on our farm are not so obvious in the forest or on other farms. These ribbons run essentially east – west, meaning that rows of trees planted north – south are more likely to go down than trees in rows planted east – west. This was also noticeable on Grays property after Cyclone Joy.

OBSERVATIONS FROM OTHER PROPERTIES

Small hardwood fruit trees such as Jaboticaba and Grumichama broken of at ground level on Masons and Grays. Damage to vase shaped Durian seems more severe than damage to christmas tree shape. Mature Mangosteen on Gray’s lower block to about 5m height left undamaged although forest on both sides showed extensive damage. Large Star Apples on Kirchners were extensively damaged although the few on our block were untouched. Ours are spindly with little lateral growth while Kirchners are spreading with round canopies at about 10 m high. These were pushed over or had larger branches broken off.

IN THE END

We are now putting all our time into clearing up the farm so that it doesn't look too disgusting to walk through with fruit tasters. We have had more than 1000mm in 4 days in the middle week of March  and the orchard is a mudbath - the ducks love it

Alison and Digby