Wind fire scorches trees and plants in coastal belt

Scientists of Central Plantation Crops Research Institute (CPCRI), Kasaragod, have said scorching of some trees and plants seen in the coastal belt is due to “wind fire” or “heat burst.”

Dr K B Hebbar, Head, Plant Physiology, Biochemistry and Post Harvest Technology at CPCRI said leaves of the trees were scorched during the third and fourth week of June. Owing to blowing of heavy wind, the scorching is attributed to “wind fire” or ‘heat burst.’

“It was due to high concentration of salt (salt spray) deposit on the plants all along the coast. It is a natural phenomenon, in the month of June, the commencement of monsoon starts with gusty winds and heavy rains.

“Wind brings tiny droplets of salt to the sea shore and adjoining areas. Unusually, this year during second and third week of June, there were heavy winds and little rain accompanying it compared to the corresponding period of 2014. Storms with high wind and low rainfall are especially likely to cause high salt accumulation on plants growing in close proximity to the ocean.

“Due to lack of sufficient amount of rainfall, leaves do not have an opportunity to shed the salt before it begins to affect the tissue causing browning, burning and eventually necrosis (cell or tissue death),” he added.

Salt concentration

“Ions like sodium and Chlorine enter the leaves and causes osmotic imbalance which not only dehydrates the tissue but also affect the process of photosynthesis, protein synthesis, etc.

“The degree of scorching and necrosis depends on the salt concentration. Necrosis was more in plants growing near the sea shore and declined gradually away from it.  In some trees and shrubs necrosis is seen on the windward side only while the other side is green in colour. In grasses and small plants which are sensitive to salt, the effect is seen on the whole plant,” he added.

Some plants have evolved specialised mechanism by which they exclude or compartmentalise the salt in the cell and thereby minimise the salt effect on organelles and make the plant tolerant.

The trees that are tolerant to salt are Casuarina, Acacia, Cassia, eucalyptus, etc. While coconut, citrus, guava, mango, pineapple, cashew, sapota, areca nut are moderately tolerant. Plants like banana, papaya, lime are highly sensitive to salt.  The plants in which necrosis is seen in whole foliage may die within few days, while with few green leaves it may recover back slowly.

CPCRI Director Dr P Chowdappa said it is a natural calamity and its effect could be mitigated to a large extent by planting salt tolerant wind barriers like casuarinas, acacia, and cassia as a border plant near the sea shore.

The wind carrying salt will be deposited on these plants and the main crop will be protected.

Also the salt effect can be minimised by soil amendments like application of organic manure, fresh water spray to the young seedlings to wash off the salts etc. The samples of the healthy and affected coconut and other plants have been collected for the analysis of sodium and chlorine.