a green geofortress against sea erosion

7/28/2019 A Green Geofortress Against Sea Erosion

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• At times of heavy downpours of southwest monsoonreceived every year it is a common experience that thesea surges into the shores especially towards thesouthern parts of the state causing severe damage to the

dwellings of the fishermen and eroding extensive areasof sand. This year even at the commencement of themonsoon the attack is very severe in places likeValiathura.

• Even the stone walls erected on the coastline are not at

all effective in preventing the violent attack of the wavesand the coconut trees on the areas are not at all havingany role in this respect, instead usually they are earlyuprooted by the advancing waves. The coconut treesnormally lack resistance against natural calamities like

drought, floods, sea erosion as well as attacks of pestsand diseases. That is the very reason why coconut treespose severe health hazards now a days facing casualtiesas well due to leaf yellowing.



• It was the very same case noticed at the time of the

Tsunami attack during 2004. While the western

Coastal areas experienced very serious damages to

the coastal areas resulting in casualties and severe

damages to the dwellings the eastern areas with

trees growing there such as Casuarina were

comparatively safe. Areas with mangrove forests onthe coastal lines were comparatively safe from the

damages. It was interesting to learn that Andaman

Nicobar islands with plenty of different extensively

grown tree species were practically undamaged andthe inhabitants were also safe from the severe

damages caused by the tsunami under the

protection of the trees.



• What is the reason for this difference ? While costal areaswithout any trees or with coconut trees are highly prone tothe attack of the trecherous sea waves at monsoon rainy

season or Tsunami waves, areas with well growndichotomous trees with strong stems and thick canopies arewell capable of successfully resisting the ravages of the sea

waves, a wonderful achievement indeed.

• Let us examine why this happens so. In Coastal areas where

no tree growth is there the waves are free to advance towardsthe shore and to erode the loose soil to any extent. There is

no force to prevent the erosion. In the case of coconut treessince it is a monocot the tree has got a single conopy withonly one terminal bud and the venation is parallel and the

roots are rather unbranched or very poorly branched wherebythe total root system is not at all capable of holding the soil at

the base firmly. It can never form an effective network of roots to hold the soil firmly intact at all. That is the veryreason why the land on sea costs with coconut trees gets

easily croded in contrast to areas with dichotomous trees.



• As against this let us see what happens in the case of

dicots. Here the tree shape itself is entirely different.

The stem though cylindrical the basal position is

thicker with buttressed roots in many having a broad

based pyramidal shape in comparison to the

cylindrical shape of the coconut tree.

•

The strong and deep tap roof broad based aboveand tapering below provides a strong anchorage to

the tree with the extensive network formed by the

branches and branchlets. The dicot tree shape is

comparable to Eiphel tower while the monocotcoconut tree shape is comparable to Pissa tower.

Definitely the former is stronger with broader base

and hence stronger foundation than the latter.



• The strong tap root combined with the laterals and

their innumerable side branches combined togetherform a close network all around the base of the tree

spread out in extensive areas thereby providing avery firm strong hold over the soil there which in no

way will yield to the waves of the sea water however

strong they may be. So the expanded broad base

combined with the firm and the strong closelyinterwoven network of roots below function as astrong fortress against the waves of sea water.

• The dicot trees planted in 3 or more alternative rows

along the sea shore will provide a strong defenseagainst the strong waves whereby the wave gets splitup and passes through the clefts between the trees

whereby they lose their strength and passes with

reduced force towards the shore.



This was significantly different from the retaining walls

constructed on shores or buildings on coastal zones

which offer a continuous surface for the heavy attack

of the tsunami waves. The attack being heavy andthe foundation being weak they can but subsidewhereas the strong tsunami waves attacking the tree

wall they get cut into pieces in between the gaps of

the trees and loose force and the waves graduallymove away through the gaps in between the trees of the subsequent rows.

• In this regard the superiorly of rubber trees over

other species of hard wood trees like jack tree, teakMahogony is very evident because its natural habitat

is the Amazon river basin and it prefers nearness to

water bodies on the banks of rivers.



• On the banks of Amazon and its tributaries the

rubber trees are seen to remain in deep water for

months together. Another most important proof

is that the seeds of the rubber tree are adapted

for water dispersal as they will float on water

surface until they land on shores where they

germinate and grow further.

• Hence a most important procedure to be adopted

in the case of prevention of sea erosion during

monsoon downpours and also during tsunamicalamities if any in future is to protect our coastal

lives using green geofortresses with rubber trees

the modern ‘Kalpa Vriksha’ of India.



Apart from the other well known attributes of the

tree to the country in a good number of ways

such as income generation to the grower and the

labourer, its efficacy in eliminating the ill effectsof global warming by aforestation and so onproviding a strong and effective defence to the

coastal zone against sea erosion during monsoon

and even at tsunami attack is a really wonderfuland exquisite achievement indeed. Therebyproving that rubber tree can act as a green

geofortress also ! The trees being planted should

be only seedlings raised from seeds and notbuddings to ensure the desired tree shape

suitable for the purpose.



TSUNAMI WAVES



DICOTS ON THE SHORE

a green geofortress against sea erosion

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