Tamil Nadu

‘Planting of exotics harmful to Nilgiris’


Conservationists point out exercise will have a huge impact on soil chemistry, wildlife in the region

A Coonoor-based trust proposes to plant more than 10,000 trees in the Nilgiris. But there is a problem: almost all of them are exotic flora — from avenue trees such as jacaranda and podocarpus, to pine and bottlebrush.

It highlights the growing trend among NGOs, social service groups and even celebrities looking to contribute towards the rejuvenation of the green cover in the Nilgiris.

Conservationists say that though the intention is commendable, the ill-thought out mass plantation drive, some conducted with the assistance of the district administration, will be harmful to the environment in the long term.

Dr. Tarun Chhabra, an environmentalist working on habitat restoration Nilgiris, said exotic trees such as pine, podocarpus and cypress trees have a huge impact on soil chemistry on the ground where they are planted, preventing native grass, plants and herbs from taking root underneath the canopy.

It has a knock-on effect on wildlife, resulting in their vacating the areas, he says. “Only native grasses should be grown in what were previously grasslands, or Shola trees should be grown where they existed previously,” said Mr. Chhabra.

N. Mohanraj, a Nilgiris-based ecologist, said growing exotic trees in the Nilgiris is counterproductive to conservation and ensuring biodiversity.

When exotics take root in a particular area, they increase the water demand in that region, impacting not just the Nilgiris but other districts further downstream that rely on rivers emanating from the hills.

Need for policy

The government should come up with a policy that stipulates that only native flora should be planted in public spaces in the Nilgiris because of its ecological significance and its unique biodiversity, say conservationists.

One of the justifications offered for the introduction of exotic trees is that they lead to better soil stability of the slopes on which they are planted. However, conservationists contradict this assertion. “The argument that exotics lead to soil stability is also fallacious, as the roots of these trees are very shallow, and the trees can get uprooted by high velocity winds and heavy rain, which characterise the monsoons in the Nilgiris,” said Mr. Mohanraj.

Nilgiris Collector J. Innocent Divya said the district administration had recommended to groups conducting plantation drives that only native species should be planted in the district.

“However, one of the issues they face is that the Forest Department has only enough native trees to afforest their reserve forests, so they do not give out any saplings to private individuals,” said Ms. Divya.

She said she had written to the Chief Conservator of Forests requesting a shift in policy that will allow for the Forest Department to supply native tree saplings to individuals and groups interested in afforestation.

Best practices

There needs to be a better understanding of the best ecological restoration practices that can be implemented when working in a landscape as crucial and sensitive as the Nilgiris, experts argue, stating that the Forest department too needs to rework its forest regeneration strategies.

Large-scale planting of exotics in ecologically-sensitive areas must be discouraged, said a senior Forest Department official.

“Shola tree species require a lot of maintenance post-planting to ensure their survival. Maintaining a Shola nursery is indeed very difficult as the trees are very slow in growing,” he said.

The priority of the Forest department is ensuring supply for their afforestation efforts in areas where exotics and invasive trees are removed,” he admitted.

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Printable version | Jan 25, 2020 1:55:51 PM | https://www.thehindu.com/news/national/tamil-nadu/planting-of-exotics-harmful-to-nilgiris/article30552570.ece

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