Every year, during World Environment Day, there is talk of planting trees; and saplings are planted with fanfare involving both government and civil organisations with media in the tow. Planting trees is said to contribute to 16 of the 17 SDGs. The only problem of planting and forget ensures that the survival rate is very poor. So saplings planted need to be nurtured and now political leaders have started talking about it but the moot point is how much care is put to ensure the survival of the saplings planted.
Planting trees is good no doubt but the way things are going, one needs to question whether the system needs improvement. As mentioned earlier, merely planting a few lakh saplings in the valley areas will have limited advantage if the hills are not covered.
Rather than planting, stopping felling of trees will have a much greater impact but is the government doing enough to stop tree felling?
The government planned to plant 75 lakh saplings by August in the surrounding hills; a good initiative and hope it comes true. But will planting more trees arrest the Climate Change?
The answer to this is complicated and as everything on the earth is linked, only a holistic approach can be able to combat the effects of climate change.
A few decades ago, Eucalyptus was the preferred species and in one paper of this writer, when the ill effects of this species was pointed out especially roadside plantation, one senior officer who was earlier with the Environment Ministry vehemently propounded the benefits of the species; leading to very strong arguments.
Planting trees cannot be a panacea for climate change and certain principles need to be catered for maximum benefits.
Danger of introducing exotic species
The earlier tendency to bring in exotic species must be done away with as it can change the biodiversity.
Nature had nurtured specific species in specific location and any major change in the species profile can impact the region. Monoculture plantation should be discontinued and a number of indigenous species need to be planted together after a systematic study.
One may have observed that below pine tree, or Eucalyptus or even Lantana, there is hardly any undergrowth as the leaves of these species contain phytotoxin which inhibits growth of other species. Thus such species are not good species to plant.
Rain Forest are divided into layers and some authors claim there are seven, some three, some five but the most common is four layers. These are Emergent layer, high tree tops that rise above anything, the next is canopy which are made up of thick branches and leaves of taller trees, the third is the understory the layer below the canopy where short trees, shrubs and shade loving plants grow and the last is the Forest floor which are damp covered with fallen leaves fed on by fungi and other microorganisms.
Thus, a forest is a complex habitat where different species survive and thus while planting trees one need to select the most suitable species so that the artificial plantation mimics the best of nature.
Planting fast growing exotic species can be counterproductive and it is good that the craze of planting Eucalyptus and Chinese teak (Paulowmia species) which was there some time ago had died down. These are very gregarious and fast growing trees and it can literally obliterate indigenous species, besides changing the water table as they are water guzzlers. Planting gregarious exotic species can lead to extinction of native species.
The danger of introducing exotic species can be seen in the introduction of European rabbits (Oryctolagus cuniculus) in 1859 in Australia, which spread so fast that it literally destroyed a number of native species that in the 1950s the government was forced to introduce myxoma virus which causes myxomatosis a disease that only kills rabbits.
In 1996, Rabbit Haemorrhagic Disease Virus was also released which killed nearly 90 per cent of the rabbit population but the animals started developing resistance to both the viruses.
Introduction of Invasive Alien Plant Species (IAPS) have led to decline in native species which are adapted to the local environment being climate resilient and maintain ecological balance. Some well known IAPS are Lantana camara (Thirei or Nongbanlei or Namthirei), Ageratina adenophora (Catweed or Crofton weed), Mikania micrantha (Uri hingchabi), Eichhornia crassipes (Kabokang), etc which were not intentionally introduced are now very dangerous weeds in Manipur.
There are many others which were intentionally introduced like Brachiaria mutica (Para grass), Oxalis debilis (Brinam yensil), Ageratum houstonianum (khongjai napi achouba), etc and playing havoc as weeds. Thus the only alternative is to plant mixed native plant species rather than Acacia or Eucaplytus or Paulownia, etc which are exotic and can cause severe biodiversity damage.
Say no to Monoculture
As mentioned above, the tendency to plant a single species as monoculture need to be avoided and a mix of a number of species may be planted. The concerned department may work out the best combination based on the studies and literature available.
Recently, there are claims that fruit bearing trees are planted but unfortunately the varieties are of the inferior quality which has little economic value. Even local varieties of mango like heijao (big fruit), banana also heijao etc can be reproduced and planted. Some efforts put in to identify the better species and varieties will be good in the long run.
Cutting corners will only impact the environment. Yes, in plantation for economic purposes, exotic species and varieties may be introduced. Even here, the most suitable varieties need to be identified like low chilling apples, pear, etc not like the import of costly plum sapling from Netherlands which all failed about a decade ago. But exotic species must be avoided in large scale planting of 7.5 million saplings.
Many restoration ecologists have pointed out that human cannot plant our way out of climate change. Planting trees have many benefits but relying solely on it to combat climate change is a very simplistic approach.
Planting a tree may be very satisfying as trees are entrenched in our psyche and it is tangible and makes one feel good that one is contributing in the combat against climate change. Planting trees can no doubt lead to improved biodiversity, water quality and increase shade. But it can also harm native ecosystems if not properly planned. Planting cheap exotic alternative species need to be avoided.
The Cardinal Principles
The four cardinal principles which need to follow while undertaking forest initiatives can be said to be - (1) reduce forest clearing and degradation as protecting an intact forest is more efficient and ecological sound and less expensive; (2) Take tree planting as only a small part of a multidimensional environmental solutions, though increasing green cover is one of the best options to offset a portion of the anthropogenic caused greenhouse emissions; (3) Balancing social and ecological goals by acknowledging competing land uses and focus on those areas which has the potential to generate large scale benefits; and (4) Proper planning, coordination and monitoring and involving local stakeholders by settling land use conflicts.
While focussing on the ecological gaols, the need for indigenous species will override over exotic species, except in commercial plantation like orchards, etc.
Trees are but a small piece in the puzzle in the strategy to combat climate change and the most urgent need is to reduce green house gas emission that is, reducing use of fossil fuels; not a very easy option. Trees as a solution to reduce the carbon emitted through carbon sequestration is very limited though it has immense benefit in term of reducing temperature through green cover, biodiversity, etc.
The total carbon sequestered in the land ecosystems of the earth in a year is only about one third of the carbon released due to burning of fossil fuels. Besides carbon sequestration is a long slow process and if the tree is cut or died or if there is forest fire etc the carbon sequestered will be released in a jiffy. So there is always an element of risk. There is also a saturation point on carbon sequestration where a forest can no longer act as a sink where the carbon absorbed equals to the carbon released.
Man’s understandings of the complex relationship between the various parts in an ecosystem are still very limited and therefore any proposed solution can be more damaging. As per the existing knowledge the best option need to be adopted. Further tree planting can distract from other climate solutions. Riding a fuel guzzler to reach the venue of a tree plantation site is totally counterproductive, which many still undertake.
(The views expressed is personal)