Over 40 per cent of Sri Lanka’s rainforests have disappeared, and the country has lost nearly 30 per cent of its endemic species in recent decades. On Kaleidoscope last week was tropical ecologist, and agroforestry and rainforestation farming expert Prof. Friedhelm Goeltenboth, whose 25 years plus experience across Asia gave multiple angles on how Sri Lanka and the world can still retain forests and fight climate change.
Following are excerpts of the interview:
You have been working in Sri Lanka for years. What is the single most damaging thing that we are doing to our forests right now?
I have been in this country, travelling up and down for more than 20 years. Over that time, I have seen both very positive and very negative developments. The most damaging issue that I see right now is the buffer zones around protected areas are not well managed. These buffer zones are actually the key to protecting what lies within. If they are not properly managed, then, in the long run, you lose what you are trying to protect. So, for me, buffer zone management is absolutely crucial; it is the key to effective nature conservation.
Are we losing our forests because we do not know any better, or, because some people profit from the system?
I do not think that it is about not knowing better. The real issue is that nature, in itself, has no recognised economic value. A tree only contributes to the gross domestic product when it is cut down, not when it is standing. A standing tree provides so much: oxygen, water retention, habitat for pollinators – an entire range of benefits to communities. It is not just timber. I always say, a tree is not just standing plywood; it is a living organism with immense positive impact. Once you remove it, it is gone forever.
So, when logging is framed as development, the question is, who is actually developing?
Often, the profits from logging leave the country and are not reinvested locally. That is a major problem. Historically, development and agriculture have involved clearing forests. But, if the value taken from nature is not reinvested locally, then, ultimately, you lose.
This is where rainforestation farming comes in. It is a model for sustainable agricultural development that works with nature rather than against it. Instead of moving from biodiversity to monoculture, it preserves multiple options for livelihoods – medicinal plants, food crops, timber, and more.
In contrast, monocultures like palm oil plantations offer only one product, often for export, while leaving behind degraded land. Over time, you end up with what I call ‘green deserts’ – landscapes with very little ecological value.
Rainforestation farming aims to combine three things: improving livelihoods, protecting biodiversity, and preserving landscapes. The closer that production is to the natural environment, the more sustainable it becomes.
Farmers are often indebted and struggling. Why would they trust rainforestation farming?
Farmers are naturally conservative – they follow what has worked for generations. So, why should they believe something new? My answer is: they should not believe it; they should see it. We do not just give advice or preach. We establish model farms in partnership with local farmers – real, working examples. Farmers can observe them, learn from them, and adapt them.
A key principle that we insist on is the use of indigenous plants only – no exotic species – because, native plants are adapted to local conditions through evolution, making them far more sustainable. So, it is not about theory; it is about showing a practical, working system that farmers can trust because they can see it succeed.
Sri Lanka has planted trees, but, still lost forests. Where have we gone wrong?
A: Yes, that is true. From what I have seen, Forest Conservation Departments often prioritise fast-growing, timber-producing species, many of which are non-native. If this continues, we risk losing not just biodiversity, but also our landscape identity. You could end up with ecosystems that resemble South America rather than Sri Lanka.
have seen this in countries like Vietnam, where vast areas are covered with acacia plantations. Initially, it seems productive, but, over time, the biodiversity declines. Pollinators disappear because they cannot survive on non-native plants. So, the biggest mistake has been prioritising short-term gains over ecological sustainability.
Population growth – is that the real problem, or just an excuse for poor policy?
Population growth does have an impact, it is often used as an excuse for inaction. Farmers are frequently pushed into cash crop systems instead of being supported to sustain themselves.
For example, some farmers grow rice that is too expensive for them to consume – it is instead produced for high-end markets. Traditionally, farmers had larger families because they needed labour. But today, when they have access to better opportunities, they naturally choose smaller families. They are not unaware – they understand sustainability better than most. The key is to support farmers in maintaining self-sufficiency – producing their own food first and then selling the surplus. Not the other way around.
How quickly does rainforestation farming generate income for farmers?
Income depends on the specific situation, but, the model is designed to provide returns at different stages. We move away from monoculture to a diverse system that includes short-term, medium-term and long-term crops. Short-term income comes from vegetables and quick-yield crops. Medium-term and long-term income comes from trees and perennial crops. Under tree cover, farmers can grow shade-tolerant crops like spices, which also generate income.
There is also a guiding principle often described as a “30-30-30-10” model: land should be balanced between carbohydrates, proteins, other nutrients and 10 per cent for housing and infrastructure. If this balance is achieved, the farmer is secure. Without it, farmers become dependent on external markets and earn very little.
Have any countries in South Asia adopted rainforestation farming?
The concept was developed in the 1990s through collaboration between universities in Germany and the Philippines. In 2004, the Philippines officially adopted rainforestation farming as part of the Government policy, particularly for forestry practices. Since then, the model has been expanded and tested in countries like Indonesia, the Philippines and now Sri Lanka.
What are the biggest challenges in implementing this model?
The biggest challenge is bureaucracy. In many countries, Government departments operate in silos rather than working together. One department may not even be aware of what another is doing. This lack of coordination makes implementation difficult. It is a global issue, not just a Sri Lankan one.
Can farmers who practice slash-and-burn cultivation transition to rainforestation farming?
Yes, they can. We have seen this in the Philippines. Slash-and-burn agriculture was sustainable in the past when populations were low and land had time to recover. But today, with shorter cycles, soil degradation happens much faster. Farmers are often forced to move every few years because the land becomes unproductive. This leads to further environmental damage and financial instability.
Farmers already know that practices like clear-felling are harmful, but, they often have no alternatives. If you provide them with a viable model and access to support, such as microcredit to avoid exploitation by middlemen, they are very quick to adopt better practices.
What are the three priorities that Sri Lanka should focus on to make rainforestation farming successful?
First, rediscover and use existing local knowledge. Sri Lanka already has strong traditional systems. For example, the tank irrigation system, which is an excellent model of sustainable water management. Second, integrate modern approaches with these traditional systems. Combining innovation with proven local practices can create powerful solutions. Third, ensure proper implementation and connectivity. For example, maintaining and linking irrigation systems effectively. If systems like the tank network were fully functional, even the recent flooding could have been mitigated.
So, the way forward is not just importing new ideas but combining them with the wisdom that already exists locally.
The writer is the host, director, and co-producer of the weekly digital programme ‘Kaleidoscope with Savithri Rodrigo’ which can be viewed on YouTube, Facebook, Instagram, and LinkedIn. She has over three decades of experience in print, electronic, and social media
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The views and opinions expressed in this column are those of the author, and do not necessarily reflect those of this publication
(Scan the quick response [QR] code or visit the channel ‘Kaleidoscope with Savithri Rodrigo’ on YouTube for the full programme of 30 April 2026.)