Holding the Ground: Why Sri Lanka’s Earth Gave Way and How to Heal It
- Christine R.
- Jan 19
- 4 min read
In the steep slopes of Udadumbara, on the fringes of the Knuckles Range, nature recently demonstrated its overwhelming power. But what appears to be an unavoidable natural disaster is, upon closer inspection, a complex interplay of geology, shifting climate systems, and human land management.
The weight of fertile earth
As a landscape ecology engineer, I view the lush green mountains of Sri Lanka through a specific lens. The island is blessed with deep, fertile soils, but on steep gradients, this very depth becomes a liability.
Located in the central highlands, Udadumbaras landscape is shaped by high-grade metamorphic rocks. Deep within the Earth’s crust, these formations were once "re-cooked" under intense heat and pressure, transforming minerals into shimmering crystals and striped bands.
Yet, while you might catch a glimpse of these patterns in a fresh cliff face, the reality on the ground is often different. In the tropics, chemical weathering is relentless. Instead of solid rock, you frequently encounter formations that are heavily fractured and visibly cracked, making the mountainside far more unstable than it appears.
From rock to heavy clay
This intense weathering process is what eventually turns solid stone into the earth beneath our feet. Over time, the rock breaks down into a thick, often reddish layer of loose material and soil. What makes this layer so dangerous in Sri Lanka is its high concentration of clay minerals.
These clays have a treacherous property: they act like a massive sponge, capable of holding enormous amounts of water. As they saturate, the total weight of the hillside increases dramatically, transforming the once-stable ground into a heavy, mobile mass waiting for a trigger.
The physics of failure: A landscape saturated
While local rain gauge data for Udadumbara’s remote peaks is difficult to obtain, the regional numbers tell a terrifying story. In late November, nearby Jaffna staggering 520 mm of rain were recorded in just one week, with nearly 390 mm falling in a single 24-hour window.
The soil mechanics of such an event are unforgiving. As the heavy clay layer saturates, the pore water pressure rises so high that the water trapped between the soil and the underlying bedrock begins to act as a lubricant. Gravity inevitably wins as entire hillsides, often carrying fractured granite blocks, lose their internal grip and descend as fatal mudslides.
Why the forest is the best engineer
The difference between a stable slope and a catastrophe often lies in the vegetation. In
Udadumbara, the evidence was clear: the most devastating landslides occurred where pepper monocultures grew or tea plantations dominated. These systems lack the complex, deep-reaching root architecture needed to anchor the soil to the bedrock.
A healthy, biodiverse forest is a great example of natural slope stabilization. Its roots weave through different soil layers, locking them together like living rebar. Deep-rooting canopy species such as Hora (Dipterocarpus zeylanicus) and Na (Mesua ferrea) anchor steep slopes, helping to keep the soil firmly in place.
The Kandyan Forest Gardens take this principle a step further: by replacing monocultures with a mix of spices and fruit-bearing trees such as Jackfruit (Artocarpus heterophyllus) and Mee (Madhuca longifolia), farmers gain both soil stability and a sustainable livelihood. This approach turns fragile slopes into resilient agroforestry systems, reducing landslide risk while diversifying farmers’ income beyond a single crop.
Shifting climate dynamics
We are witnessing the dissolution of traditional weather patterns, as the South-West Monsoon this year extended well into December and began to overlap with the North-East Monsoon. These shifts are increasingly driven by rising ocean temperatures, which are altering evaporation and rainfall cycles across the region.
What once appeared as abstract climate projections is now unfolding on the ground, with these disrupted systems already translating into human loss. In Sri Lanka alone, more than 350 lives have been lost to extreme weather conditions this season; a wake-up call that cannot go unheard.
Our path: Healing through resilience
The government is restricting reconstruction in high-risk zones, recognizing that building in these areas is no longer sustainable under current climate projections.
The Forest Healing Foundation focuses on prevention by healing the land before it slides. For over 8 years, we have been dedicated to local reforestation. Our expertise allows us to select specific native species that do more than just sequester carbon since they provide active slope stabilization. We are rooted in the community and know that environmental protection only works when it supports the people who live there. Currently we are working on a resilience project to extend into Sri Lankas landscape. Our goal is to transform vulnerable hillsides into resilient ecosystems, ensuring that the land remains a source of life and livelihood, rather than a threat.
How you can help
We are working on two fronts: immediate relief for those who lost everything & long-term prevention through reforestation.
Emergency Aid: Support our immediate relief efforts for families displaced by the recent
landslides in Udadumbara and surrounding areas via this link:
Long-term Healing: Help us plant the "bio-engineers" of tomorrow by donating to the Forest
Healing Foundation through this link:
Together, we can turn vulnerable slopes back into resilient ecosystems.
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