I grew up with a big garden. The growing season in Sweden is short, but my mother was passionate about planting flowers and testing new varieties; we also had lots of fruits and berries, and as a child, I loved to pick them and eat them – and to earn pocket money doing yard work.

I went on to become a geographer, and after the 2004 tsunami, I found myself in Sri Lanka, studying the storm’s effects on vegetation. During my visit, I discovered the local approach to “homegardens”: small, densely planted spaces with flowers, food crops and trees in multiple layers, creating complete mini-ecosystems. I was half a world away from my mother’s garden, yet the beauty and tranquility of the gardens, and the self-sufficiency they provide, took me back to my childhood.

The colours in Sri Lankan homegardens are rich and bright, and the hot, heavy air is filled with sweet scents, sometimes spiced with the aromas of meals being cooked in the families’ kitchens. The lush vegetation attracts birds, butterflies, lizards and monkeys, and if you close your eyes, especially in wet-region gardens, the wildlife sounds could make you think you’re in the rainforest.

Yet these gardens are not grown for the aesthetics alone. They provide fresh, organic, nutrient-rich food – a huge benefit to the families – and fuelwood as well. The gardens are also extraordinary in terms of biodiversity: though most include at least a few coconut, mango, banana and papaya trees, I’ve found all sorts of other plant and tree species in the gardens of rich and poor people alike. That’s part of the thrill of visiting Sri Lankan homegardens: you never know what flora or fauna you may encounter.

From a research perspective, I see these homegardens as prime examples of multifunctional landscapes: spaces that combine agriculture, forestry and natural ecosystems. The “landscape approach” is gaining prominence as a more holistic – and effective – approach to food security, reforestation and overall sustainability than the single-sector interventions that have long prevailed in the development world. I strongly support that approach, but if it is to succeed, we need to start by realizing that people in Sri Lanka and many other countries have long built multifunctional landscapes. Yet modern agriculture, forestry and development practices have driven a shift to often-unsustainable, single-use landscapes.

My research focuses on the role of land-use change and forestry in climate change mitigation and adaptation, with an emphasis on conservation, sustainable management of forests, enhancement of forest carbon stocks, and reduction of emissions from deforestation and land degradation. In that context, I have explored ways for Sri Lanka to realize its climate change mitigation and adaptation potential in the land use and forestry sector, including potential REDD+ activities.

My latest study, which I will be presenting at the World Congress on Agroforestry, examines the role that homegardens in meeting Sri Lanka’s climate-related goals – and, in turn, how climate programmes such as REDD+ could encourage more families to grow gardens, or expand existing gardens. To gauge homegardens’ carbon storage capacity, we visited 45 dry-zone homegardens in two villages in Moneragala district, in southeastern Sri Lanka, and documented the types and sizes of trees on each property – a total of 4,278 trees of 73 species. We calculated the above-ground biomass stock and found it averaged 13 Mg carbon (C) ha^-1 – but with huge variations: an average of 26 Mg C ha-¹ in the 11 small gardens we sampled (under 0.2 ha), versus 8 Mg C ha^-1 in the seven gardens over 1 ha that we sampled (mid-size gardens’ carbon stocks were similar to those of large ones).

Our analysis provides two key insights: First of all, homegardens clearly have great capacity for carbon storage and could make good candidates for Sri Lanka’s newly commenced UN-REDD National Programme. Second, tree density and species diversity make a big difference; the small gardens had much higher carbon storage per hectare than large ones because they were far more densely planted.

In our study area in particular, conditions may be particularly suitable for increasing homegardens. Large-scale infrastructure developments and investments in the area are driving up population density, increasing the need for efficient food production. And a water storage tank is being built that could support irrigation as needed, making it easier for farmers and homegardeners to plant more trees and perennials of different varieties, enhancing the carbon density and biodiversity of the land while also improving food security.

More broadly, Sri Lanka may also want to consider promoting homegarden establishment on lands adjoining the remaining natural forests, creating buffers in areas that are experiencing pressure from increasing populations. For best outcomes at the local level, schemes such as REDD+ could be linked to existing or emerging development programmes, highlighting food security and market integration – both of which are likely to be greater priorities for farmers than climate change mitigation.

Eskil Mattsson is a post-doctoral fellow at Chalmers University of Technology in Gothenburg, Sweden, and a theme leader of Focali, a Swedish research network focused on forests, climate and livelihoods. He will present his work at a WCA session on tropical homegardens on 10 February.

Photo: Example of a wet-region homegarden

Blogpost and photo by Eskil Mattsson (Stockholm, Sweden) – eskil.mattsson(at)chalmers.se