The Kandyan forest garden system is unique to the Kandy massif in mid elevation of the wet zone of Sri Lanka. It has been a traditional way of family farming near the domicile since ancient times. During the evolution of this farming system, useful trees, herbaceous shrubs, vines, and animals were identified, protected, and managed while undesirable tree species were eliminated.
Eventually, superior foreign plant species were obtained and incorporated into the gardens. This process of forest garden diversification and development has continued, not only through deliberate additions to the existing biological mix, but also in the establishment of new gardens supporting new generations.
A forest garden can be defined as a family farming system initiated, developed, and sustained in the vicinity of the domicile. This garden supplies most of the family’s basic resource needs from a small parcel of land comprising a mix of highly diverse tree, herbaceous shrub, and vine species. Kandyan forest gardens have attained a higher level of development and botanic complexity than anywhere else in the country.
Kandyan forest gardens occur at elevations ranging from about 200 to 800 metres above mean sea level in high rainfall areas of mid-altitude hills of Western and Northern escarpments of the central mountain massif in Sri Lanka. They provide provisioning, supporting, regulating and cultural services to the farming communities.
For example, some provisioning services include fruits, spices and condiments, vegetable, edible root and tubers, palm nuts and associated products such as treacle and toddy, beverages, animal products, medicine, flowers, firewood, and timber. The high density of trees creates a favorable microclimate for living under tropical conditions and builds a very high resilience to economic and environmental shocks.
Rapid population expansion and thereby fragmentation of forest gardens in this farming community has adversely affected these services at the household level. This social fragmentation of gardens emphasises the need to direct national attention towards sustaining and regenerating this heritable agroecosystem.
Most previous review studies have focused mainly on the botanic complexity of the garden system. Factors such as social fragmentation of communities, accelerated land degradation by soil erosion, loss of soil productivity, crop damages from small wild animals and extinction of domestic animals have not been adequately researched, discussed, or addressed. Hence, this article, written in consultation with a Senior Land Use Planner in Canada and a Senior Agronomist from Sri Lanka, is intended to make the public aware of the need for conserving and upgrading this agrarian heritage for the benefit of generations to come. It is also intended to educate the Kandyan forest garden communities on ways of regenerating this agroforestry system to enhance productivity and economic benefits from this nature-friendly farming system.
Soils of the gardens
The major soils supporting the Kandyan forest gardens include Red-Yellow Podzolic, Reddish Brown Latosolic, and Immature Brown Loam soils.
The Red-Yellow Podzolic soils occur in areas such as Awissawella, Ratnapura, Openayake, Galigamuwa, Pallegoda, Weddagala, Giragama and Nawalapitiya. The characteristic strong brown to yellowish-brown makes them easily recognisable. They are best observed in tea plantations in Giragama village near Pilimathalawa.
The Reddish Brown Latosolic soils are found in areas such as Matale, Kandy, Ukuwela, Gelioya, Rambukkana and Mawanella. These soils have a characteristic reddish-brown to brown and are easily recognised in excavation sites in the Matale municipal area.
The Immature Brown Loam soils are best expressed in areas such as Akurana, Geli Oya, Pilimathalawa, Kadugannawa, Galagedara and Mawanella. The characteristic dark brown to dark grey-brown makes them easily recognisable. They can be observed along either side of the A-10 road near the Galagedara Police Station in Kandy.
The productivity of these forest garden soils has declined due to accelerated soil erosion, moisture depletion and loss of soil fertility. Adoption of appropriate soil and water conservation measures, re-introduction of domestic animals, production, and application of compost to the land would enhance garden productivity.
Plant diversity
The Kandyan forest garden system consists of tree, herbaceous shrub and vine species. With respect to community use, it includes fruit crops, spice and condiment species, vegetable crops, root and tuber crops, palm trees, beverage crops, medicinal plants, ornamental species, timber species and other useful plants.
Fruit crops
Nearly 100 fruit crops occur in the Kandyan forest garden system. The more common crops include avocado, banana, durian, Jak fruit, mango, mangosteen, mandareen, rambutan and papaya. However, maintaining all of these fruit crop species plays a significant role in in-situ conservation of genetic resources for future use.
Fruit consumption in the country remains far below the actual requirement for a healthy life. Hence, enhancing fruit crop cultivation within the forest garden system and marketing products to appropriate consumer destinations in the country would help increase daily fruit consumption of the nation.
Spices and condiments
The major crops used as spices, condiments and other food additives include clove, nutmeg, cardamom, cinnamon, goraka, tamarind, ginger, turmeric, pepper, green chilli, hot chilli, curry leaves, rampe, sera and vanilla. These crops are grown mainly for family consumption. Excess produce from crops such as clove, nutmeg, goraka, tamarind, ginger, turmeric, and pepper provide an additional income.
Most of these spices are also used for indigenous medicines and first aid treatments. Adoption of newly developed land and crop management technologies such as establishment of individual platforms for soil and water conservation in tree crops, frequent manure application, timely pruning and training of plant canopy and use of scientific post-harvest operations would help enhance economic returns from these crops.
Vegetables
Nearly 30 vegetable crops are widely grown in market gardens in nearby areas but very few occur in forest gardens. This is due to the adverse shading effects on herbaceous vegetables under the canopy of tree crops in the forest garden system.
The few vegetables commonly grown include crops such as jak fruit, bread fruit, wing bean, yard long bean, green eggplant, thibbotu and leafy vegetable such as kathurumurunga and spinach. Growing herbaceous vegetables in pots in areas which receive adequate sunlight and adoption of “vertical-pot-farming” technology is recommended for enhancing vegetable production for household consumption.
Root and tuber crops
Among root and tuber crop species grown in the forest garden system, four crops: cassava, sweet potato, large leaved yam and dioscorea are commonly grown for family consumption. Enhancing the cultivation of these crops, would be an appropriate food production strategy as these crops have a high resilience to adverse climatic changes such as the erratic nature of rains.
Palm trees
The Kandyan forest garden system includes a few palm tree species such as coconut, king coconut, areca nut and toddy palm. Some uses of these crops include coconut kernel for household food preparation and oil extraction.
King coconut is consumed as a fresh drink, arecanut for chewing with betel, toddy palm for preparation of treacle and toddy.
The toddy consumption has been limited to elderly male family members. However, female members are very actively involved in preparation of treacle as a cottage industry which could use a helping hand to expand this micro enterprise.
Beverage crops
The major beverage crops include tea, coffee, and cocoa. Tea is available as some forest gardens have been developed on marginal tea lands. Some uses of these beverage crops include preparation of hot beverage from coffee powder for domestic consumption as well as selling the excess coffee, harvested green leaves of tea and cocoa seed for income.
Medicinal plants
More common medicinal plants which grow in forest gardens include akkapana, beli, endaru, hathawariya, komarika, murunga, pavatta, polpala and wadakaha. These plants are widely used in indigenous medicines and first aid treatments.
Ornamental crops
Many species of ornamental crops are also grown in the forest garden system. Species such as agloanema, anthuriums, begonia, bougainvillea, caladium, cane palm, cannas, carnation, cordyline, croton, dahlia, dieffenbachia, dracaena, ferns, fittonia, gerbera, hibiscus, jasmine, livistona, maranta, monstera, orchids, peperomia, roses, rhapis and spathiphyllumare widely maintained. Some uses of these crops include maintaining natural beauty of the garden, harvesting cut flowers for indoor decorations, and use in religious activities.
In some forest gardens, ornamental crops such as anthuriums and jasmine are maintained as a cottage industry for income.
Timber
Among the timber plants, species which occur commonly in forest gardens include ginisapu, halmilla, hawarinuga, ketakela, lunimidella, mahogany, pihimbiya and teak. These species are grown, harvested, and used for indoor repairs to the domicile and manufacture of furniture for domestic uses and sold for timber value in case of financial emergencies. The canopy of plants is periodically lopped out and hardwood is used as firewood for domestic cooking.
Garden canopy structure
The general botanic structure of Kandyan forest gardens is depicted as a multistory plant canopy system. Each canopy level consists of some combinations of plant species. Plants such as coconut, jakfruit and durian represent the upper canopy level; nutmeg, clove, mango, papaw, avocado, mangosteen, breadfruit, rambutan, citrus and papaya occupy the middle level; banana, cocoa, passion fruit, betel vine and vanilla represent the lower level. Ginger, turmeric, herbaceous vegetables, and yam occupy the ground level.
Domestic animals
Since very little sunlight penetrates the Kandyan forest garden canopy, it is usually not possible to grow grass and fodder crops for a large herd of domestic animals. However, a few free-range chickens for eggs, perhaps, a cow for milk, a few pigs, depending on the culture and rarely stall-fed goats, are commonly kept.
Animal feed consists of tree canopy periodically lopped out, daily kitchen refuses, and grasses and fodder collected from common property land resources such as roadsides and other public lands.
This domestic animal component plays a significant role in the daily provision of protein rich foods such as milk and egg for garden families.
In cases of financial emergencies, income can be supplemented by selling an animal. Some forest garden farmers also maintain bee colonies for harvesting honey. Bees also contribute to the pollination of local flowering plants.
Fragmentation of gardens
The Kandyan forest gardens have been subject to social fragmentation resulting from expansion of village populations and construction of separate houses for new families. This reduces land availability for growing crops.
Therefore, it is suggested to shift from large canopy crop varieties to dwarf type varieties for crops such as mango, guava, banana, amberella, durian, nutmeg, coffee, toddy palm and coconut in fragmented gardens.
Soil and water conservation
Soils of Kandyan forest gardens which occur in newly fragmented lands with sloping terrain require conservation of the soil resource base to sustain system productivity. Since these gardens receive water mainly from rains and the thick forest reserves on the crests of landscapes receive diminished water due to rapid runoff of rain fall, it is important to conserve water within the garden system.
Structures such as lock and spill drains, individual platforms, percolation pits, and cut and filled slope protection structures are suitable for conserving soil and arresting water runoff. Hence, gardeners need awareness and development of skills to construct and establish these structures in their forest gardens.
Protection from wild animals
The most common wild animals that cause crop losses in forest gardens include boar, monkey, porcupine, palm civet and squirrel.
There are strategic approaches and potential management strategies, tested and available for effectively controlling the invasion of these animals. Some possible approaches are repelling techniques and translocation. Effective repelling techniques include the use of flashlights, guard dogs, firecrackers, catapults, and air rifles.
The Kandyan forest gardens collectively represent the oldest agroforestry system in Sri Lanka. More attention is required from researchers, agronomists, land use planners and policymakers as well as local farmers for conservation of this important agrarian heritage for the benefit of generations to come.
As global concern grows over the destruction of tropical forests, the loss of biodiversity and the need for sustainable agriculture for smallholder farmers, this forest garden system deserves more careful consideration.
The writer is a Freelance Agriculture Scientist in natural resource management.