Criteria or principles for agroforestry system classification

The most common criteria’s for the classification of agroforestry systems are the structural basis, in which components of agroforestry (forestry, agriculture and livestock) are combined. Other criteria’s include its function, socio-economic scale and management level and ecological basis.

The major agroforestry systems of the high mountain and mid-hills of Nepal are home gardens, agri-silviculture system (planting trees along terrace bunds, borders and slopes), silvi-pastoral system (kharbari), agri-silvi-pastoral system (typical hill farming, in which agriculture crops are grown on terrace flat, trees on terrace bunds and borders, and grasses on terrace slopes-kanla), and alley cropping (promoted by the Leasehold Forestry and Livestock Program/FAO), where as this in Terai and inner Terai are home gardens, agri-silviculture system, silvi-pastoral system, horti-silviculture system and silvi-fishery or aqua-silviculture. Taungya agroforestry system was also practiced in Terai and inner Terai of Nepal for plantation establishment. Shelter belt establishment and management practice is common in fruit orchard of Terai and inner Terai of Nepal. Apiculture, sericulture, and shifting cultivation can also be considered as minor agroforestry systems.

According to Nair (1987), following are the main principles or criteria’s for agroforestry system classification:

1. Structural basis

It refers to the composition of components such as forestry, agriculture and livestock. This component composition can be in time (temporal or short duration and long duration) and space (dense or spatial), and other terms are used to justify the various arrangement made for system development.

• Considers the composition of components including spatial and mixture of the woody components.
• Vertical stratification of the components mix and temporal arrangement of the different components.
• The spatial arrangement of trees in agroforestry system can be categorized as mix dense (like in home garden), mix sparse (like in pasture land or Kharbari), strip of trees, and boundary plantation.

2. Functional basis

It refers to the major function or role of the system mainly of the woody components of agroforestry system. These functions can be productive (fuel wood, fodder, timber and leaf litter), protective (shelterbelt, wind break and soil conservation) and ameliorative means soil fertility improvement.

3. Socio-economic basis

Agroforestry system under this category can be classified based on 1) level of inputs for management such as high inputs (agro-silviculture) and low inputs (silvi-pastoral system and shifting cultivation), 2) intensity or scale of management, and 3) commercial goals.

4. Ecological basis

It refers to the environmental condition and ecological suitability of systems, based on the assumption that certain types of systems can be more appropriate for certain ecological conditions; i.e., there can be separate sets of agroforestry systems for arid and semiarid lands, tropical highlands, lowland humid tropics, etc.

Agroforestry systems found in low lands and high altitude are shelterbelt and wind breaks. This system is also useful for arid or semi arid regions.

Ecologically, agroforestry needs to be practiced for the protection of crops, fruits, soil and other resources from cold and dry winds, extreme heats and snow, and water.

Agroforestry practice also improves ecosystems, increases landscape diversity, and creates additional wildlife habitats. The best systems under this ecological consideration are shelter belts, multi-storey agroforestry system, alley cropping and mix intercropping.