Agroforestry, as we have learned from the two previous articles, is a dynamic, ecologically based, natural resource management system that, through the integration of trees in farm- and rangeland, diversifies and sustains smallholder production for increased social, economic, and environmental benefits.

Agroforestry seeks to optimise the interaction between woody (trees and shrubs) and non-woody (crops and pasture) components, and with the addition of livestock to achieve higher productivity, sustainability and a greater diversity of products from the land.

Agroforestry combines agriculture and forestry techniques to:

•improve resilience of farmers over time by mitigating deforestation and land degradation;
•address climate change and its variability;
•increase farm productivity;
•enhance households’ access to diverse wood and non-wood products at different times of the year;
•diversify a household’s livelihood sources and increasing their income;
•improve their food security situation; and thus
•alleviate poverty.

Agroforestry in three regions of Kenya

Agroforestry practices in three regions in Kenya, namely the humid highlands, humid lowlands and arid and semi-arid lands (ASALs).

Humid highlands

The humid highlands cover areas with a minimum altitude of 1 980 m above sea level and a minimum annual rainfall of 1 000 mm.

These areas include all humid agroclimatic zones in Mt Kenya region, the Rift valley region and western Kenya.
Diverse agroforestry practices are used in this region as an important source of livelihood for many households.

These practices include:

Woodlots

Areas designated for the planting of trees are known as woodlots. These are planted for timber, poles for electricity transmission and construction, as well as charcoal and fuelwood. Vegetables or crops are often intercropped in the woodlot when the trees are still small, but eventually the whole lot is used for wood production. Woodlots are usually planted on land that is too poor for other crops. However, when the wood production is profitable as a crop, the woodlots may be planted on better soil, especially if there is a need for timber, that is near settlements. If the woodlot is to provide fuelwood, it is suitable to have a small woodlot near the house.

Woodlots can be planted from seedlings or, in some species, by direct sowing of seed. Raising seedlings may be a better option. Initial spacing can be dense, as the trees will be used for thin poles, firewood or the making of masks. Gradual thinning will allow the trees to grow to the desired size, while smaller saplings can be harvested. Woodlots with young trees must be protected from livestock and fire. Newly established woodlots can be intercropped with vegetables or other crops, which will help with weed control. Keeping a woodlot is labour-intensive as the trees must continually be thinned and pruned to provide good-quality poles and timber. A natural woodlot also requires maintenance through selective bush clearing and protection in the early stages. When woodlots are planted next to a crop field, a trench of 50 to 80 cm deep can keep the tree roots out of the rooting zone of the crop.

Fast-growing tees in woodlots, like eucalyptus, can be used since the land is used only for the trees, as nothing grows underneath them. A high level of wood production for domestic or cash income purposes can thus be achieved. Trees in woodlots can also be a good way of making some savings. The negative aspect is that already scarce land is taken out of agricultural production.

Boundary planting

Boundary planting with fodder shrubs used for livestock feeds, exotic timber species used for timber, poles and fuelwood, and indigenous trees that are used to generate income.
Tree growing on farm boundaries is a common practice, but it requires agreement between the neighbours to avoid conflict. There are different ways of sharing trees planted on a boundary, like planting two rows of trees, but this takes up a lot of space on the already tiny farms. Neighbours can also agree to use every second tree, or a number of trees in a different section.

Care must be taken to prevent different tree types from outcompeting each other. Seedlings can be spaced close together and thinned out for poles or firewood later to allow each tree enough room. Seedlings are commonly used, or trees that grow wild can be transplanted.

Homestead planting

Homestead planting may include indigenous or alien trees planted for farm protection, livestock fodder and fuelwood.

Trees of different heights can be grown together in multi-storey systems to make maximum use of the little space available. Fruit trees are planted for their fruit and medicinal value. The trees are intercropped with vegetables. Waste water and chicken manure are used to invigorate growing.

The biggest advantage of homestead planting is that the produce of these trees is available at hand. All the products and services can be useful. Some species produce a lot of litter which may add to the work of keeping the homestead tidy. Some trees, like bamboo and mango trees, may attract snakes. Trees with brittle branches and a vigorous root system should not be planted close to homes.

Alley cropping or strip planting along contours

Alley cropping or strip planting along contours are planted for soil protection and improvement, livestock feed, timber and fuelwood. In alley cropping, crops are grown between lines of trees and or shrubs that are managed and spaced at regular intervals in cropland. Hedgerows require many trees or shrubs, and a cheap propagation method is called for. Direct seeding or use of cuttings are ideal, but seedlings should be raised in on-farm nurseries. On flat land, hedgerows must be oriented in an east-west direction to reduce shading. On sloping land, hedgerows must be oriented along the contours.

Scattered trees in croplands and pasturelands

Mainly fruit trees and indigenous tree species are planted in cropland for their fruits for own consumption and selling the excess for extra income. Trees in pasturelands are planted for fuelwood, fodder and their medicinal value.

Riverbank, lakeshore or terrace planting

Mostly indigenous species and fruit trees are planted for stabilisation of riverbanks and lake shores and terraces, as well as for their fruit as food.

Context of agroforestry in humid highlands

The humid highlands are home to a thriving dairy sector. To counter the high cost of livestock feeds, farmers with a low income have to make use of low-cost agroforestry resources to boost milk production with fodder shrubs. Some fodder shrubs are known to increase milk production and butterfat percentages. Tea and coffee are the main cash crops for smallholder farmers. Coffee performs well under partial shading of indigenous trees, among others, Grevillea robusta planted within the farming system.

Deforestation, driven by a growing population’s demand for fuelwood, construction materials and alternative sources of food and income, is increasing at an alarming rate. The depleted forests and loss of ecosystem functionality, as well as concerns about climate change, are eliciting a lot of effort from government, NGOs, and communities to restore forests by intensified tree planting campaigns.

The highlands have the highest population numbers. The average size of smallholder farms is 1,2 ha, but because of adequate rainfall, the land has good farming potential and farmers are willing to invest in high-value marketable crops. However, some of these crops do not tolerate shade, which limits tree planting to low density planting on the farm boundary. Some areas, such as around Mt Kenya, have a good tree planting culture and more trees are included in croplands. Fast urbanisation is changing land use from agriculture to real estate. For example, in Kiambu county, large tracts of coffee farms are turned into real estate developments. If poor farmers sell their land, it could lead to an increase in deforestation, unless value chain innovations lead to urban and peri-urban agroforestry.

Source references
Wanjira, E.O., Muriuki, J. (2020) Background study for preparation of Kenya National Agroforestry Strategy (2020 – 2030). World Agroforestry

https://www.ctc-n.org/system/files/dossier/3b/A%20review%20of%20agroforestry%20status%20of%20Kenya.pdf

Tengnäs B. (1994.) Agroforestry extension manual for Kenya. Nairobi: International Centre for Research in Agroforestry. Agroforestry extension manual for Kenya. World Agroforestry Centre DC: 634.0.26:374.6(676.2) ISBN
92 9059 116 1
https://apps.worldagroforestry.org/Units/Library/Books/Book%2006/html/publisher.htm?n=1