Trees are useful for planting on external farm boundaries to separate legally defined land units. Trees are also planted on internal farm boundaries to separate different farming activities or sections of the same farm. Such tree planting practice is referred to as boundary tree planting and is commonly practiced in various parts of Kenya, including Kitui County. The County is situated in a semi-arid region with temperatures ranging between 260C - 340C and has bimodal type of rainfall with an annual range of between 300 mm – 1,050 mm. Senna siamea is one of the popular trees used for boundary planting in Kitui County.
The objectives of boundary tree planting are to:
- Demarcate and secure farm boundaries
- Offer greater visibility of the farm boundary
Senna siamea seedlings are usually established 2 m away from the common external boundary, and at a spacing of 2 m between seedlings. During the dry season, the planted seedlings are watered to enhance survival. The seedlings are also weeded in the first year. When the trees are about 4 years, selective removal is undertaken to attain a final spacing of about 4 m between trees. Prunning of the trees is carried out once a year to reduce shade. The prunnings provide mulch and firewood, while the pruned trees provide good quality timber. Trees are harvested when they are at about 20 years old. Wood is sold in the local markets for timber production. Senna siamea has coppicing ability, thus, upon harvesting, sprouting coppices are managed through selective thinning, leaving the best coppice to grow for the next crop of firewood and timber.
|Senna siamea on farm boundary
||A large Senna siamea tree on farm boundary
Boundary tree planting using Senna siamea has economic, social and ecological benefits. The tree produces firewood for domestic use, therefore saving the farmer time and money that could have been spent in search of the commodity. The species also produces timber for sale, improving farmer’s income. In addition, the trees on the boundary contribute to improved biodiversity on-farm by providing habitat for different bird species. Crop production is improved through enhanced soil fertility and stability as the trees act as wind breaks, control soil erosion, and provide mulch. The trees also have aesthetic value and provide shade.
Boundary tree planting has been found to be successful in Kitui County, Kenya, as many farmers have adopted the practice. However, for the good practice on boundary tree planting to be successful, there is need for:
- Secure land tenure
- Availability of seedlings at the onset of the planting season
- Training farmers on boundary tree establishment and management techniques including, species selection to avoid competition with inter-planted crops
To maximize ecological benefits of boundary tree planting, an under-storey crop such as sisal can be planted between the trees to optimize benefits such as soil erosion control and to enhance plant diversity on-farm.
Despite the multiple benefits accrued from tree boundary planting, some challenges are experienced which include;
- Labour, which is intensive and expensive
- High cost of seedlings
- Destruction of saplings by livestock
- Shading of adjacent crops.
Farm boundary conflicts can be minimized by marking land boundaries through planting suitable tree species such as Senna siamea.
Boundary tree planting is an effective practice for demarcating farm boundaries. Trees planted can provide multiple benefits such as firewood and timber as well as offer environmental resilience.
The authors are grateful to Mr. Gedion Kilunda of Nzangathi Village, Kitui County, Kenya for provision of information on boundary tree planting, which enabled documentation of this good practice.
Kevin Muema,.Samuel Wakori,.Sylvia Mwalewa, Omondi Oketch, Josephine Wanjiku Esther Manyeki and James Kamiri Ndufa