Planting Bamboes and Grevillea for Riparian Land Conservation [Kenya]

technologies_1135 - Kenya

Completeness: 78%

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:
SLM specialist:

F. K. Nyamu Joseph

Saba Saba WRUA


Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
FAO (FAO) - Italy
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Saba Saba Water Resource Users Association (Saba Saba WRUA) - Kenya

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:


2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

The technology is based on tree plantation of several species (i.e. Grevillea robusta, Psidium guava, Bambusa vulgaris ) along the riparian land of the farmer.

2.2 Detailed description of the Technology


The practice carried out voluntary by the farmer consists of planting trees at the edge of the river bank and in its proximity.

Purpose of the Technology: By increasing vegetation cover (started 10 year ago) the intention of the farmer is to reduce and control bank erosion and landslides in the riparian land.
The degradation in this area is in fact evident and it is partially explained by the reduced vegetative cover. The planted trees help to maintain water quality by filtering silt and organic materials from rainwater runoff from the upper area and at the same time reinforce the streambank to control erosion. Another important environmental benefit is the increased carbon allocation from the new root systems.
The farmer also mentioned the interest to continue expanding tree plantation also in view of carbon credit and financial support from local authorities: in particular bamboo, which reaches maturity in few years, can be harvested after about two years and is easy to propagate (vegetatively).
Grevillea trees (timber) are seen by the farmer as a form of saving, and sold out when the farmer is in need of cash, earning between 800 up to 1500 KSh (Kenyan Shillings), depending on the size of the tree and the costs for cutting- transportation (e.g. machine operator between 500-700 KSh).

Establishment / maintenance activities and inputs: The initial inputs for the establishment of the vegetative practices concern mainly labour (e.g. planting trees) and the cost of the seedlings (10 KSh seedlings of Grevillea, 20 KSh of Guava); generally these activities are carried out at the beginning of the rainy season. Pruning of Grevillea is done every three seasons.

Natural / human environment: The climate is sub humid with two rainy seasons (the first starts around March and the second around October). Near the river the area is characterized by gentle slope and deposition of sediments and bank erosion are the main processes; the risks of further degradation and water pollution are reduced by the riparian vegetation and thanks to the good land management practices of the surrounding farmers. The riparian land is the area of min 6-30 m around the river and it is considered by law a protected area; therefore it should be left intact from any human activity (Water Act, 2002). Indeed, the 'control' and daily management is carried out by the riparian farmers in collaboration with Sabasaba WRUA and WRMA, the official authority for the management of the water of the river and the riparian land.
In this site in particular, the water of the river is considered clean by the farmer interviewed, despite the fact that during rainy seasons the sediment loads affect the quality of the water.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment



Region/ State/ Province:


Further specification of location:

GATWAMIKWA village, Kagurumo sublocation, Muthithi location


Total area covered by the SLM Technology is 0,1 ha m2.

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through land users' innovation
Comments (type of project, etc.):

Since year 2000 the farmer has been adopted SWC practices: this in reply to the prolonged degrading situation at the hedge of the river: 'natural vegetation was 'not good' and so 'it was no properly holding the soil', he said.

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • reduce, prevent, restore land degradation

3.2 Current land use type(s) where the Technology is applied



  • Tree and shrub cropping
Tree and shrub cropping - Specify crops:
  • mango, mangosteen, guava
Number of growing seasons per year:
  • 2

Longest growing period in days: 122 Longest growing period from month to month: from about March to June Second longest growing period in days: 61 Second longest growing period from month to month: from about October to November

Forest/ woodlands

Forest/ woodlands

  • few lines of Grevillea/Bamboes (According to the definitions adopted FAO (FRA, 2010) the land could not be considered as wooded land (less than 0.5 ha).)
Type of tree:
  • Bamboo bamboo
  • Grevillea robusta
Products and services:
  • Nature conservation/ protection
  • source of cash

Tree plantation of several species (i.e. Grevillea robusta, Psidium guava, Bambusa vulgaris )

Major land use problems (compiler’s opinion): Risk of bank erosion and deposition of sediments in the river. See Appendix 3. Fig. 2.

Major land use problems (land users’ perception): Bank erosion. See Appendix 3. Fig. 3

Other type of forest: few lines of Grevillea/Bamboes: According to the definitions adopted FAO (FRA, 2010) the land could not be considered as wooded land (less than 0.5 ha).

Problems / comments regarding forest use: Bamboos are planted because of environmental benefits of this plant to stabilize riverbank. Other potential uses: e.g. wood is used to make baskets, fences and various kind of construction; leaves are used to feed chickens. The hollow sections between nodes are used to make containers. Indeed, the farmer let neighbours to clear and use some bamboos.

Forest products and services: nature conservation / protection

Other forest products and services: source of cash

3.5 SLM group to which the Technology belongs

  • improved ground/ vegetation cover
  • improved plant varieties/ animal breeds

3.6 SLM measures comprising the Technology

agronomic measures

agronomic measures

  • A7: Others
vegetative measures

vegetative measures

  • V1: Tree and shrub cover

Main measures: vegetative measures

Secondary measures: agronomic measures

Type of vegetative measures: aligned: -along boundary, scattered / dispersed

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wm: mass movements/ landslides
  • Wr: riverbank erosion
water degradation

water degradation

  • Hp: decline of surface water quality

Main type of degradation addressed: Wr: riverbank erosion, Hp: decline of surface water quality

Secondary types of degradation addressed: Wm: mass movements / landslides

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Poor vegetation cover, mainly herbaceous), Heavy / extreme rainfall (intensity/amounts) (Especially during wet seasons: March-June and October-November)

Secondary causes of degradation: other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Footslope area (sediments deposition)), land tenure (Previous poor management SWC measures, especially in the upper areas)

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • prevent land degradation
  • reduce land degradation

Secondary goals: prevention of land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Bamboos planted at the hedge of the river; a line of Grevillea, which demarcate the farmer's property and Guava seedlings planted in the riparian land.

Technical knowledge required for land users: low (E.g. Planting bamboos is easy since colony species which use rhizome to spread.)

Main technical functions: control of dispersed runoff: impede / retard, improvement of ground cover, stabilisation of soil (eg by tree roots against land slides), improvement of water quality, buffering / filtering water

Secondary technical functions: improvement of topsoil structure (compaction), increase of infiltration, increase / maintain water stored in soil, sediment retention / trapping, sediment harvesting, promotion of vegetation species and varieties (quality, eg palatable fodder)

Aligned: -along boundary
Vegetative material: T : trees / shrubs
Number of plants per (ha): 25
Vertical interval within rows / strips / blocks (m): 1.5
Width within rows / strips / blocks (m): 0.5

Scattered / dispersed
Vegetative material: T : trees / shrubs, F : fruit trees / shrubs
Number of plants per (ha): 55
Vertical interval within rows / strips / blocks (m): few cm

Trees/ shrubs species: (25) Grevillea robusta (Mũkĩma)

Fruit trees / shrubs species: (5) Psidium guajava (Mũbera), (50 sps) Bambusa vulgaris (Mũrangi)

Slope (which determines the spacing indicated above): 3%

4.2 General information regarding the calculation of inputs and costs

Specify currency used for cost calculations:
  • USD

4.3 Establishment activities

Activity Timing (season)
1. Digging holes / Planting pits (1 feet×1feet Grevillea) Beginning of the season (March/April)

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Digging holes Persons/day 4.0 1.75 7.0 100.0
Plant material Seedlings Grevillea pieces 25.0 0.28 7.0 100.0
Plant material Seedlings Guava pieces 5.0 0.2 1.0 100.0
Total costs for establishment of the Technology 15.0
Total costs for establishment of the Technology in USD 15.0

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Pruning Grevillea and let branches dry for firewood Every 3 seasons
2. Clearing Grevillea for sale When in need of cash (not regularly), at least 5 years after planting

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Pruning Grevillea Persons/day 1.0 4.0 4.0 100.0
Labour Clearing Grevillea for sale Persons/day 1.0 7.0 7.0 100.0
Total costs for maintenance of the Technology 11.0
Total costs for maintenance of the Technology in USD 11.0

Machinery/ tools: shovel, machete, hoe

The costs summarized above have been calculated considering one year activities; Bamboos do not require establishment/maintenance costs and therefore do not appear in the balance sheet costs.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

An important constraining factor is labour cost for clearing Grevillea.

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specifications/ comments on rainfall:

Two wet seasons: March-June and October-November. Dry periods: December- February and July- October

Agro-climatic zone
  • sub-humid

Thermal climate class: subtropics. June, July and August

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Comments and further specifications on topography:

Altitudinal zone: 1434 m a.s.l.

Landforms: Footslopes are the the areas in which this technology has maximum extent.

Slopes on average: Gentle in the riparian land.

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • medium (loamy, silty)
Topsoil organic matter:
  • low (<1%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil fertility is low

Soil drainage / infiltration is medium

Soil water storage capacity is medium

5.4 Water availability and quality

Ground water table:

> 50 m

Availability of surface water:


Water quality (untreated):

good drinking water

5.5 Biodiversity

Species diversity:
  • medium

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • commercial/ market
Off-farm income:
  • > 50% of all income
Relative level of wealth:
  • rich
Individuals or groups:
  • individual/ household
Indicate other relevant characteristics of the land users:

Population density: 10-50 persons/km2

Annual population growth: 2% - 3%

Off-farm income specification: The farmer is rich because he owns 3 acre of land and livestock, assets (electricity) which are above the average standards of the community. The farmer is retired from an accountancy service position several years ago.

Market orientation of production system: Timber of Grevillea is sold in feet.

5.7 Average area of land used by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha

The area for planting Grevillea is just a strip along the riparian land.

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • individual, titled
Land use rights:
  • individual
Water use rights:
  • open access (unorganized)

Water use rights depend on the use: open access for drinking and domestic uses.

5.9 Access to services and infrastructure

  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts


fodder production


wood production


production area

Water availability and quality

irrigation water availability

Comments/ specify:

Could be the case for Napier grass if long dry spells occur

demand for irrigation water

Income and costs

expenses on agricultural inputs


farm income


diversity of income sources




Socio-cultural impacts

food security/ self-sufficiency

Comments/ specify:

Indirectly another source of income that could improve in maintaining FS conditions at household level

community institutions

Comments/ specify:

The shared knowledge/benefits help to build community solidarity, strengthening linkages between farmers

SLM/ land degradation knowledge

Comments/ specify:

The importance of the benefits of Bamboos and other sps. to the river in preventing erosion and improving water quality has encouraged neighbours to adopt the same veg. measures (fig. 8)

Ecological impacts

Water cycle/ runoff

water quality


surface runoff




soil moisture


soil cover


soil loss

Biodiversity: vegetation, animals

biomass/ above ground C


habitat diversity

Comments/ specify:

Especially Bamboo's canopy which create a good habitat for birds

pest/ disease control

Comments/ specify:

Expanding bamboo's plantation could attract rodents/rats feeded off the bamboo's fruits, grains.

Other ecological impacts

Carbon credit

Comments/ specify:

Beginning phase of the process of acquiring CC.

6.2 Off-site impacts the Technology has shown

water availability


reliable and stable stream flows in dry season


downstream siltation


groundwater/ river pollution


buffering/ filtering capacity


6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change
Season increase or decrease How does the Technology cope with it?
annual temperature increase not known

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local rainstorm well
local windstorm well
Climatological disasters
How does the Technology cope with it?
drought not well
Hydrological disasters
How does the Technology cope with it?
general (river) flood well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
reduced growing period not known

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

neutral/ balanced

Long-term returns:

slightly positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

neutral/ balanced

Long-term returns:

slightly positive

6.5 Adoption of the Technology

  • single cases/ experimental
Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 0-10%

100% of land user families have adopted the Technology with external material support

There is a moderate trend towards spontaneous adoption of the Technology

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Grevillea is good for timber producion.

How can they be sustained / enhanced? More trees could be planted, but because of 'lack of money' he can not afford it.
Bamboos are good in holding the soil

How can they be sustained / enhanced? Leaves could be actually used to feed chickens; planting the 'giant bamboos' also for food consumption.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
The Technology is easy to adopt, specially Bamboos plantation, since it does not require significant input and knowledge

How can they be sustained / enhanced? It could be implemented in the long run also because the farmer is willing to earmark part of his land for a nursery. The intention is to support the nursery with free seedlings, which could be later distributed among the riparian farmers of the community.
Bambos spreads easily through cuttings and it has different beneficial uses (baskets, fences and various kinds of construction).

How can they be sustained / enhanced? Other type of Bamboos could be used as: Dendrocalamus giganteus for food consumption and Arundinaria alpina.
Grevillea plantation has benefits in holding soil. It helps to reduce evaporation from the soil since it makes good shadow.

How can they be sustained / enhanced? To increase biodiversity other indigenous sps. could be also planted, among others:
Croton megalocarpus (Mũkindũri) a medicinal tree that attracts a lot of bees when in flower, resulting in excellent white honey. The seeds contain oil.
Sesbania sesban/keniensis (Mwethia), a nitrogen fixers plant which therefore helps to increase soil fertility.

7. References and links

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Kikuyu botanical Dictionary 2nd Ed.:A guide to plants names, uses and cultural values. Muruga Gachathi, 2007.

Available from where? Costs?

KEFRI, Nairobi

7.3 Links to relevant online information

Title/ description:

Smallholder timber and firewood marketing in the coffee and cotton/tobacco zones ofeastern Mount Kenya. Holding et al., 2006.


Title/ description:

Lovett, S. & Price, P. (eds), 2007, Principles for riparian lands management, Land & Water Australia, Canberra. (Ch. 2 Diversity and dynamics of riparian vegetation, Ch.6 The influence of riparian management on stream erosion)


Title/ description:

Water Act (The), 2002. N8. The National Water Services Strategy

URL: and

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