Abstract:
The integration of trees on farmlands has recently
received attention due to their contribution to liv
elihoods
improvement and climate change mitigation. They pro
vide ecosystem services (ESs) like climate change m
itigation, improvement of
soil fertility, provision of timber and fuelwood am
ong others. The choice of trees to plant depends on
the role the farmer intends to
put them into and the size of the farm. The trees c
an either be indigenous or exotic andare mostly pla
nted along farm boundaries, in
home gardens, as woodlots orientation among others.
This study was conducted in western part of Kenya
on farmlands that mostly
border the Kakamega Forest. The study soughtto dete
rmine abundance, distribution and biomass carbon st
ocks of
Grevillea robusta
and
Eucalyptus saligna
for enhanced climate change mitigation. A total of
(N=3,468) trees were inventoried in 80 farms with
a total
of 27.5ha. The average size of farms where the surv
ey was done was about 1.28±1.01 ha.
Eucalyptus saligna
had a tree abundance
1133 (33%) of the total trees sampled while
Grevillea robusta
had 2,335 (67%). Two sites were purposively selecte
d (Lubao and Tea
zone area). In the Lubao site,
Eucalyptus saligna
abundance was 627 (29%) while
Grevillea robusta
abundance was 1565 (71%) of
the total trees sampled. In Tea Zone site,
Eucalyptus saligna
abundance was 506 (40%) while
Grevillea robusta
tree abundance was
770 (60%). Total biomass estimated in the study are
a was 3.86±0.21Mgha
-1
(1.96Mg C ha
-1
). This was distributed as aboveground
biomass (2.8±0.12Mgha
-1
) and belowground biomass (0.87±0.41Mgha
-1
). There was no significant difference in biomass a
mong
farms in Lubao (F=43.12; p=0.34) and in Tea zone si
tes (F=53.12; p=0.23). Lubao site had an estimated
biomass of
1.97±0.023Mgha
-1
distributed as above ground biomass (1.31±0.043Mgha
-1
) and below ground biomass (0.67±0.023Mgha
-1
). Tea
zone site had an estimated biomass of 1.99±0.38Mgha
-1
. This was distributed as above ground biomass (1.5
8±0.023Mgha
-1
) and
below ground biomass (0.40±0.18Mgha
-1
). Biomass was significantly different among the ag
roforestry practices in Lubao (F=13.1;
p=0.002) and in Tea Zone (F=29.12; p=0.001). Hedger
ow had the highest biomass among the agroforestry p
ractices in Lubao
(1.91±0.16Mgha
-1
) and in Tea zone sites (1.7±0.23Mgha
-1
). Alley cropping that was only practiced in Lubao
had the least biomass
(0.0044±0.009Mgha
-1
). The twotree species provided benefits for househ
old use and at the same time for monetarysale. Fire
wood and
timber were the most mentioned (n=80). This was fol
lowed by construction material and fencing material
. These functions/uses were
most preferred by the
Eucalyptus grandis