5.
Resu
lt
s
an
d
D
i
scuss
i
o
n
The wave heights decreased whe
n
t
he waves propagated further into the mangrove field. For a 50 m wide
R
hizophora
forest, the wave reduction was over 52 % compared to 29 % by bare land
w
hi
c
h i
s
n
earl
y
two
t
imes larger (
Fig
3
a
).
T
he
w
a
ve
r
educ
ti
o
n in
b
ar
e
lan
d
w
a
s
mainly caused by the bott
o
m fri
c
ti
o
n
.
F
o
r ar
e
a
with mangroves,
t
h
e
r
e
w
a
s
a
n
additional friction contributed by the
m
angrove trunks and root system,
he
n
ce
i
mposing
h
ighe
r
r
esistance to incoming waves.
I
t i
s
al
so
s
h
ow
n that t
h
e wave reduction was greater when the
m
angrove models we
r
e arranged in staggered order compared to tandem.
For 100 m wide mangrove forest,
t
h
e
w
a
ve
r
educ
ti
o
n f
o
r tan
de
m an
d
s
taggered arrangement of trees w
e
r
e 78 % and 85 %, respectivel
y
(
Fig
3
a
)
.
For the case of staggered arrangement, the waves could not propaga
t
e freely through
t
he gaps betwee
n
m
angrove tree
s
,
hence more wave energy was dissipated.
However
,
the difference i
n
w
a
ve
r
educ
ti
o
n f
o
r
bo
th
arrangements was less tha
n
1
0
%, which is not significant. This might be due to the structure of
R
hizophora
roo
t
s
w
h
ich spread widely and in most cases overlap with roots of other trees. Since most of the waves were
attenuated by the
R
hizophora
r
oots, the wave reduction was still considerably high
r
egardless of the tree
arrangement
(
t
andem or staggered orde
r
)
.