ildi et al. 2006).
cach land use,
is the dissection
ty weighted by
1.2012).
' on what has
s of the change
etit et al. 2001;
31.2008). In this
ntegrated using
1-based change
poral trajectory
sponding to its
n 1986 to 2006
r example, the
eaning that the
st in 2000 and
d
e change
86-2006 were
e of the forest
. It was found
t two decades.
otal land area.
1 open forest,
-2006.The net
t decreased by
2.1 per cent of
period, loss of
han that from
f the total area.
past 20 years,
' attributed to
; Closed Open Other
period P forest Sum forest forest
1986 area -83.16 -3.85 -20.45 49.91
-2000 ^ rate(94) 0 0 -0.10 0.90
pe area -1249.2 47.52 -60.68 0.34
E rate(%) -0.50 -0.70 -0.70 0
458 change -1332.36 5138 -81.13 50.25
3 rate(%) -0.19 -0.25 -0.29 0.64
Table 1. The area changes of different forest types (km?)
RE
asics RETR
x
=
Figure 2. Forest in study area in 1986(a), 2000(b), 2006(c)
In summary, forest has decreased at an annual change rate of -
0.19% during 1986-2000. Closed forest was destroyed with
annual loss rate of -0.5% from 2000 to 2006. The open forest
decreased dramatically with annual rate of -0.7% in the same
period. Shrub forest shrunk in area between 1986 and 2000 at
loss rate of -0.25%. There was an increase of other forest land
with annual area change rate of 0.90% (from 1986 to 2000) and
0.64% (from 2000 to 2006) respectively. The speed of
deforestation from 2000 to 2006 was faster. The change rates of
various forests were relatively high showing a negative state.
4.2 Forest Fragmentation
Figure 3 shows the landscape metrics for forests at class level in
different historical years. During the past 20 years, the numbers
of forest patch increased slightly, while the average patch area
decreased 96 ha. Forest decreased in the average size of patches
potentially resulting from cultivation and degradation. From
1986 to 2006, the PD of forests increased from 0.059 per 100 ha
to 0.062 per 100 ha. Forest land in this region affected by
human activities have lower AMWPFD values (<1.30).
AWMPFD of forests decreased slightly indicating that forest
patch shape tended to be regular and simpler indicating more
human influence during 1986-2006. The averages patch area of
closed forest decreased 2737ha resulting from logging and
cultivation. The MPS values of shrubs and open forest
decreased while averages patch area of other forest increased
probably due to the afforestation encouraged by the government.
The AWMPFD of closed forest and shrub decreased by 0.002
and 0.003, respectively. It was concluded that forestland
experienced the process of substantial clearing and
fragmentation in the past 20 years.
2500
2000
1500
=
1000
500
at D
1986 2000
M Closed forest CJ Shrub [S Open forest 0 Other forest E Total
12000 -
b
10000 -
8000 -
6000 -
4000 |
2000
a JF a.
1986 2000 2006
O Closed forest [1 Shrub 0 Open forest CJ Other forest C1 Total
MPS
$50 -
300 -
250 |
200 |
PD
1986 2000 2006
DJ Closed forest (3 Shrub &) Open forest CJ Other forest & Total