240 
above four formula comprehensive can comprehensive describe 
a single land use types of spatial dynamics. 
3. THE PROCESSES OF LAND USE / COVER 
CHANGE AND TRENDS IN THREE GORGES 
RESERVOIR AREA AT NEARLY 30 YEARS 
3.1 The range of area change of land use 
Formula 1 indicates the range of six land use types on the 
Three Gorges reservoir in 1972 -1986. 1986-2000 and 1972- 
2000 periods were calculated (Table 1). 
in increasingly, at -0.91%, -0.70% Reforestation been checked 
to a certain extent. Grassland area has experienced first 
decreased and then increased the process, the range of area 
change of-1.42%, 3.59%; building area continued to increase; 
unused land area continued to decline, and its range of 
reduction growing. Water area continued to decline, the range 
of reduction is -1.38%, -1.19%. Through the above, the area of 
woodland and grassland view of the range of changes, returning 
farmland to forest and pastures are beginning to bear fruit. 
3.2 A single land use / cover types of dynamic change 
1972-1986 
the range of 
area change 
1986-2000 
the range of 
area change 
1972-2000 
the range of 
area change 
Farmland 
34204.60 
1.36% 
-20234.70 
-0.79% 
13969.90 
0.55% 
Woodland 
-27241.10 
-0.91% 
-20821.70 
-0.70% 
-48062.80 
-1.61% 
Grassland 
-9453.30 
-1.42% 
23675.75 
3.59% 
14222.45 
2.13% 
Construction sites 
3678.80 
10.44% 
18525.10 
47.59% 
22203.90 
63.00% 
Unused land 
-201.00 
-2.37% 
-303.15 
-3.66% 
-504.15 
-5.94% 
Waters 
-988.00 
-1.38% 
-841.30 
-1.19% 
-1829.30 
-2.56% 
Table 1. Area net change of the land use/cover in the study area at different periodsin lately fifty years (units: hm ) 
The results showed that from 1972 to 2000 nearly 30 years of 
time, the area of 6 land use types have occurred in different 
degrees, the area of 3 land use types decreased, while others 
increased. In the type whose area increased, the reduction of the 
woodland area was the biggest, which is 48062.80 hm 2 ; the 
reduction of water area was smaller than woodland, which 
reduce 1829.30 hm 2 ; the area of unused land reduced 504.15 
hm 2 ; In the type whose area decreased, construction is first, 
which increased 22,203 hm 2 ; the area of lawn increased 
14222.45 hm 2 ; the area of arable land increased 13969.90 hm 2 . 
In the reservoir of all types, in the past 30 years, at the 
magnitude of changes of area, the change of construction was 
the largest, which was 63.00%; unused land was Second, which 
was 5.94%; the range of area change of water, grassland, 
woodland and farmland were also reached 2.56%, 2.13%, 
1.61% and 0.55%. 
From the changes of the area of all types in 1972 -1986 and 
1986-2000, farmland area has increased prior to the reduction 
process, the range of area change were 1.36%, 0.79%; 
woodland area continued to decline, but the range of reduction 
According to the formula 2, 3, 4, 5 calculating the Three 
Gorges reservoir area nearly 30 years of all types of dynamic 
change indicators, calculated results are shown in table 2. 
The results showed : ® output speed : 1972-1986, the area of 
all types, the output speed is from the order of unused land, 
grass, water, woodland, farmland, and construction sites; in 
years 1986-2000 will become the order of unused land, 
grassland, farmland, forest land, waters, building sites. On the 
output speed of all types areas in two periods of comparison, in 
addition to construction sites, other types of land use in 1986 
and 2000 transfer rate was more than the fore periods. (2) output 
speed : 1972-1986 years, to the speed of all types, from large 
order to the small were construction land, farmland, grassland, 
unused land, woodland, water; 1986-2000, the order of the rate 
of all types were construction land, grassland, farmland, forest 
land, waters, unused land. On the transfer of all types of speed 
in two periods of change, output speed increased both. (D 
integrated dynamic degree: in 1972-1986, the composite 
dynamic degree of 6 land use types followed the order of 
construction land, unused land, grassland, farmland, waters and 
^"\t:he type 
Indicatofs^^^ 
of change 
the Period 
Farmland 
Woodland 
Grassland 
Construction sites 
Unused land 
Waters 
Transferrate (%) 
1972-1986 
0.01 
0.07 
0.14 
0.00 
0.20 
0.10 
1986-2000 
0.19 
0.18 
0.21 
0.00 
0.30 
0.14 
Output speed 
1972-1986 íT 
0.11 
0.01 
0.04 
0.75 
0.03 
0.00 
(%) 
1986-2000 
0.13 
0.13 
0.46 
3.40 
0.04 
0.04 
Integrated dynamic 
1972-1986 ífi 
0.11 
0.08 
0.18 
0.75 
0.22 
0.10 
degree (% ) 
1986-2000 íp 
0.32 
0.31 
0.67 
3.40 
0.33 
0.19 
State index 
1972-1986 íp 
-0.86 
0.83 
0.56 
-1.00 
0.76 
0.97 
1986-2000 
0.18 
0.16 
-0.38 
-1.00 
0.78 
0.46 
Table 2. The change indexes of the land use typein the study area at different periods