Journal of Geoscience and Environment Protection
2014. Vol.2, No.1, 12-14
Published Online January 2014 in SciRes (
SWCF of Forest in Three-Gorges of Yangtze River
Kang Chen
Beijing SWC Ecological Engineering Consulting Co., Ltd., Beijing, China
Received ********* 2014
In Qinjiagou watershed of Three-Gorge of Yangtze River, 18 indices were selected from canopy layer,
litter layer, soil layer and topography to evaluate the soil and water conservation capacities of four com-
mon plantation types by ideal point method. Results indicated that the broadleaf plantation of robur (Li-
thocrpus glabra) and Chinese gugertree (Schima superba) (LS) has the biggest soil and water conserva-
tion capacity. The rank of three other plantation types from big to small is the mixed broadleaf plantation
of sweetgum (Liguidambar formosana), Chinese gugertree and camphor tree (Cinnamomum camphora)
(LSC), the mixed broadleaf-conifer plantation of Chinese fir (Cunninghamia lanceolata), Masson pine
(Pinus massoniana) and Chinese gugertree (CPS), and the mixed Pine plantation of Chinese fir and Mas-
son pine (CP). Under the same climate and topographical condition, the broadleaf plantation has better
soil and water conservation capacity than the conifer plantation. Sensitivity analysis showed that the three
most sensitive indices are soil non-capillary porosity, soil aggregation, and soil initial infiltration rate. The
litter amount and soil properties are the most important indicators of soil and water conservation capacity
of plantations. Therefore, suitable measurements such as deep tillage should be taken to improve the
properties of soil under different plantations.
Keywords: The Three-Gorge Area; Soil and Water Conservation; Function; Soil Properties; Sensitivity
Soil erosion is one of the biggest environmental problems in
the Southwest region of China. Many measurements have been
taken to protect soil and water resources. Researches indicated
that various types of plantations are all able to reduce surface
runoff and soil erosion effectively (Woodward et al., 1995;
Jiang et al., 2007), and their function was affected by human
and natural disturbances (Noske et al., 2010; Uzun et al., 2011).
In the upper reaches of the Yangtze River, people have rep-
lanted most of farmlands with Chinese fir (Cunninghamia lan-
ceolata), Masson pine (Pinus massoniana), robur (Lithocrpus
glabra), sweetgum (Liguidambar formosan), camphor tree
(Cinnamomum camphora) and other tree species. Are these
plantation types suitable for reforestation, and are they helpful
to protect soil and water? The information is urgently needed to
understand soil and water conservation capacity of different
plantation types.
Methods and Materials
Study Area
Simian Mountain, belongs to the Three Gorges Reservoir
Area, is a typical case in terms of its complexity of natural en-
vironment and fragility of ecosystem in China. The soil erosion
is posing a serious threat to the ecological security and regional
sustainable development in upper reaches of Yangtze River.
The study area, Qinjiagou watershed (28˚31ʹN - 28˚46ʹN,
106˚17ʹE - 106˚30ʹE), is situated in the middle part of Simian
Mountain, Southwest of China. The forest land of Qinjiagou
watershed belongs to the upstream of Yangtze River. The alti-
tude is from 900 m to 1,500 m. Soils are mainly yellow loam
and purple soil, which is infertile, with a depth ranging from 10
to 70 cm. The representative types in Simian Mountain are
mixed forest of CP, CPS, LS, LSC. All the four plantation types
were planted in 1999, with 1 ha of LSC, CP, CPS, and 0.8 hm2
of LS. The previous shrubs were cut off before new plantations
were planted, but the litter is kept. There was no management
after the plantations were planted except irrigation in spring.
Samples Collection and Treatment
Ideal Point Method
Ideal point, a popular method for multiple objective deci-
sion-making, is objective thus avoiding large deviation due to
subjective opinion (Henry et al., 1989; Zhang et al., 2006; Ha-
gemann, 2007). That method could reduce the disturbance of
subjectivity in the course of assessment, and reflect the contri-
bution of each index to regional ecological safety more objec-
tively (Jia et al., 2006). Therefore, normalizing indices and
weighting determination was dealing with the above methods.
Sensitivity Analysis
Sensitivity analysis is necessary for evaluation (Chen, 1987;
Fan et al., 2004). The analysis will determine the certainty of
the rank of every two plantation types. Taking
as the pos-
sibly changed value of
, then
( )
ijjk k
yV yV
= −
()( )
ii j
k ij
yy V
∆= − =
min ,max
kij ij
y yy
, the change of
will not
induce the change of
. When
is very close to
, the
original rank is not steady.
is the sensitive index. If
very close to
when the Δ value belongs to
[ ]
, it
means that
is sensitive. And the lower the value is, the
more sensitivity indices are. If the numbers of sensitive indices
between two plantation types are more than 3, the rank of them
is uncertain.
Results and Discussion
Plant Investigation
In July 2009, three 20 × 20 m2 plots were established at each
plot of four plantation types in study area. The height of all
trees was measured. The number of trees in each subplot was
counted and recorded. In each 20 × 20 m2 plot, four 5 × 5 m2
subplots were established for investigation of shrub diversity.
The number and names of the different shrubs were recorded.
In each shrub plots, two 1 × 1 m2 subplots were established for
investigation of grass diversity and the names and amounts of
the different grasses were recorded. Five 1 × 1 m2 subplots
were randomly chosen in each 20 × 20 m2 plots and leaf litter
fall was sampled. A total of 15 leaf litter fall samples were
taken in each plot of every plantation type. The maximum wa-
ter capacity of litter was measured by putting leaf litter fall in
water 24 hrs.
Soil Properties
In June 2009, soil samples for physical properties measure-
ments were collected from each location of plantation types.
Five replicated soil cores for bulk soil density, total porosity
and non-capillary porosity were taken in each 20 × 20 m2 plot
along a diagonal transect. Analyses of physical soil properties
were conducted. Three composite surface soil samples were
collected from the plots of each plantation. The soil samples
were sieved to pass a 2 mm mesh and the percent of soil par-
ticles bigger than 2 mm equals the percent of gravel in the soil.
The infiltration rate (IR) of the soils was measured by using a
double-ring infiltrometer with a 22 cm outer diameter, a 10.5
cm inner diameter and a height of 25 cm (Song et al., 2007).
Organic matter of the soil was determined by an oil bath-
K2Cr2O7 titration method.
Implementing Ideal Point Method
Values of All the Indices
18 indices were selected for ideal point model. That is one of
differences from the previous research (Truman et al., 1990;
Deuchras et al., 1999). There into two indices, aspects and roots
distribution, are qualitative indices obtained by the method of
expert’s gradation according to the studies about the relation-
ship between indices and soil erosion. And the other 15 indices
values are all obtained from field measurements.
Normalization of Indices
The evaluation system is composed of 4 programs (4 planta-
tions) and 18 indices. Then, the original matrix of the evalua-
tion system is
46 2.87 300.15202.7919.170.2371.096 0.049 0.186 0.397 0.085 4.53 0.1810.7536901161
702.2700.03191.82 16.820.1131.033 0.031 0.313 0.502 0.1125.04 0.3717.4238.5 501160
78 3.26 30 0.043246.94 25.430.1341.1390.097 0.238 0.484
X=0.1275.240.3537.923690 1166
55 3.83 500.2664.476.040.0691.236 0.117 0.203 0.525 0.126 5.29 0.3010.08 28.8 701170
The matrix after normalization is
( )
4 18
00.411000.7580.67710.6900.20900 0 0 00.0240.25810.9
0.75010.556 0.6980.556 0.2621010.820 0.643 0.67110.263001
10.65001110.387 0.478 0.7670.409 0.68010.9340.83310.25810.4
0.2811 0.50.407 00001 0.134 1 0.976 1 0.83301 0.5
According to entropy method, the weights of different indices were calculated.
Evaluation Results
After normalization and weights’ determination, the final matrix Y is as following,
( )
4 18
ij j
Yy Y
= =
( )
4 18
is the matrix after normalization; ωj means weights of different indices.
00.016000.043 0.048 0.065 0.032 0.009000000.0010.0160.042 0.028
0.03400.06 0.0310.040 0.040 0.017 0.04700.071 0.038 0.046 0.028 0.0780.017000.031
0.045 0.02500.056 0.058 0.072 0.025 0.022 0.035 0.029 0.032 0.072 0.039 0.065
0.065 0.016 0.042 0.012
0.013 0.039 0.03 0.02300000.046 0.009 0.047 0.070 0.042 0.06500.064 0.0210
After normalization, the value of 18 indices all belonged to
interval [0, 1]. The maximum was the best. Therefore, the ideal program
should be composed of the maximum value of
each index as follows,
( )
0.045 0.039 0.060.056 0.058 0.072 0.0650.047 0.046 0.0710.0470.072 0.039 0.0780.0650.064 0.042 0.031
( )
0.634 0.437 0.3540.523
( )
0.202 0.1560.1210.170
Therefore, the evaluation of soil and water conservation ca-
pacity of LS is the minimum, that of CP is the maximum. The
second one is CPS, followed by LSC.
Conclusion and Suggestion
Soil and water conservation is one of the most important tar-
gets of eco-environment construction in Southern China. We
found that under the same condition, soil and water conserva-
tion capacity of hardwood forest is better than that of mixed
forest of hardwood and softwood, and much better than that of
conifer forest.
According to the sensitivity analysis, it showed that hard-
wood LS has the best soil and water conservation capacity
among the others. Therefore, the mixed broadleaf forest of
robur and Chinese gugertree should be the first choice when we
implement the returning farmland to forestpolicy in the
Three Gorges area.
It also showed that the soil and water conservation capacity
of CP is difficult to improve over a short time from now.
However, the soil and water conservation capacity of LS, LSC,
and CPS can be improved by taking proper managing practices.
Litter and soil layer under the forest play a very important
role in protecting soil and water. Improving the soil properties
should be taken to enhance the soil and water conservation
capacity of these plantations.
That proves that ideal point method is suitable for evaluating
forest soil and water conservation capacity. Using the ideal
point method to evaluate the capacity of soil and water conser-
vation of different forest types can avoid long-time processing
measurement, but with more objective and precise results.
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