摘 要(英文)：Dinghushan biosphere reserve (112°30′39″- 112°33′41″E , 23°09′21″- 23°11′30″N) is located in
central Guangdong Province in southern China , about 84 km from Guangzhou city , with an area of 1 156
hm2 . Due to its location on the tropic of cancer , the forest vegetation is very rich and dominated by monsoon
evergreen broad-leaved forests. The dominant forest types in the Dinghushan biosphere reserve are Pinus mas2
soniana forests (PF) , mixed Pinus massoniana/ broad-leaved forests (PBF) , and monsoon evergreen broadleaved
forests (MBF) , which form a natural successional sequence. The aim of this paper was to quantify the
magnitude and annual variation of water yields in the Dinghushan Nature Reserve in the three forest types ,
which would be used for estimating carbon outputs in streamflow , and to discuss how hydrological processes
vary at different successional stages of forest development.
Climatic data were obtained from weather stations located at the Dinghushan Forest Ecosystem Research
Station , Chinese Ecosystem Research Network (CERN) . Runoff was monitored at three landscape levels. The
first level was the entire eastern watershed. The second level referred to small catchments within the larger wa2
tershed that were dominated by the different forest types , i. e. , a PF catchment , a PBF catchment , and a
MBF catchment. The third level referred to three surface runoff plots placed within each of the three catch2
ments. Stream runoff in the eastern watershed and the three smaller catchments was monitored continuously
year a round by measurement weirs with streamflow recorders. The ephemeral surface runoff from the nine
surface runoff plots was collected in separate plastic tanks and the water level of each tank was recorded auto2
matically following every precipitation event. The subsurface water table depth was recorded manually at 5- day intervals in wells located in the valley of the eastern watershed at elevations of 20 - 30 m. Soil water content
has been measured monthly using neutron probes since 1983. Soil water content was measured at 10 - 15
places in each of the three catchments and distributed across the elevational gradient. At each point , the water
content was monitored at three soil depths , 0 - 15 , 15 - 30 and 30 - 45 cm. Throughfall was collected at four
sites in each catchment using cross- shaped troughs with a horizontal area of 2. 25 m2 , and was measured using
a fluviograph (Zhou , 1997) . Thirty trees adjacent to each throughfall site that represented the range of species
and size of trees in each catchment were selected and stemflow monitored (Gash et al . , 1978) . Stemflow was
collected in an open PVC tube wrapped around the stem of each tree that led to a tipping bucket rain gauge.
Throughfall and stemflow were monitored from April 1999 to April 2000 , during which time there were 61
rain events. Leaf area index and canopy cover were measured at 10 sampling sites within each catchment four
times each year using a CI-110 digital plant canopy imager (CID , Inc. Vancouver) .
The water yield in the eastern watershed of Dinghushan biosphere reserve was 66. 5 %of its rainfall with
the maximum outflow occurring about one day after a rain event. The subsurface water table averaged 2. 22 m
below the soil surface , with the deepest water levels at 2. 84 m and highest at 1. 14 m depth. The annual aver2
age position was 2. 38 , 2. 27 , 2. 08 , 2. 13 and 2. 11 m deep in the years 1999 , 2000 , 2001 , 2002 and 2003 ,
respectively. The depth of the water table in the eastern watershed was correlated with rainfall events that oc2
curred 16 days previously. There was an abating tendency of soil water content for all the three forest commu2
nities. The tendency was statistically significant for MBF ( p < 0. 01) and PBF ( p < 0. 05) , whereas no sta2
tistically significant effect for the PF was found.
The relationship between the amount of throughfall and precipitation was linear for the three dif2
ferent forest communities at different successional stages , but the correlation decreased f rom MBF ,
PBF uo PF. The ratio of throughfall to precipitation also decreased with successional stage of the for2
est , f rom 83. 4 % , 68. 3 % to 59. 9 % for the PF , PBF and MBF , respectively. The relationship of
stem flow with DBH was cont rolled by the effect s of the whole forest community instead of a single
species. The canopy st ructure of the forest community played a key role in the redist ribution of precipi2
tation. The canopy interception rate in the MBF was 83. 3 % in February when total precipitation was
28. 7 mm , but was only 18. 9 % when precipitation was 297. 8 mm in J une. The canopy interception
rate increased in the three forest types f rom PF , PBF to MBF.
鼎湖山地带性植被及其不同演替阶段水文学过程长期对比研究