462 Modern Agricultural Reforms
grows. On the low mountains and hills cash tree crops such as chestnut, tung oil
trees, Moso bamboo (Phyllostachys pubescens), Chinese sapium, tea trees, lacquer
trees and citrus are cultivated. But warm-temperature fruit trees such as persim-
mons, Chinese chestnuts, pears, peaches and apricots can also be grown in this
region. During recent decades many species have been used for afforestation.
Besides the endemic species such as Chinese fir, masson pine and Metasequoia
glyptostroboides, moso bamboo, Quercus accutissima, Cinnamomum camphora,
Castanopsis fargessi and Sassafras tzumu, as well as many other fast-growing species
such as Pinus elliottii, Pinus taeda, Chamaecyperis, spp. and Eucalyptus spp. have
been introduced for afforestation.
In the lower reaches of the Yangtze River are vast low-lying plains. The zonal
vegetation is mixed evergreen and deciduous broad-leaved forest, and the zonal soil
type is yellowish-brown soil, restricted to low mountains and hills. The extensive
plains have been turned into cultivated vegetation and paddy soil. Even on low
mountains and hills, original mixed forests were mostly destroyed and have been
substituted by secondary growth of shrubs and grasses, and partly planted with
masson pine and other economically valuable tree crops, such as tea and fruit trees.
The great contrast between the intensively used and densely populated plains and
the rather extensively used and sparsely populated slope lands is an outstanding
feature of the region.
Main environmental problems
Degradation of forest
The long history of exploitation, increasing population pressure, the demand for
timber and fuelwood, inadequate forest management, illegal use of marginal land,
and poor economic development of the region, have led to declining forest cover
and timber stocks. For instance, in Sichuan Province, forest cover decreased from
20 per cent in the 1950s to 13 per cent in the 1980s. While forest cover in the
Sichuan Basin accounts for only 4 per cent. A similar situation is found in other
provinces along the river; in Jiangsu, Anhui and Guizhou Provinces forest cover is
only 8 per cent, 13.5 per cent and 15.1 per cent, respectively. So, the water conser-
vation and regulatory role of forests in the Yangtze River has decreased signifi-
cantly.
Degradation of forest quality has also occurred. Many forests in the region are
being degraded into low-value, secondary forest through repeated human distur-
bance, low soil fertility and careless management. In the upper reaches of the Yang-
tze River there are over 600,000ha of low-value forest, most of them in the Jialing
River area and accounting for 60 per cent of the total forest. Pine and cypress are
the dominant species of low-value forests (Yang Yupo, 1993). It is an arduous task
to improve the current situation of low-value forests and replace them by high-
yield forests with effective environmental protection.