Fast economic development in China has resulted in a significant increase in energy demand. Coal accounts for 70% of China＇s primary energy consumption and its combustion has caused many environmental and health problems. Energy security and environmental protection requirements are the main drivers for renewable energy development in China. Small farmland and food security make bioenergy derived from corn or sugarcane unacceptable to China： the focus should be on generating bioenergy from lignocellulosic feedstock sources. As China cannot afford biomass energy production from its croplands, marginal lands may play an important role in biomass energy production. Although on a small scale, marginal land has already been used for various purposes. It is estimated that some 45 million hm2 of marginal land could be brought into high potential biomass energy production. For the success of such an initiative, it will likely be necessary to develop multipurpose plants. A case study, carried out on marginal land in Ningnan County, Sichuan Province with per capita cropland of 0.07 ha, indicated that some 380 000 tons of dry biomass could be produced each year from annual pruning of mulberry trees. This study supports the feasibility of producing large quantities of biomass from marginal land sources.
This paper reports the first population ecology study of the endangered Magnolia sargentiana Rehder ＆ Wilson （Magnoliaceae）. Magnolia sargentiana is a protected species in China, but little is known about its present status in the field. In 2007 and 2008, we surveyed the population and conservation status ofM. sargentiana in the Provincial Mamize Nature Reserve and the National Meigu Dafengding Nature Reserve, Sichuan Province, southwestern China. Natural regeneration is poor because of unfavorable environmental conditions and anthropogenic disturbances. Flower buds and bark ofM. sargentiana are used in traditional Chinese medicine and their collection by local people over the period 1983-1994 has led to marked population declines. The collection of flower buds and bark is now banned, but hewing branches for firewood and grazing continues to have a negative impact on the recovery of M. sargentiana populations. To protect the species, we require a ban on hewing branches, closure of primary forests to reduce the impact of humans and ungulates, better education of local people, and increased awareness of wildlife conservation.
