Assessment of the potential of Pinus radiata for ecological restoration of the Yangtze River catchment in Aba Prefecture, Sichuan, China

FST/2001/086: Assessment of the potential of Pinus radiata for ecological restoration of the Yangtze River catchment in Aba Prefecture, Sichuan, China

China

State Forests of New South Wales, Australia

Dr Hui-quan Bi
Phone: 02 9872 0168
Fax: 02 9871 6941
Email: huiquanb@sf.nsw.gov.au

• Chinese Academy of Forestry, China
• Sichuan Forestry Academy, China
• Aba Forest Research Institute, China

$150,090

01/07/2002 - 30/06/2004

01/07/2004 - 30/06/2007

Dr Russell Haines

Severe erosion has contributed to massive flooding and excessive sedimentation on a number of catchments in China, particularly the upper catchment of the Yangtze River in Sichuan. Due to the extreme site degradation and the harsh, dry climate of much of the upper Yangtze catchment re-establishment of the natural forest and native species has been problematic, and the Chinese have tested a range of exotic tree species for their suitability as protection forests. Pinus radiata, a conifer widely used in Australia in commercial plantation, holds promise.

This project deployed Australian experts, in collaboration with Chinese scientists, to aid the introduction and testing of a better range of P. radiata germplasm in the Yangtze catchment. The biological risks of establishing the species in such a new environment were assessed, and the project team developed nursery, field and data management technologies to support the large expansion of plantings planned for P. radiata.

The project team assessed the forest health risks to the long term success of P. radiata introduction in Aba. A forest health monitoring program was put in place as a part of continuing evaluation of forest health risks to the long-term success of P. radiata introduction. Forest health survey and assessments were conducted twice for the widely separated small plantations established for environmental purposes. Presence of pest and pathogen species and their levels of infestation were recorded to evaluate the gradual loading of indigenous pests and diseases onto the newly introduced exotic species and to detect earlier signs of a pest and disease attack.

At the same time, the forest health literature on P. radiata and other Pinus species in China was reviewed to identify both indigenous and exotic pathogens and pests that could pose a threat to the long-term success of P. radiata introduction. The scientists surveyed the full text of scientific papers, published and unpublished reports from various sources and examined historical records of pest and disease outbreaks in the coniferous forests of Aba prefecture and those of past forest health surveys. More information was gathered from personal communications with other forest health experts.

This broad forest health literature and information review served as a good basis for the assessment of risks to forest health in relation to the long-term success of the species introduction in the dry river valley area. The scientists drew up a list of potentially threatening indigenous and exotic pathogens and pests; for each species on the list they rated as low, medium or high the likelihood of an attack and the impact of the possible attack.

The scientists also integrated site, climatic information and knowledge on growth performances elsewhere in the world through climate modelling to identify suitable areas for environmental plantings of P. radiata - in southwest China in general and in the dry rive valley area in particular. Their work led to a paper in the international journal Forest Ecology and Management, describing a new climatic profile for P. radiata that identifies summer rainfall areas in southwest China potentially suitable for environmental planting of the species on degraded lands to reduce soil erosion.

This profile delineates the climatic requirements of P. radiata through six climatic factors - including the absolute minimum temperature as a measure of frost risk in the continental climatic environment. It also defines lower temperature and rainfall limits than profiles previously developed for commercial plantations. Areas with climatic conditions that match the new climatic profile were mapped using ArcInfo GIS. At the national scale, a climatically suitable area of more than 266,000 km2 across three provinces in southwest China was identified. Mean maximum temperature of the hottest month and the length of dry season appeared to be the major factors limiting the spatial extent of matched areas at this broad scale.

The results of climate matching for the Minjiang dry valley area in particular correspond well with the growth performance of experimental plantings in the field. At this regional scale, mean annual precipitation and mean minimum temperature of the coldest month are the major factors constraining the spatial extent of climatically suitable areas. The mapped areas can help define the working limits and serve as indicative zones for environmental plantings of P. radiata aimed at reducing soil erosion in southwest China. They will also enhance understanding of the fundamental climatic niche and the potential geographical range of P. radiata.

A provenance experiment was successfully established over three sites in 2004-05 and remains under surveillance for potential pest and disease problems as a part of the forest health monitoring program.