Climate Change Effects on Southern Subtropical and Tropical Tree Species in Ganzhou City, China

Aims: To confirm climate warming changes that have taken place in Gannan Arboretum and Ganzhou City by the expect success of introduced tropical tree species as a response to climatic warming scenarios.
Study Design: Cross-sectional study.
Study Site and Duration: Survey and observational sites were located in 1) Gannan Arboretum and 2) Ganzhou City, Jiangxi Province, China. The survey and observations of introduced tree species were conducted from October, 2009, to November, 2010. Additional growth records were obtained for a period prior to and including the 1970s to assist in the investigation.
Methodology: 1) The meteorological data (1951–2009) record was used to analyse climatic change patterns. 2) Growth and development of introduced tree species were examined to evaluate effects of introduction. 3) Climate zone attributes of introduced tree species were determined in order to establish place of origin. Effects of introduced tree species were coupled with climatic change scenario data to analyze associative relationships.
Results: 1) A trend in climate warming has been evident in Ganzhou City since the1950s. Based on metrological records from 1951 to 2009, a steady rise in annual average temperature has occurred in the region, increasing from 0.2ºC to 0.3ºC each 20 year period. This trend has been especially evident by changes to average temperature during the coldest month (January) as well as changes in annual minimum temperatures. 2) According to observations and measurements, 39 introduced tropical tree species have successfully established themselves in the Ganzhou region through natural domestication. Among these, 24 tree species were considered basically successful with normal growth patterns while the remaining 15 species achieved preliminary success. 3) Stem analysis data on the five primary introduced tree species indicate that growth patterns were normal and vigorous, suggesting that these tropical tree species have successfully established themselves. It was therefore determined that the successful northward migration of the 39 tree species investigated was chiefly the result of a climate warming trend taking place in the region.