Influence of climate on tree mortality in taiwania (Taiwania cryptomerioides) stands in Taiwan

Abstract

Abstract Background Taiwania (Taiwania cryptomerioides Hayata) is a relict tree species found mainly in Taiwan, with smaller populations in China, Vietnam, and Myanmar. Taiwania is considered to be vulnerable to extinction. The objective of this research was to develop a model to predict the mortality of taiwania from climate and other mensurational variables. Methods The mensuration, mortality, and climate data came from permanent sample plots established as thinning experiments and a nearby climate station. The data were analysed using logistic regression with individual tree mortality as the response variable. Results The important predictor variables of mortality were social status [defined as diameter at breast height (dbh) divided by average dbh] and annual precipitation in the year of death. The probability of mortality increased as social status decreased and as annual precipitation increased. The positive correlation between mortality and precipitation is likely a consequence of typhoons since precipitation and mortality caused by wind throw both result from typhoons. Conclusions Climate change could increase the number and severity of typhoons occurring in Taiwan. This may increase the mortality rate of taiwania, which would detrimentally affect the viability of taiwania populations.

Keywords

• Climate change
• Logistic regression
• Precipitation
• Self-thinning
• Typhoon