PS 14-105
Phenological characteristics of an endangered tree species - Abies ziyuanensis
Abies ziyuanensis L. K. Fu et S. L. Mo is a native, rare and highly endangered tree species in China. Recently, a few isolated A. ziyuanensis communities have been discovered in the Nangling mountain areas in subtropical China with a total of about 600 individuals remaining. Because of the features of poor natural regeneration, production of seed at long interval, low germination rate and extremely small remaining population size, A. ziyuanensis has been classified into the first class national keynote protected wild plant species in China since 1994 and is known as a ‘living fossil plant species’. In this study, the phenological characteristics of eight A. ziyuanensis individual trees were investigated in Yanling county of Hunan province, China. The eight individual trees included 3 young individuals (6-year old growth), 3 mid-aged individuals (18-year old growth) and 2 matured individuals (45-year old growth), The processes of sap flow starting and ceasing, bud break, leaf expansion and leaf growth were observed and measured. The microclimate variables surrounding the individual trees were recorded during the growth phases of the species. The relationships between the phenological characteristics of A. ziyuanensis and microclimatic variables were developed.
Results/Conclusions
The results showed that sap flow from A. ziyuanensis was temperature dependent and the sap did not start to flow until the mean daily air temperature was higher than 80C. A. ziyuanensis showed bud break when the mean daily air temperature reached 110C, soil temperature on the floor was 150C, and the relative humidity was larger than 93%. Annual growing period of A. ziyuanensis was relatively short and was about 80 days with about fast-growth times of 40-50 days. The growing season occurred in the months of May and June and the optimum daily mean temperature for its growth was 16-190C with a day-night temperature difference of 8-100C. The flower bloomed in April and there were few female flowers within the fructification in the lower part of the canopy compared to the male flowers. The blossom of female flowers was found only near the top of the canopy or/and some tips of strong branches, which greatly affected the seed production of the species. Our results suggested that this tree species could be introduced to the hill regions as a plantation species. The study provided important scientific basis and reference for conservation of the endangered A. ziyuanensis species.