Friday, August 6, 2010

PS 93-43: Effects of manipulative precipitation change and nitrogen addition on morphological traits, biomass and biomass allocation of five tree seedlings in Gutian Mountain of Zhejiang, China

Shouren Zhang, Qian Wu, Jia Ding, and Hui Yan. Institute of Botany, Chinese Academy of Sciences

Background/Question/Methods

To study the effects of precipitation change and nitrogen deposition on morphological traits and growth of China's subtropical evergreen broad-leaved forest, we set up a controlled-experiment in Gutian Mountain of Zhejiang province in China with two factors: 1) nitrogen (control and nitrogen addition with dose of 10 g m-2 yearly) and 2) precipitation (natural precipitation as control and reduction of 30 %). We periodically investigated the tree species’ traits of morphology, biomass and their allocation in the following three years.

Results/Conclusions

The results were shown that  1) nitrogen significantly promoted the growth in height , stem basal diameter and biomass of Elaeocarpus sylvestris(Lour.)Poir, Liquidamba formosana and Schima superba, but only increase branch and leaf biomass of Pinus massoniana and branches of Cyclobalanopsis glauca; 2) after two years’ treatment, nitrogen increased leaf weight ratio of S . superba and E . sylvestris , also increased branch weight ratio of L . formosana and C . glauca, decreased leaf weight ratio of C . glauca. With extension of the treatments to theer years, nnitrogen increased stem weight ratio of E . sylvestris, L . formosana and S . superba and branch weight ratio of P . massoniana and C . glauca. The increase of the aboveground weight ratio is at the cost of the decrease of underground weight ratio. Nitrogen reduced the root weight ratio of C . glauca ,S . superba,L . formosana and E . sylvestris; 3) Reducing precipitation through three years significantly promoted the growth in stem base diameter and whole plant biomass of L .formosana, increasing its root weight ratio and root/shoot ratio, reducing its leaf weight ratio.