Impacts of long-term elevation of atmospheric carbon dioxide concentration and temperature on the establishment, growth and mortality of boreal Scots pine branches.

摘要

The aim of this study was to investigate the impacts of elevated carbon dioxide (CO2) and temperature on the establishment, growth and mortality of the branches of Scots pine (Pinus sylvestris L). In 1997, 16 young trees were individually enclosed in chambers, in eastern Finland, for a period of 5 years (1997-2001), in an environment that simulated the future climate for the region. There were four replicates of each treatment, including combinations of ambient and elevated CO2 and temperature. Measurements were carried out on the establishment of new branches, branch diameter growth and branch mortality. Elevated temperature and elevated CO2 had no positive effect on the number of branches that established each year or branch diameter growth. They were, instead, related to tree height growth and stem diameter growth, respectively. However, elevated CO2 and temperature caused an increase in branch mortality..