Abstract:
We present the first multi-year long time series
of local climate data in the seasonally dry tropical forest in
Southern Ecuador and related growth dynamics of Loxopterygium
huasango, a deciduous tree species. Local climate
was investigated by installing an automatically
weather station in 2007 and the daily tree growth variability
was measured with high-resolution point dendrometers.
The climatic impact on growth behaviour was
evaluated. Hydro-climatic variables, like precipitation and
relative humidity, were the most important factors for
controlling tree growth. Changes in rainwater input affected
radial increment rates and daily amplitudes of stem
diameter variations within the study period from 2009 to
2013. El Nin˜o Southern Oscillation (ENSO) related
variations of tropical Pacific Ocean sea surface temperatures
influenced the trees’ increment rates. Average radial
increments showed high inter-annual (up to 7.89 mm) and
inter-individual (up to 3.88 mm) variations. Daily amplitudes
of stem diameter variations differed strongly between
the two extreme years 2009 (wet) and 2011 (dry). Contrary
to 2009, the La Nin˜a drought in 2011 caused a rapid
reduction of the daily amplitudes, indicating a total cessation
(‘growth collapse’) of stem increment under ENSOrelated
drought conditions and demonstrating the high
impact of climatic extreme events on carbon sequestration
of the dry tropical forest ecosystem.
