Abstract:
Tropical deforestation and degradation and climate change are highly discussing
contemporary phenomena of the globe. Investigating the temporal and spatial
variation of deforestation, degradation, climate and interrelationship of the
mentioned variables in the intermediate zone in Sri Lanka, which have been
regarded lightly in research so far, are the objectives of this paper. Land use change
over 56 years was investigated at the district level in the intermediate zone by using
Land matrix tool. In order to identify the climate change over 56 years, rainfall,
temperature and wind speed were selected as climatic variables and temporal
change was detected by time series and spatial changes by kriging analysis. During
the period of 1956 to 1981 extent of forest cover has declined by 3% and 54% in
Badulla and Monaragala districts where deforestation rates were 48% and 19%
respectively during the period of 1981 to 2012. Main contributors to deforestation
common to study area were Chena cultivation, home gardens and paddy cultivation.
Home gardens and paddy cultivation have increased in every district throughout
the time especially within the 50m buffer zone from a dense forest. Proximity
analysis identified that low and mid-country had the highest closeness for the above
two land uses. Eastern and southeastern part of the intermediate zone had received
the highest amount of mean rainfall while it had declined in the northwestern
direction. Highest mean rainfall amount was received from second inter-monsoon
and the lowest from southwest monsoon during which the amount of rainfall
decreased by 0.64mm per year. Nevertheless, northeast monsoon rainfall growth
was by 1.74mm per year. The average maximum temperature in the intermediate
zone had a positive linear trend that contained a rise in temperature of 0.008 Co per
year. When considering the overall trend of temperature in the intermediate zone,
the maximum had a gradual growth trend while the minimum had a declining trend
in a geometric manner. Low country (2.8 km/h) showed a prevailing wind with a
speed higher than that in the mid country where both recorded high flows in the
evenings. The impact of forest cover change on climate variables such as rainfall
(p=0.042) and wind (p=0.001) was identified. Further investigation, adopting new
methods, is needed on this matter.
