Understanding Past and Predicting Future Climate Changing Scenarios through Tree Rings in Oak Forest Region of Khyber Pakhtunkhwa, Pakistan

Abstract

The Earth's climate system exhibits variability in temperature and rainfall, among other factors. However, existing weather station and satellite observations are too short or sparse to capture this variability fully. To address this limitation, we used tree rings to archive information about past environmental conditions. Tree rings are formed based on various physical, biochemical, and environmental conditions present during the year they were formed, making them a valuable tool for understanding long-term climate variability. They provide a detailed record of environmental conditions, such as temperature, precipitation, and drought, over the lifetime of the tree. This information can be used to reconstruct historical climate patterns and understand how they have changed over time. Tree rings are formed when a tree grows a new layer of wood each year. Various environmental factors, such as temperature, precipitation, drought, and sunlight, can influence the width and characteristics of these rings. The study focused on understanding past and predicting future climate-changing scenarios in the mountainous by using the most common and straightforward measurement of the width of the annual ring, which reflects variability in the factors responsible for annual growth. The rainfall pattern and temperature fluctuations in the region have been found to exhibit a complex relationship. The rainfall pattern has shown variations, and the temperature has experienced increases during specific periods. We observed an increase in the frequency of droughts and flooding events in the study area. Tree rings from Malam Jabba showed the highest rainfall decline in the late 1990s, while an increase was observed in Miandam, Kalam, and its upper mountains. Similarly, we noted moderate to extreme droughts in the years 1918 to 1935, and then in the years 1960 to 1965, 1987, and then with some intervals, i.e., 2014 to 2018, both in lower and upper Swat regions. The analysis of tree rings has revealed a significant positive trend in the magnitude of maximum annual and seasonal temperatures in both the upper and lower regions of Swat, particularly during the late winter and early summer periods. This trend was observed to be most pronounced during the 1950s and 1960s.