Vertical climate zones in Biga peninsula: The impact of climate change and air pollution on forests

Abstract

Biga Peninsula is situated in between Marmara Sea and Aegean Sea. The peninsula consists of the hilly and mountainous mass between Biga and Çan on North, Kaz Mountains on South, and Koca Çay Basin lying in between those two masses. The northern oriented slopes of the peninsula are under the influence of "Marmara climate", which originates from Black Sea region and is cool and humid. The western part of the peninsula is cooler due to the northern winds passing through the Dardanelles. The slopes oriented towards Aegean Sea are under the influence of Mediterranean climate which is warm and humid (arid in summers). These distinct climate characteristics combined with the changes in altitude at various areas lead to unique vertical climate zones in Biga Peninsula. The composition of forests in Biga Peninsula reflects the features of vertical climate zones. While the northern forests show more variation; olive, Calabrian Pine (Pinus brutia) and Black Pine (Pinus nigra) dominate the southern species. Northern Biga Peninsula is under the direct impact of the air pollution by Istanbul and Marmara Region as well as countries situated on the north and west of Black Sea. Meanwhile, south of the peninsula is exposed to the pollution caused by the Soma thermal plant, and recently by the Çan thermal plant as well as the settlement areas (for heating purposes). Regardless of the source of the air pollution, the sulphur content on the needles of Calabrian Pines, black pines and fir trees (Abies equitrojani) were found to be above the toleration limit of chlorophyllous cells in the entirety of the peninsula. Such an impact results in premature defoliation of the old needles, diminished wood production and narrowing of the annual tree rings. As a result of the air pollution, increasing CO2 rate in the atmosphere has caused a tangible warming particularly increased during summer. Increased CO2 causes aridification. The data gathered from 4 meteorology stations within the vicinity of Biga Peninsula supports this notion and has been associated with a change in the limits of vertical climate zones. Upward migration of vertical climate zones ranges between 50 and 100 meters depending on the exposition and slope of the land and the season. While the industrialization in the areas surrounding the region dates back to late 19th century, it is not clear if there has been sufficient time for this migration to cause substantial impact on the growth and expansion characteristics of local plant species. Data from our previous work on animals such as "pine processionary caterpillar", on the other hand supports this hypothesis by a change in its breeding pattern on the Calabrian pine (Pinus brutia) zone instead of black pine (Pinus nigra) zone. This study aims to investigate the impact of the air pollution on needles of the coniferous trees in Biga Peninsula and the link to the migration of vertical climate zones. © 2011 Published by Elsevier Ltd.