Extreme weather conditions, namely droughts, heat waves, heavy rains, floods, and landslides are becoming more frequent globally and in Serbia as a result of climate change. Generally, various parts of human society are affected by changing climate conditions. Forest ecosystems are one of the most sensitive systems to weather and climate. In that sense, small changes may lead to large disturbances including forest decline, outbreaks of insect pests and diseases and eventually mortality. In Serbia, the average temperature in forest ecosystems of the most important and abundant forest tree species has risen for more than 1°C in the last thirty years (1990-2019) in comparison to the previous period (1961-1990). During the last thirty years, the northern and western parts of Serbia experienced an increase in precipitation as opposed to the southern and eastern parts of the country. If one takes a closer look at the climate within a particular forest stands, it would seem that the effect of precipitation decrease is stronger in less humid parts of a tree species range. In this paper, we discuss various aspects of climate change impacts on forests and forestry, including forest ecology, genetics, physiology, pests and diseases, ground vegetation, monitoring, reporting and verification system, climate change litigation and perspectives of forests in the 21st century in Serbia.

Republic of Srpska (RS) covers an area of 24,666 km 2 or about 48.5% of Bosnia and Herzegovina's territory. Spatial and environmental changes accelerated due to dynamic historical period upon the RS formation and the following development period. The extent of these changes can be determined by comparing satellite images obtained from different acquisition periods. By processing images, with the support of geographic information systems, it is possible to create a database that aims to analyze spatial processes in a specific area in order to determine quantitative and qualitative parameters. In this way, the trends of spatial development (e.g. excessive logging, land cover damage, water pollution, etc.) and potentially vulnerable components of the environment can be monitored. The data for Bosnia and Herzegovina were collected from CORINE Land Cover (CLC) database for 39 European countries. The CLC is a project launched by the European Environment Agency (EEA) more than thirty years ago with the aim of collecting, coordinating and ensuring the consistency of information on natural resources and the environment. The goal of the paper is to identify land cover types and determine environment changes in the territory of Republic of Srpska over the period 2000-2018 as a consequence of the land use conversion.

Many studies have shown that small climate changes can strongly affect the forest trees growth rate, many times causing changes in species habitats. In general, drought is mentioned as the main problem, so it is necessary to carry out its identification and quantification to investigate its effects on forests in Republic of Srpska. This study aims to analyse the relationship between the growth of European beech (Fagus sylvatica L.) at optimal altitudes in the Republic of Srpska and its climate characteristics represented by the Forestry Aridity Index (FAI) and Ellenberg's climate quotient (EQ) for 1950-2015 timespan. FAI and EQ were calculated using climate data (temperature and precipitation) extracted from a gridded dataset (E-OBS). Sampling was carried out in two localities near Vlasenica and Mrkonjić Grad at 1050 and 1030 meters above sea level (m a.s.l.), sampling the cores from 15 dominant trees at each locality. Using the Pearson Correlation Analysis, a negative impact on tree rings width (TRW) with rising index values was identified. This is especially pronounced for the index values of the year prior to the ring formation. In general, stronger negative correlations between TRW and EQ are found for the locality near Mrkonjić Grad, while FAI index showed a greater negative impact on TRW for the locality near Vlasenica.

As forests in Bosnia and Herzegovina cover 2,904,600 ha or 56.7 % of its total area, and since the meteorological data analysis for the period 1961–2014 shows that the mean annual temperature maintains a continuous rise, сlose attention should be paid to these fragile ecosystems. It is important to note that one of the most economically valuable species for forestry in Bosnia and Herzegovina, Norway spruce, is particularly endangered due to its very low drought resistance and spread of various diseases. Comparing the last climate sequence (1991–2019) with the previous one (1961–1990) we found that the spruce-inhabited areas showed an average increase in the values of the Forest Aridity Index of 0.929. As for the Ellenberg’s climate quotient, it is noticeable that climate change is not as strong as in the case of the Forest Aridity Index. Based on projections for the mid- (2041–2070) and late-century (2071–2100) under the RCP 4.5, there will be no change that is likely to significantly affect the distribution of spruce. The predicted rates of decline and altitudinal shifts of favorable habitats are negligible. On the contrary, projections under the RCP 8.5 predict a significant reduction of suitable habitats, both for the existing range of Norway spruce and the entire territory of Bosnia and Herzegovina. Particularly, late-century projection under the RCP 8.5 predicts an almost complete reduction of suitable habitats, while small areas of suitable habitats at higher elevations will remain intact.

The analysis of data from the first two decades of the 21st century shows that the area under forests in Bosnia and Herzegovina is gradually decreasing. In order to gain a detailed insight into this process, the paper will analyse the forest databases of the European satellite monitoring program Copernicus. This program, among other things, monitors the condition of forests in 39 European countries by using the High Resolution Layer (HRL). The HRL Forests database consists of 3 types of (status) products, and additional change products. The status products are available for the reference years 2012, 2015, and 2018. The status layers provide information on the Dominant Leaf Type and the Tree Cover Density at pixel level for the reference year 2018 in 10 m resolution. The Forest Type layer largely follows the Food and Agriculture Organization (FAO) forest definition. Also, the paper will use the data on forests from the CORINE Land Cover project for 2000, 2006, 2012 and 2018. The time-series includes a land change layer, highlighting changes in land cover and land use. The CLC Changes database will be analysed separately for three periods: 2000-2006, 2006-2012 and 2012-2018, due to more accurate data on forest losses. The results of the research show that forests in Bosnia and Herzegovina were reduced by 2.95%, in the period 2012-2018, where 2.55% of them were coniferous. Forests are primarily endangered by the process of conversion to transitional forest / shrub and fires.