In the last decades, after hot waves and long dry periods without rain, in many countries is seen massive woodland drying . Researches show that this pathological process is not only due to the bad climate conditions, but is also connected with another biotic factors.
In 2016 Science for Nature made a pilot research about the health of the trees in a forest region in Rila mountain.
The research uses combination between classic and inovative methods for thees health condition assessment, like:
- microscopic analysis (external signs);
- microscopic analysis (determination of species or genus of the pest);
- dendrochronological analysis (collecting information from the annual rings in the wood);
- capturing and mapping with the drone (for optimal precision in assessing big trees health conditions like spruces);
- making a geographic informational system
The results from the research show 3 main stress periods in their lives. The first starts in 1913 and ends in 1931. The secound is in the years between 1941 and 1948. The third stress period, which is the longest, is after 1985 г. and with few exceptions – to 2016 г. The climate conditions (temperature, moisture) are main growing factors for the forests. The average temperatures in June are optimal for growing and undoubtedly the most negative impact on it have the temperatures in September.
In this area are presented the following pathogenes:
- Melampsorella caryophyllacearum;
- Heterobasidion annosum;
- Armillaria ostoyae;
- Insects like: Ips typographus, Pityokteines curvidens