INTEGRATED EFFECT OF METEOROLOGY, AIR POLLUTION AND SURFACE OZONE ON CROWN CONDITION AND STEM INCREMENT OF SCOTS PINE TREES UNDER DIFFERENT SITE CONDITIONS

Abstract

Adaptation of the local tree species to recent environmental conditions rather often is found to be very low even when it affects tree health integrally with air pollutants, and surface ozone. The aim of the study was to quantify the relationships between environmental factors, annual stem basal area increment and crown defoliation of Scots pine trees located in the north-eastern part of Lithuania. The obtained data revealed that Scots pine is the most sensitive species to environmental changes. Its reaction to both negative and favorable environmental factors was best expressed, what indicated its highest level of resilience and adaptive capacity to recent global changes. Air concentrations of sulphur species and ammonium as well as their deposition were the main drivers resulting in changes in mean defoliation of Scots pine trees in Lithuania. The data on stem basal area increment collected on two different forest sites (FS): mineral olygotrophic and organic mesoeutrophic soils confirmed that since the 1980 growing season the annual increment of the pine trees has increased. The causes of this rapid growth were as follows: higher air temperatures during the dormant period and, to a lower extent, the higher temperatures from May through August. The effect of precipitation was negligible. During vegetation nitrate deposition as fertilizing compound stimulated the pine tree stem BAI formation especially on mineral soil FS. Negative ozone effect on pine growth intensity was significant for pine trees on mineral soil FS. Higher moisture regime significantly increased the tolerance of pine trees to the negative effect of air concentration of acidifying compounds, their wet deposition and surface ozone. The study is based on the results obtained conducting national project supported by Lithuanian Council of Research “FOREstRESS” (SIT- 3/2015).

Keywords: Scots pine, defoliation, stem basal area, meteorology, acidifying compounds, ozone

Article DOI: http://doi.org/10.15544/RD.2017.174