Vitas Marozas

Sensitivity of Beech Trees to Global Environmental Changes at Most North-Eastern Latitude of Their Occurrence in Europe

The present study aimed to detect sensitivity of beech trees (Fagus sylvatica L.) to meteorological parameters and air pollution by acidifying species as well as to surface ozone outside their north-eastern distribution range. Data set since 1981 of Preila EMEP station enabled to establish that hot Summers, cold dormant, and dry and cold first-half of vegetation periods resulted in beech tree growth reduction. These meteorological parameters explained 57% variation in beech tree ring widths. Acidifying species had no significant effect on beech tree growth. Only ozone was among key factors contributing to beech stand productivity. Phytotoxic effect of this pollutant increased explanation rate of beech tree ring variation by 18%, that is, up to 75%. However, due to climate changes the warmer dormant periods alone are not the basis ensuring favourable conditions for beech tree growth. Increase in air temperature in June-August and decrease in precipitation amount in the first half of vegetation period should result in beech tree radial increment reduction. Despite the fact that phytotoxic effect of surface ozone should not increase due to stabilization in its concentration, it is rather problematic to expect better environmental conditions for beech tree growth at northern latitude of their pervasion.

Changes of ground vegetation, soil chemical properties and microbiota following the surface fires in Scots pine forests

Abstract The aim of the study was to investigate the influence of low severity surface fires on the ground vegetation, soil chemical changes and soil microbiota in Scots pine stands on sandy soils (Arenosols). The study was conducted in the eastern part of Lithuania (55° 35′N, 26° 07′E). The annual investigations in 1–4-year-old burned sites showed that low severity surface fires mostly affected the above-ground part of the ground vegetation. The influence of surface fire on soil chemical properties and soil microbiota was minor. Only slight increases in pH and in the content of total N in soil organic layer were detected. Concentrations of mobile K2O and heavy metals (Cd, Cr, Cu, Mn, Zn and Fe) slightly increased in the mineral topsoil. The actinobacteria abundance increased in the soil organic layer and the mineral topsoil of the burned sites. The abundance of micromycetes decreased in the mineral topsoil after the surface fires.

Spontaneous Hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian Seaside: A Morphological Survey

We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija.

Tree-ring formation as an indicator of forest capacity to adapt to the main threats of environmental changes in Lithuania

Global changes occurring under different environmental conditions have changed stand competition, as well as nutrient and light availability, which has resulted in changes in productivity. Therefore, in the present study, the characteristics of tree-ring width formation of the prevailing Lithuanian tree species, Norway spruce, Scots pine and silver and downy birch, and key factors resulting in their differences during the last 36-year period were investigated at forest sites located on poor mineral oligotrophic and on nutrient-rich organic mesoeutrophic soils. The aim of the study was as follows: first, to separately detect the maximum possible seasonal effect of three groups of variables - meteorology, acidifying pollutants and surface ozone on the stem basal area increment (BAI) of the evaluated tree species; second, to assess the significance of each group of variables affecting the BAI of these tree species integrally with the remaining groups of variables. Norway spruce was found to be well adapted to recent environmental changes, which makes it one of the most favourable tree species for silviculture in the northeastern part of Europe. The rapid increases recorded in growth intensity since 1980 were attributed to the increase in air temperature, precipitation amount, nitrogen deposition during the vegetative stage and reductions in SO2 concentrations and S deposition. Scots pine demonstrated the highest level of resilience and capacity to adapt to recent global changes because its reaction to both negative and favourable environmental factors was best expressed. Silver and downy birch tree reactions to the effects of air concentrations of acidifying compounds, their deposition and surface ozone concentrations were the least expressed; however, a significant decline in growth intensity indicated that these tree species experienced a reduced resistance to recent changes in environmental conditions in the mature and over-mature age groups.

Erratum to: “Release and retention patterns of organic compounds and nutrients after the cold period in foliar litterfall of pure European larch, common beech and red oak plantations in Lithuania”

This study was carried out in alien warmth-tolerant forest plantations of red oak (Quercus rubra), common beech (Fagus sylvatica) and European larch (Larix decidua). We compared the changes in foliar litterfall mass and biochemical composition after five months of cold period. The mean mass of fresh foliar litterfall collected in late autumn was 30% higher in red oak compared to the larch and beech plantations. After the cold period, the reduction of foliar litterfall mass did not exceed 10% in any of the studied plantations. The fresh foliar litterfall of red oak was the richest in cellular fibre and easily decomposable glucose and nutrients such as P and Mg, larch was distinguished by the highest lignin, N, K and Ca concentrations, while beech fresh foliar litterfall was the poorest in the aforementioned nutrients. After the cold period, the changes in the biochemical composition of foliar litterfall revealed different patterns. In the spring, the beech and red oak foliar litterfall was the richest in N, P and Ca, meanwhile the larch foliar litterfall still had the highest concentration of lignin but, in contrast to the autumn, was the poorest in nutrients. After the cold period Lignin: N, C: N and C: P ratios reached critical values indicating that the foliar litterfall of beech and red oak had started to decompose. The highest lignin concentration and the highest and most stable Lignin: N, C: N, C: P and N: P ratios after the cold period indicated that the slowest foliar litterfall decomposition took place in the larch plantation.