Growth-climate responses of Picea sitchensis (Bong.) Carr. versus Picea abies (L.) Karst. in the British Isles and Central Europe

Introduced tree species have become increasingly important in the context of the ongoing climate change. This paper focuses on the dendrochronology of the most widespread introduced tree species in the British Isles – Sitka spruce (Picea sitchensis [Bong.] Carr.) – in comparable soil conditions in England, Czechia, and Slovakia. The research aims to evaluate the growth dynamics and the influence of climatic factors on this tree species while comparing it with economically main tree species in Europe – Norway spruce (Picea abies [L.] Karst.). Based on the analysis of 150 increment cores, the radial growth of Sitka spruce was on average 24.2% higher than that of Norway spruce. The highest increments in 52 to 62-year-old stands were achieved in England by both Sitka spruce (8.7mm) and Norway spruce (7.0 mm). In terms of negative pointer years (NPYs), there was no difference in the number of years with a significantly low increment between the two species at any site. The lowest effect of climatic factors on growth was found in Czechia, while the highest was in England. Higher resistance to climate was found for Sitka compared to Norway spruce. In general, the main limiting factor for the growth was the lack of precipitation in the previous year’s vegetation season, or heavy frost in England. In Central Europe, due to low precipitation, Sitka spruce will not be a substantial introduced tree species in the future, but on suitable sites, it can achieve high production potential and play a significant role for increasing stand diversity in the face of climate change

Dendrochronological data from twelve countries proved definite growth response of black alder (Alnus glutinosa [L.] Gaertn.) to climate courses across its distribution range

Black alder (Alnus glutinosa [L.] Gaertn.) is an important component of riparian and wetland ecosystems in Europe. However, data on the growth of this significant broadleaved tree species is very limited. Presently, black alder currently suffers from the pathogen Phytophthora and is particularly threatened by climate change. The objective of this study was to focus on the impact of climatic variables (precipitation, temperature, extreme climatic events) on the radial growth of alder across its geographic range during the period 1975–2015. The study of alder stands aged 46–108 years was conducted on 24 research plots in a wide altitude range (85–1015 m) in 12 countries of Europe and Asia. The most significant months affecting alder radial growth were February and March, where air temperatures are more significant than precipitation. Heavy frost and extreme weather fluctuations in the first quarter of the year were the main limiting factors for diameter increment. Within the geographical setting, latitude had a higher effect on radial growth compared to longitude. However, the most important variable concerning growth parameters was altitude. The temperature’s effect on the increment was negative in the lowlands and yet turned to positive with increasing altitude. Moreover, growth sensitivity to precipitation significantly decreased with the increasing age of alder stands. In conclusion, the growth variability of alder and the number of negative pointer years increased with time, which was caused by the ongoing climate change and also a possible drop in the groundwater level. Riparian alder stands well supplied with water are better adapted to climatic extremes compared to plateau and marshy sites

Comparison of growth of northern red oak (Quercus rubra L.) and durmast oak (Quercus petraea [Mattusch.] Liebl.) under similar growth conditions

The impacts of climate change on forest stands are manifested in different ways and intensity. Changes in the species composition of forest stands due to the different tolerance of forest species to the effects of climate change are one of the consequences too. In this context, introduced tree species are often mentioned as a possible replacement for dying autochthonous species. Of the deciduous species, it is mainly northern red oak. The aim of this paper is to compare selected quantitative (number of trees, basal area, merchantable volume, basal area increment and volume increment) and qualitative (crop trees) characteristics in one stand of the northern red oak at the age of 54 years and in two stands of durmast oak (age 57 and 58 years) in comparable site conditions. Achieved results showed higher values in all investigated quantitative parameters in the northern red oak stand compared to durmast oak stands. The merchantable volume in the northern red oak stand was 473 m3 per hectare in the tended subplots and 742 m3 ha–1 in the control ones. On the subplots with durmast oak, it was only from 228 to 289 m3 ha–1 in the subplots with thinning and 226 to 357 m3 ha–1 in the control areas. The same results were obtained for the category of crop trees. It means 230 m3 ha–1 for the northern red oak and 28 to 121 m3 ha–1 for durmast oak. The well-known fact about the higher quantitative production of the northern red oak compared to durmast oak was confirmed