Effect of Climate Change on the Growth of Endangered Scree Forests in Krkonoše National Park (Czech Republic)

Abstract

Scree forests with large numbers of protected plants and wildlife are seriously threatened by climate change due to more frequent drought episodes, which cause challenges for very stony, shallow soils. The effect of environmental factors on the radial growth of five tree species—European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst.), sycamore maple (Acer pseudoplatanus L.), European ash (Fraxinus excelsior L.), and mountain elm (Ulmus glabra Huds.)—was studied in the mixed stands (105–157 years) in the western Krkonoše Mountains (Czech Republic) concerning climate change. These are communities of maple to fir beechwoods (association Aceri-Fagetum sylvaticae and Luzulo-Abietetum albae) on ranker soils at the altitude 590–700 m a.s.l. Production, structure, and biodiversity were evaluated in seven permanent research plots and the relationships of the radial growth (150 cores) to climatic parameters (precipitation, temperature, and extreme conditions) and air pollution (SO2, NOX, ozone exposure). The stand volume reached 557–814 m3 ha–1 with high production potential of spruce and ash. The radial growth of beech and spruce growing in relatively favorable habitat conditions (deeper soil profile and less skeletal soils) has increased by 16.6%–46.1% in the last 20 years. By contrast, for sycamore and ash growing in more extreme soil conditions, the radial growth decreased by 12.5%–14.6%. However, growth variability increased (12.7%–29.5%) for all tree species, as did the occurrence of negative pointer years (extremely low radial growth) in the last two decades. The most sensitive tree species to climate and air pollution were spruce and beech compared to the resilience of sycamore and ash. Spectral analysis recorded the largest cyclical fluctuations (especially the 12-year solar cycle) in spruce, while ash did not show any significant cycle processes. The limiting factors of growth were droughts with high temperatures in the vegetation period for spruce and late frosts for beech. According to the degree of extreme habitat conditions, individual tree species thus respond appropriately to advancing climate change, especially to an increase in the mean temperature (by 2.1 °C), unevenness in precipitation, and occurrence of extreme climate events in the last 60 years.

Pinus contorta Douglas ex Loudon and climate change: A literature review of opportunities, challenges, and risks in European forests

“…Finally, climate change -in particular heatwaves, long-term droughts, extreme events, secondary pests -are significant threats to forest production and stability (Rößiger et al 2019;Vacek et al 2019Vacek et al , 2020Šimůnek et al 2020;Hájek et al 2021;D'Andrea et al 2022). Pinus contorta is susceptible to the synergism of extreme temperatures combined with high precipitation variability or low precipitation during the vegetation season, primarily during May-July (Lo et al 2010;Vacek et al 2021).…”

Growth response of seven multipurpose tree species to climatic factors: A case study from northwestern Himalayas, India

“…tree ring data (Bauwe et al 2015), since annual tree ring data serve as a valuable and indirect source of information about climate change and response (Fritts 1976). Moreover, knowing how trees develop in response to climatic variability is crucial for forecasting how various species will respond to climate change (Grogan, Schulze 2012;Jiao et al 2019;Hájek et al 2021). As stated in 2019 Special Report on climate change and land of the Intergovernmental Panel on Climate Change (IPCC), the mean air temperature already increased by 1.53 °C, and there was an increase in rainfall intensity, flooding and drought frequency, wildfire incidence and pest outbreaks compared to the pre-industrial period (before 1850).…”