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Ongoing climate change increasingly affects growth conditions of native conifers such as Picea abies (Norway spruce) and Pinus sylvestris (Scots pine) in Central Europe. These conifers are primarily cultivated for wood production. To obtain ecologically and economically stable forests, forestry seeks alternative species that might be less prone to novel climatic conditions, such as Cedrus libani (Lebanon cedar). We aim at investigating growth responses to climatic factors of C. libani compared to native P. abies and P. sylvestris in Central Europe for 25 years (1994–2019). Growth responses were used as a proxy for tolerance towards climatic stress events, such as heat and drought. Height, diameter at breast height (DBH) and radial increment were measured for 40-year-old tree stands of C. libani and native conifers. Radial growth responses to selected climate parameters were analysed using bootstrapped correlations with detrended growth index chronologies and growth response indices for drought years (2003, 2012, 2015, 2018). For C. libani, radial growth was positively correlated with high water availability in late winter and spring, while for P. abies, February and summer and for P. sylvestris, July showed such a relationship. Cedrus libani exhibited the highest resistance, recovery, and resilience in response to climatic extremes. Against the background of climate change, C. libani could serve as an alternative conifer species to establish climate-resistant viable forests in Central Europe. [ABSTRACT FROM AUTHOR]

The dynamics of six different needle parameters of Pinus sylvestris L. and Pinus ponderosa Dougl. ex P. & C. Laws. were examined retrospectively for a 112-year-old mixed stand in Brandenburg, Germany, using the needle trace method. Similarities were found in needle production, needle loss and needle density. However, needle age, needle retention and total number of needles revealed significant differences between the tree species, with higher values for P. ponderosa. Pinus ponderosa yielded approximately twice as much mean whole-crown needle dry mass as P. sylvestris. Furthermore, different branching systems could be detected between the species, with both pines following "Corner's rule". The results suggest that under identical growing conditions, P. ponderosa exhibits more efficient water use and can therefore maintain a bigger crown (as the basis for increased growth) than P. sylvestris. [ABSTRACT FROM AUTHOR]

• Skid trails exhibit a more species rich, light and moisture demanding vegetation. • More compacted soils and higher cover of bare soil on skid trails increase species richness. • The effects are strongly spatially limited to the skid trail itself. • Depending on the site properties, the effects might last long after the management. While it is well-known that skid trails in forests locally increase soil compaction and illumination, the effect on vegetation and its spatial and temporal variation have hardly been studied in temperate forests. We surveyed Norway Spruce (Picea abies), Scots Pine (Pinus sylvestris) and European Beech (Fagus sylvatica) dominated forests to reflect the range of the prevalent forests types and ecological gradients of Northern Bavaria, Germany. In each forest type, we chose skid trails with different times since last use (0–2 years ago, 3–6 years ago, ≥7 years ago) to address the temporal aspect and sampled 4-m2 plots on the trail itself, adjacent to the trail and in the forest interior to address the spatial aspect. We analysed the response of soil compaction, canopy cover, vascular plant and bryophyte species richness, vegetation cover and height, both in total and differentiated by layer, and mean ecological indicator values to the use of skid trails. Skid trails exhibited significantly higher soil compaction together with a more diverse, more light and moisture demanding vegetation compared to the forest interior. On the trails, graminoids were favoured over woody perennials. Vegetation adjacent to the skid trail resembled the forest interior, yet soil compaction exceeded that of the forest interior. Irrespective of time since last use, the soils on skid trails remained more compacted and likewise ecological response of understory vegetation did not change with time. Canopy cover and species richness responded strongly site-specific, and effects lasted the longest in the surveyed Scots Pine dominated forests but were diminished in European Beech dominated forests. Our results indicate a shift to a more ruderal and wetland-like vegetation on skid trails, which, however, hardly extended into the adjacent forest stand. Overall, plot-scale richness was higher on skid trails than in adjacent the adjacent forest, suggesting that skid trails could contribute to greater habitat diversity in managed forests. Since soils remained compacted even for several decades without use, a designated skid trail system is essential. There is a lack of long-term studies on the understory response to the use of skid trails and further research focussed on the persistence in time is needed. [ABSTRACT FROM AUTHOR]