What prevails in climatic response of Pinus sylvestris in-between its range limits in mountains: slope aspect or elevation?

Abstract

The roles of slope orientation and elevational temperature gradient were investigated for Scots pine (Pinus sylvestris L.) growth in the middle of its growth range, where these factors can significantly modulate microclimate and thus plant growth. We assumed that slope orientation causes more complex and severe effects than elevation, because it influences all three main factors of plant growth: light, heat and moisture. In addition to the total ring width, the earlywood and latewood width and latewood ratio were considered as variables that contain information about tree ring growth during the season and wood structure over all tree lifespan on three sampling sites at different elevations and opposite slopes.Despite the observed dependence of pine growth rate on temperature and solar radiation, the mean latewood ratio is stable and similar between all sampling sites, being presumably defined by the genotype of individual trees. The seasonality of the climatic response of trees growth is bound to spatiotemporal variation of the vegetative season timing due to the elevational temperature lapse and local warming. However, its direction is primarily defined by slope orientation, where southern slope is moisture-limited, even at adjacent sites, and divergent climatic reactions of earlywood (weak moisture-limited in the last decades) and latewood growth (temperature-limited) was revealed on the northern slope.

Non-linear Response to Cell Number Revealed and Eliminated From Long-Term Tracheid Measurements of Scots Pine in Southern Siberia

“…This might be linked with the species-specific predisposition and with the climate type of the study area. In the continental climate, the cambial activity rate exhibits unimodal and asymmetrical kinetics with a maximum closer to the onset of the season coinciding with earlywood development (Popkova et al, 2018 ; Fonti et al, 2020 ), which lowers the latewood proportion for Scots pine to about one-third of the ring as observed in Scots pine trees growing in various natural zones of the region (Zhirnova et al, 2020 , 2021 ). Therefore, the TRW climatic response was more focused on earlywood than latewood, and seasonal interval of significant correlations (i.e., May to the first half of June) has been consistent with the production of earlywood tracheids.…”

Small fluctuations in cell wall thickness in pine and spruce xylem: Signal from cambium?

“…In previous studies we found significant climatic response in radial growth and wood anatomy of both species in the study area. Cell production and radial growth is limited mainly by soil water availability in May-June (positive correlations with precipitation and negative ones with temperature), latewood CWT has positive correlation with temperature in the end of summer [29,44,45].…”

Air temperature as a determinant of the forest line in the Tatras

“…The measuring points were located in places where the position of the upper forest line was not exposed to major and direct landform-related impacts, such snow avalanches, debris flows, landslides, etc. All measuring points had similar exposure to minimize the difference in solar radiaton (Buffo 1972;Zhimova et al 2019). In addition to the 8 measuring points mentioned above, air temperature measurements were carried out at the Hala Gąsienicowa research station, which is located at 1520 m a.s.l.…”

“…The forest line is not only of interest to foresters or, more generally, botanists, but also to researchers dealing with inanimate nature, for example geomorphologists and climatologists (Fabijanowski 1955;Myczkowski 1964;Pawłowski 1972;Balon 1991aBalon , 1991bBalon , 1995Barry 1992;Heikkinen et al 1995;Kotarba 1987;Krzemień et al 1995;Piękoś-Mirkowa and Mirek 1996;Barber et al 2000;Kirchhefer 2000;Becker and Bugmann 2001;Jodłowski 2007;Körner 2009;Lebourgeois et al 2010;Jochner et al 2018;Kelsey et al 2018;Zhimova et al 2019). The latter group of researchers, in particular, have closely fol-lowed changes in the position of the individual vegetation zones, including the forest line, as indicators of climate change.…”