Interception and soil water relation in Norway spruce stands of different age during the contrasting vegetation seasons of 2017 and 2018

Abstract

Interception, soil moisture and soil water potential were observed in four Norway spruce stands of different age in two subsequent vegetation seasons 2017 and 2018. Vegetation season 2018 can be characterized as being abnormally hot and dry with only 66% of precipitation in comparison with normal conditions. The interception of spruce increased with the stand age and its dimensions, ranging between 16 and 48% in 2017 and in the majority of stands even increasing in 2018. The soil moisture significantly decreased during the vegetation season 2018, with soil water potential close to the permanent wilting point (–1.5 MPa) for a substantial part of the monitored period. Differences between individual stands were observed in terms of the soil water potential (SWP) development which does not follow the interception patterns suggesting that the stand transpiration is a driving factor responsible for the soil water budget. In all stands, with the exception of the oldest one, the SWP of the upper soil horizon was less than 1.5 MPa for more than 80 days. In such extreme conditions the drought would negatively influence any Norway spruce stand regardless of its age or structure.

Sap flow and growth response of Norway spruce under long-term partial rainfall exclusion at low altitude

“…In 2016 soil water potential (SWP [bar]) was measured using gypsum blocks GB2 (EMS Brno, Czech Republic) once per hour at three different depths (10, 25 and 40 cm), on two sites per treatment. It is important to note that the measuring range of the gypsum blocks is 0 - -15 bar (SWP value generally referred as permanent wilting point ( Hsiao, 1973 ; Šrámek et al., 2019 ), so all SWP records below this value are marked as -15 bar. In 2015, we conducted the measurements of soil water content (SWC, [%]) within the first 15 cm using (TRIME-PICO 32 Probes, IMKO Micromodultechnik, Germany), weekly on 20 points in PE (including under foil cover and between trees in rows, without cover) and 20 points in PC.…”

Different Adaptive Potential of Norway Spruce Ecotypes in Response to Climate Change in Czech Long-Term Lowland Experiment

“…The poor condition of spruce stands resulting from drought is often compounded by bark beetle infestations, further exacerbating the decline in spruce stands [6,7]. Norway spruce has a limited capacity to adapt to summer droughts due to its shallow root system, making spruce stands highly susceptible to adverse climatic events, such as droughts and windstorms [8][9][10][11][12]. Additionally, damage caused by browsing or bark stripping by hoofed game animals weakens spruce stands, making them more vulnerable to climatic factors, and especially drought [13,14].…”