Soil moisture dynamics in forest monocultures of beech, larch and spruce in a drought-prone region of Central Bohemia

Ing. Marta Kuželková

Disertační práce

Abstract:

Forests provide wide range of ecosystem services, including water retention, erosion control and microclimate regulation. Tree species differ in functional traits that may influence forest hydrology. Under ongoing climate change, increasing evapotranspiration demand and more frequent weather extremes may alter the balance between soil water recharge and depletion, putting the forest vitality at risk. Robust field data are therefore needed to better understand how contrasting tree species affect soil water dynamics under drought-prone conditions. This dissertation compares soil moisture dynamics under three ecologically contrasting and regionally important tree species: Norway spruce, European beech, and European larch. A long-term soil moisture monitoring network was established and evaluated over the 2021–2026 monitoring period and complemented by soil water potential measurements. The results showed pronounced and statistically significant differences in surface soil moisture among studied tree species. In surface soil layers, spruce repeatedly showed an early water depletion already in February. In contrast, beech and larch stands generally remained in a recharge phase until rapid depletion starting in mid April to early May, reaching even to deeper soil layers. Consequently, during peak summer, soil water storage in beech and larch stands dropped under spruce levels. However, during the winter recharge period, soil water storage under beech and larch was restored to saturation, whereas spruce often entered the following growing season with a water deficit (-10 kPa). However, the exceptionally warm year 2024 disrupted typical spring pattern. Under larch, soil moisture depletion occurred shortly after spruce, suggesting that warming may modify the usual species-specific differences in soil water dynamics. At the end of 2024 the soil water deficit approximated by soil potential decreased to-100 kPa in spruce even though a extreme precipitation occurred in September, recharging the beech and larch soil. The observed differences are likely associated with species-specific functional traits. Evergreen spruce appears to be disadvantaged by year-round interception, prolonged transpiration demand, and reduced recharge ability related to the character of its organic soil layer and lateral root system. In contrast, the seasonal loss of foliage and deeper rooting system of beech and larch trees allow more effective soil water recharge. These findings demonstrate that tree species composition can substantially affect soil water regimes under drought-prone conditions and may support forest adaptation strategies in Central European forests.

Keywords

tree species differences, TMS, climate change, tree traits, monitoring network, soil moisture, forest

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 2. 8. 2026

Obhajoba závěrečné práce

• Vedoucí: Ing. Lukáš Jačka, Ph.D.
• Oponent: Martin Šanda, externi, Václav Šípek, externi

Česká zemědělská univerzita v Praze

Fakulta životního prostředí

Doktorský studijní program / specializace:
Environmentální vědy o Zemi / Environmentální modelování