Drought Effects on Early Growth and Mortality of Three Oak Species in the Upper Rhine Valley

Abstract

Pedunculate oak and sessile oak are important natural species in the Upper Rhine Valley. The increasing mortality of these oak species has been observed since the 1980s in this region, mainly due to severe droughts. Turkey oak is known to be highly productive and drought-resistant. The goal of this article is therefore to investigate the adaptability to drought of these three young oak species growing at the same site, and to show to what extent Turkey oak can be substituted for these native oak species. Stand measurements and retrospective analyses of radial growth were performed within the framework of the eight-year-old "Mooswald" afforestation experiment in order to determine stand volume, mortality and resistance/resilience to drought for each species. Turkey oak shows significantly higher stand volume and significantly lower mortality than sessile oak. Values of these two parameters for Turkey oak and sessile oak are not significantly different from those of pedunculate oak. However, Turkey oak is not more resistant to drought than the other oak species. Sessile oak has the highest mortality and the smallest stand volume, while pedunculate oak is the least resilient to drought. These results are only a trend that must be confirmed in older stand stages and investigation in young stands must continue, supported by better monitoring and improved tools.

Tracing Real-Time Transnational Hydrologic Sensitivity and Crop Irrigation in the Upper Rhine Area over the Exceptional Drought Episode 2018–2020 Using Open Source Sentinel-2 Data

“…Environmental analyses and diachronic system models in the Upper Rhine Area (URA) have experienced increased scientific attention within the past years, mostly because of the high climate and surface change vulnerability of the region [34][35][36][37][38][39][40][41][42][43][44] . Manifold research has been carried out, which focuses on hydrologic or groundwater discharge and flow connectivity [45] , plant species vulnerability [10], landcover change and land-use development [34,39,40,46,47], soil erosion [48], climate variability [33,49,50], and chain effects of different climatic stressors [8,[51][52][53]. In a coupled ecological system, however, a broad variety of spatio-temporal components form the functional ecosystem connectivity, which includes not only historical and current landscape development but also different environmental and human response cycles, decision-making, perception, and affordances [13,14,[54][55][56][57].…”

“…The fine-grained silty and clayey deposition along the river L'Ill and the several tributaries of the river Rhine floodplain are prone to waterlogged conditions in locales with high groundwater levels. In Addition, in the 19th century, the floodplain forests almost completely disappeared during the canalization of the river Rhine, which caused considerable groundwater lowering and increased erosion downstream of Basel [10,85]. Since the end of the 18th century, however, there has been a trend towards strong local reforestation processes as an expression of socio-ecological transformation.…”