The Potential of Liming to Improve Drought Tolerance of Norway Spruce [Picea abies (L.) Karst.]

Wet events increase tree growth recovery after different drought intensities

Understanding the dynamics of tree recovery after drought is critical for predicting the state of tree growth in the context of future climate change. While there has been a great deal of researches showing that drought events can cause numerous significant negative effects on tree growth, the positive effects of post-drought wetting events on tree growth remain unclear. Therefore, we analyzed the effect of wet and dry events on the radial growth of trees in Central Asia using data on the width of tree rings. The results showed that 1) Drought is the main limiting factor for radial growth of trees in Central Asia, and that as the intensity and sensitivity of drought increases, tree resistance decreases and recovery rises, and more frequent droughts reduce tree resistance. 2) Tree radial growth varied significantly with wet and dry conditions, with wet events before and after drought events significantly enhancing tree radial growth. 3) When drought is followed by a wetting event, the relationship between tree resistance and recovery is closer to the "line of full resilience", with a significant increase in recovery, and compensatory growth is more likely to occur. Thus, wetting events have a significant positive effect on tree radial growth and are a key factor in rapid tree growth recovery after drought.

The key role of ecological resilience in radial growth processes of conifers under drought stress in the subalpine zone of marginal deserts

Global climate change is exacerbating drought pressure on forests. However, the response patterns and physiological mechanisms of conifer species to drought, specifically in terms of radial growth, ecological resilience and soil water utilization, are not clearly understood. This study aims to quantify the effects of resilience on radial growth and identify the role of soil moisture utilization strategies in the resilience of species under drought intensities. We focus on two conifer species, Picea crassifolia (spruce) and Pinus tabuliformis (pine), located on the southern edge of the Tengger Desert in northwestern China. The dynamics of radial growth and ecological resilience were identified, and the seasonal growth rates of species based on soil water were simulated using the VS-oscilloscope model under varying drought stress. The results showed that spruce growth and recovery contributed by soil water were suppressed with frequent severe droughts, leading to a decline in growth (-0.5 cm2 year-1/10a, p < 0.05), despite its greater resistance to mild and moderate drought (-4.63 %). However, pine exhibited a stronger recovery (+40.25 %, p < 0.05) and higher variation in growth (-0.3 cm2 year-1/10a, p < 0.05) under soil moisture stress, despite its weaker resistance to drought (-23.53 %, p < 0.05). These findings provide insights into the growth, resilience, and water adaptation mechanisms of species under drought events, and theoretical support for the conservation and management of conifer diversity and forest ecosystem stability in climate-sensitive regions.

Forest Soils—What’s Their Peculiarity?

Mankind expects from forests and forest soils benefits like pure drinking water, space for recreation, habitats for nature-near biocenoses and the production of timber as unrivaled climate-friendly raw material. An overview over 208 recent articles revealed that ecosystem services are actually the main focus in the perception of forest soil functions. Studies on structures and processes that are the basis of forest soil functions and ecosystem services are widely lacking. Therefore, additional literature was included dealing with the distinct soil structure and high porosity and pore continuity of forest soils, as well as with their high biological activity and chemical soil reaction. Thus, the highly differentiated, hierarchical soil structure in combination with the ion exchange capacity and the acid buffering capacity could be described as the main characteristics of forest soils confounding the desired ecosystem services. However, some of these functions of forest soils are endangered under the influence of environmental change or even because of forest management, like mono-cultures or soil compaction through forest machines. In the face of the high vulnerability of forest soils and increased threads, e.g., through soil acidification, it is evident that active soil management strategies must be implemented with the aim to counteract the loss of soil functions or to recover them.

The EpiDiverse Plant Epigenome-Wide Association Studies (EWAS) Pipeline

Bisulfite sequencing is a widely used technique for determining DNA methylation and its relationship with epigenetics, genetics, and environmental parameters. Various techniques were implemented for epigenome-wide association studies (EWAS) to reveal meaningful associations; however, there are only very few plant studies available to date. Here, we developed the EpiDiverse EWAS pipeline and tested it using two plant datasets, from P. abies (Norway spruce) and Q. lobata (valley oak). Hence, we present an EWAS implementation tested for non-model plant species and describe its use.