Long‐term effects of climate change on carbon storage and tree species composition in a dry deciduous forest

Abstract

Forest vegetation and soils have been suggested as potentially important sinks for carbon (C) with appropriate management and thus are implicated as effective tools in stabilizing climate even with increasing anthropogenic release of CO . Drought, however, which is often predicted to increase in models of future climate change, may limit net primary productio (NPP) of dry forest types, with unknown effects on soil C storage. We studied C dynamics of a deciduous temperate forest of Hungary that has been subject to significant decreases in precipitation and increases in temperature in recent decades. We resampled plots that were established in 1972 and repeated the full C inventory by analyzing more than 4 decades of data on the number of living trees, biomass of trees and shrubs, and soil C content. Our analyses show that the decline in number and biomass of oaks started around the end of the 1970s with a 71% reduction in the number of sessile oak stems by 2014. Projected growth in this forest, based on the yield table's data for Hungary, was 4.6 kg C/m . Although new species emerged, this new growth and small increases in oak biomass resulted in only 1.9 kg C/m increase over 41 years. The death of oaks increased inputs of coarse woody debris to the surface of the soil, much of which is still identifiable, and caused an increase of 15.5%, or 2.6 kg C/m , in the top 1 m of soil. Stability of this fresh organic matter input to surface soil is unknown, but is likely to be low based on the results of a colocated woody litter decomposition study. The effects of a warmer and drier climate on the C balance of forests in this region will be felt for decades to come as woody litter inputs decay, and forest growth remains impeded.

Drivers of above‐ground understorey biomass and nutrient stocks in temperate deciduous forests

“…The considered environmental gradients might have been too narrow to invoke changes in tree cover or tree litter quality. Current evidence on tree species responses to global change indeed suggests that compositional changes in the tree layer are expected under more extreme climatic conditions characterized by hotter drought periods (Allen et al, ; Buras & Menzel, ; Fekete et al, ). Hence, including more southern regions of Europe could have provided more insights on this.…”

Soil Organic Carbon Chemical Functional Groups under Different Revegetation Types Are Coupled with Changes in the Microbial Community Composition and the Functional Genes

“…While, the quality and function, and the stability of SOC largely depend on the chemical composition and molecular structure of SOC [9]. Previous studies have shown that different revegetation types have different influences on the distribution of soil C pools [10], especially between coniferous and broadleaf forests [11][12][13]. In previous decades several studies have focused on comparing SOC at different vegetation succession stages, while there are few reports concerning the SOC chemical composition under different revegetation types.…”

Understory Condition in an Oak Forest After 4 Decades for Oak Decline in Hungary

“…Descriptions of the geographic, climatic, and soil conditions, and vegetation of the forest were reported in detail by Jakucs (1985Jakucs ( , 1988, Tóth et al (2013) and Fekete et al (2014). The Quercetum petraeae-cerridis community with a dominant canopy of Q. petraea and Q. cerris deciduous tree species structure is presented in the works of Mázsa et al (2005), Kotroczó et al (2007) and Fekete et al (2017); the long-term dynamics of understory shrub layer and oak seedling dynamics are described among others in works of Misik and Kárász (2010) and Misik et al (2013Misik et al ( , 2017. The plots under study were made up of evenly aged temperate, mixed species deciduous forest that was at least 110 years old and had not been harvested for more than 55 years.…”