title: 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 CO2. 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/m2. Although new species emerged, this new growth and small increases in oak biomass resulted in only 1.9 kg C/m2increase 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/m2, 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.
authors.affiliation: Institute of Environmental Sciences, University of Nyíregyháza, Nyíregyháza, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Fekete
authors.affiliation: Department of Crop and Soil Science, Oregon State University, Corvallis, OR, USA.
authors.forename: Kate
authors.initials: K
authors.lastname: Lajtha
authors.affiliation: Department of Soil Science and Water Management, Szent István University, Budapest, Hungary.
authors.forename: Zsolt
authors.identifier: 0000-0002-5637-2802
authors.initials: Z
authors.lastname: Kotroczó
authors.affiliation: Department of Tisza River Research, Danube Research Institute, Centre for Ecology of HAS, Debrecen, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Várbíró
authors.affiliation: Department of Land Management and Rural Development, University of Nyíregyháza, Nyíregyháza, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Varga
authors.affiliation: Department of Ecology, University of Debrecen, Debrecen, Hungary.
authors.forename: János Attila
authors.initials: JA
authors.lastname: Tóth
authors.affiliation: Centre for Agricultural Sciences, Research Institute of Nyíregyháza, University of Debrecen, Nyíregyháza, Hungary.
authors.forename: Ibolya
authors.initials: I
authors.lastname: Demeter
authors.affiliation: Institute of Forest Assets Management, University of West Hungary, Sopron, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Veperdi
authors.affiliation: Institute of Environmental and Earth Sciences, University of West Hungary, Sopron, Hungary.
authors.forename: Imre
authors.initials: I
authors.lastname: Berki
mesh_terms: D018533:Biomass; D002244:Carbon; D057486:Carbon Cycle; D057231:Climate Change; D065928:Forests; D012987:Soil; D013997:Time Factors; D014197:Trees
chemical_list: D012987:Soil; D002244:Carbon
keywords: Síkfőkút Forest; coarse woody debris; dry conditions in forest; forest stand composition and diversity change; net primary production; oak decline; soil carbon storage