title: Discerning environmental factors affecting current tree growth in Central Europe.
abstract: We examined the effect of individual environmental factors on the current spruce tree growth assessed from a repeated country-level statistical landscape (incl. forest) survey in the Czech Republic. An extensive set of variables related to tree size, competition, site characteristics including soil texture, chemistry, N deposition and climate was tested within a random-effect model to explain growth in the conditions of dominantly managed forest ecosystems. The current spruce basal area increment was assessed from two consecutive landscape surveys conducted in 2008/2009 and six years later in 2014/2015. Tree size, age and competition within forest stands were found to be the dominant explanatory variables, whereas the expression of site characteristics, environmental and climatic drives was weaker. The significant site variables affecting growth included soil C/N ratio and soil exchangeable acidity (pH KCl; positive response) reflecting soil chemistry, long-term N-deposition (averaged since 1975) in combination with soil texture (clay content) and Standardized Precipitation Index (SPI), a drought index expressing moisture conditions. Sensitivity of growth to N-deposition was positive, although weak. SPI was positively related to and significant in explaining tree growth when expressed for the growth season. Except SPI, no significant relation of growth was determined to altitude-related variables (temperature, growth season length). We identified the current spruce growth optimum at elevations about 800ma.s.l. or higher in the conditions of the country. This suggests that at lower elevations, limitation by a more pronounced water deficit dominates, whereas direct temperature limitation may concern the less frequent higher elevations. The mixed linear model of spruce tree growth explained 55 and 65% of the variability with fixed and random effects included, respectively, and provided new insights on the current spruce tree growth and factors affecting it within the environmental gradients of the country.
authors: IFER - Institute of Forest Ecosystem Research, Cs. armády 655, 254 01 Jílové u Prahy, Czech Republic. Electronic address: Emil.Cienciala@ifer.cz.
authors: Emil
authors: E
authors: Cienciala
authors: IFER - Institute of Forest Ecosystem Research, Cs. armády 655, 254 01 Jílové u Prahy, Czech Republic.
authors: Radek
authors: R
authors: Russ
authors: Faculty of Science, Department of Ecosystem Biology, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic.
authors: Hana
authors: H
authors: Šantrůčková
authors: Institute of Botany, The Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic.
authors: Jan
authors: J
authors: Altman
authors: Faculty of Science, Department of Ecosystem Biology, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic; Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic.
authors: Jiří
authors: J
authors: Kopáček
authors: Czech Hydrometeorological Institute, Na Šabatce 2050/17, Komořany, 143 06 Prague, Czech Republic.
authors: Iva
authors: I
authors: Hůnová
authors: Global Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic.
authors: Petr
authors: P
authors: Štěpánek
authors: Czech Geological Survey, Klárov 3, 118 21 Prague, Czech Republic.
authors: Filip
authors: F
authors: Oulehle
authors: IFER - Institute of Forest Ecosystem Research, Cs. armády 655, 254 01 Jílové u Prahy, Czech Republic; Charles University in Prague, Faculty of Science, Department of Physical geography and Geoecology, Albertov 6, 12 843 Prague, Czech Republic.
authors: Jan
authors: J
authors: Tumajer
authors: Swedish University of Agricultural Sciences, Faculty of Forest Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden.
authors: Göran
authors: G
authors: Ståhl
mesh_terms: D000531:Altitude; D002980:Climate; D018153:Czech Republic; D055864:Droughts; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D008962:Models, Theoretical; D015999:Multivariate Analysis; D009584:Nitrogen / Q000032:analysis*; D028222:Picea / Q000254:growth & development*; D012044:Regression Analysis; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: Drought; Environmental change; Managed forest; N-deposition; Norway spruce; Tree increment