Effects of common oak (Quercus robur L.) defolition on the soil properties of an oak forest in Western Plain of Romania


  • Aurelia Oneț Faculty of Environmental Protection, University of Oradea, Romania
  • Alin Teușdea Faculty of Environmental Protection, University of Oradea, Romania
  • Nicușor Boja Faculty of Natural Sciences, Engineering and Informatics, “Vasile Goldiş” Western University of Arad
  • Cristian Domuța Faculty of Environmental Protection, University of Oradea, Romania
  • Cristian Oneț Faculty of Environmental Protection, University of Oradea, Romania




forest ecosystems, forest soils, defoliated oak forests, soil microorganisms


This study was conducted to evaluate the variability of the chemical properties of the soil of an oak forest affected by defoliation and the corresponding microbial abundance. Soil samples were collected from a control zone (zone 1) without outbreaks of defoliating insects and from a sample zone (zone 2) where the trees were affected by Lymantria dispar L. defoliation. The research was conducted to determine the changed conditions for soil microorganisms produced as a consequence of defoliation. The results indicated, by means of analysis of variance (two-way ANOVA, P = 0.05), statistically significant differences (P < 0.0001) with respect to soil hydrolytic acidity, pH, ammonium nitrogen, heterotrophic bacteria, nitrogen fixing bacteria from genus Azotobacter and fungi. The data revealed a low number of heterotrophic bacteria and low pH values in samples taken from the area affected by defoliation. Soils under stands of defoliated trees showed higher values with respect to soil acidity, ammonium nitrogen, fungi and nitrogen fixing bacteria Azotobacter. Moreover, the soil moisture, nitrate nitrogen, organic matter content, organic carbon, the number of heterotrophic bacteria and the number of bacteria from genus Azotobacter exhibited statistically significant seasonal differences between the two zones studied. The correlations between the tested parameters showed that soil parameters such as moisture content, soil acidity, pH, organic matter content, organic carbon, total nitrogen and nitrate nitrogen are important factors influencing the soil populations of aerobic mesophilic heterotrophic bacteria, fungi and nitrogen fixing bacteria in the studied forest ecosystem.


Abdi H., Lynne J. Williams, 2010. Principal Component Analysis. John Wiley & Sons, Inc. WIREs Comp Stat 2010 2: 433-459. Ahangar M.A., DarG.H.,Bhat Z.A., 2012. Growth response and nutrient uptake of blue pine (Pinus wallichiana) seedlings inoculated with rhizosphere microorganisms under temperate nursery conditions. Annals ofForestResearch 55(2):217-227. Aquilanti L., Favilli F., Clemeti F., 2004. Comparison of different strategies for isolation and preliminary identification of Azotobacter from soil samples. Soil. Biol. Biochem.36:1475–1483. DOI: 10.1016/j.soilbio. 2004.04.024 Atlas R.M., 2004. Handbook of Microbiological Media. 3rd edition. CRC Press, New York. DOI: 10.1201/ 9781420039726 Bölter M., Bloem J., Meiners K., Möller R., 2002. Enumeration and biovolume determination of microbial cells – a methodological review and recommendations for applications in ecological research. Biology and Fertility of Soils 36(4):249-259. DOI: 10.1007/s00374-002-0537-6 6.CampbellR.W., Sloan R.J., 1977.Foreststand responses to defoliation by the gypsy moth.ForestScience Monograph 19:1-32. Cardelli R., Marchini F., Saviozzi A., 2012. Soil organic matter characteristics, biochemical activity and antioxidant capacity in Mediterranean land use systems. Soil Tillage Research 120:8-14. DOI: 10.1016/ j.still.2012.01.005 Chen X.L., Wang D.W., Wang J., Diao J.J., Zhang J., Guan Q.W., 2015. Soil microbial functional diversity and biomass as affected by different thinning intensities in a Chinese fir plantation. Applied Soil Ecology 92:35-44. DOI: 10.1016/j.apsoil.2015.01.018 Deckers J.A., Nachtergaele F.O., Spaargaren O.C. (Eds), 1998. World Reference Base for Soil Resources. Introduction ISSS/ISRIC/FAO. Acco, Leuven/Amersfoort: 165 pp. Dequiedt S.,Thioulouse J., Jolivet C., Saby N., Lelievre M., Maron P.A., Martin M.P., Bouré N.C., Toutain B., Arrouays D., Lemanceau P., Ranjard L., 2009. Biogeographical patterns of soil bacterial communities. Environmental Microbiology Reports 1(4):251-255. DOI: 10.1111/j.1758-2229.2009.00040.x Drenovski E.R, Steenwerth K.L., Jackson L.E., Scow K.M., 2010. Land use and climatic factors structure regional patterns in soil microbial communities. Global Ecology and Biogeography19(1):27-39. DOI: 10.1111/j.1466-8238.2009.00486.x Frostegård Å., Bååth E., Tunlid A., 1993. Shifts in the structure of soil microbial communities in limed forests as revealed by phospholipid fatty acid analysis. Soil Biology and Biochemistry 25:723-730. DOI: 10.1016/0038-0717(93)90113-P Gakis S., Orfanoudakis M., Papaioannou A., Mantzanas K., Papanastasis V., Alifragis D., Seilopoulos D., Kostakis S., 2014. Long term evolution of tree growth, understorey vegetation and soil properties in a silvopastoral system of northernGreece. Annals ofForestResearch 57(2): 247-265. Gaublomme E., De Vos B., Cools N., 2006. An indicator for microbial biodiversity in forest soils. INBO. R.2006.40 InstituutvoorNatuur- en Bosonderzoek,Brussels:129. Hackl E., Zechmeister-Boltenstern S., Bodrossy L., Sessitsch A., 2004. Comparison of diversities and composition of bacterial populations inhabiting natural forest soils. Applied Environmental Microbiology. 70(9):5057-5065. DOI: 10.1128/AEM.70.9.5057-5065.2004 Hammer Ø., Harper D.A.T., Ryan P.D., 2001. PAST: Paleontological statistics software package for education and data analysis. Palaeontologia Electronica 4(1): 9pp. (http://palaeo-electronica.org/2001_1/past/issue1_01.htm). Johnson D., Curtis D., 2001. Effects of forest management on soil C and N storage:meta analysis. ForestEcology and Management 140:227-238. DOI: 10.1016/S0378-1127(00)00282-6 Lovett M.G., Christenson L.M., Groffman P.M., Jones C.G., Hart J.E., Mitchell M.J., 2002. Insect defoliation and nitrogen cycling in forests. Bioscience 54(4):335-341. DOI: 10.1641/0006-3568(2002)052[0335: IDANCI]2.0.CO;2 Mahara Gh., 2001. Meteorology.UniversityofOradeaPublishing House. Mahara Gh., 1977. Crisurilor Plain, in the vol. Crisurilor Plain, Fast Cris, Beius Country. Scientific and Encyclopaedic Publishing House. Mellec A., Michalzik B., 2008. Impact of a pine lappet (Dendrolimus pini) mass outbreak on C and N fluxes to the forest floor and soil microbial properties in a Scots pine forest in Germany. Canadian Journal of ForestResearch 38(7): 1829-1841. DOI: 10.1139/X08-045 Pal S., Panwar P., Bhardwaj D.R., 2012. Soil quality under forest compared to other land uses in acid soil of North Western Himalaya, India. Annals ofForestResearch 56(1):187-198. Preem J.,Truu J., Truu M., Mander U., Oopkaup K., Lohmus K.,2012. Bacterial community structure and its relationship to soil physico-chemical characteristics in alder stands with different management histories. Ecological Engineering 49:10-17. DOI: 10.1016/j.ecoleng.2012.08.034 Quinn G.P., Keough M.J., 2002. Experimental design and data analysis for biologists. CambridgeUniversityPress, The EdinburghBuilding, CambridgeCB2 2RU, UK, ISBN 0 521 811287 (hb), ISBN 978-0521009768(pb), p. 542. DOI: 10.1017/CBO9780511806384 Rasche, F., Knapp D., Kaiser C., Koronda M., Kitzler B., Boltenstern S., Richter A., Sessitsch A., 2010. Seasonality and resource availability control bacterial and archaeal communities in soils of a temperate beech forest. The ISME Jounal Mutidiciplinnary Journal of Microbial Ecology 5:389-402. Sri Lakshmi A., Narasimha G., 2012. Production of cellulases by fungal cultures isolated from forest litter soil. Annals ofForestResearch 55(1): 85-92. Stremi-ska M.A., Blaszczyk M., Kolk A., 2006. Microbial abundance and some of their physiological activities in soil organic horizon of pine forest affected by insect herbivory. Polish Journal of Environment Studies 15(6):905-914. Winn W., Allen S., Jande W., Koneman E., Procop G., Schreckenberger P., Woods G., 2006. Koneman̕s Color Atlas and Textbook of Diagnostic Microbiology, sixth edition. Lippincott Williams & Wilkins, Publisher.






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