Growth and yield of mixed versus pure stands of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) analysed along a productivity gradient through Europe

Mixing of complementary tree species may increase stand productivity, mitigate the effects of drought and other risks, and pave the way to forest production systems which may be more resource-use efficient and stable in the face of climate change. However, systematic empirical studies on mixing effects are still missing for many commercially important and widespread species combinations. Here we studied the growth of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in mixed versus pure stands on 32 triplets located along a productivity gradient through Europe, reaching from Sweden to Bulgaria and from Spain to the Ukraine. Stand inventory and taking increment cores on the mainly 60–80 year-old trees and 0.02–1.55 ha sized, fully stocked plots provided insight how species mixing modifies the structure, dynamics and productivity compared with neighbouring pure stands. In mixture standing volume (+12 %), stand density (+20 %), basal area growth (+12 %), and stand volume growth (+8 %) were higher than the weighted mean of the neighbouring pure stands. Scots pine and European beech contributed rather equally to the overyielding and overdensity. In mixed stands mean diameter (+20 %) and height (+6 %) of Scots pine was ahead, while both diameter and height growth of European beech were behind (−8 %). The overyielding and overdensity were independent of the site index, the stand growth and yield, and climatic variables despite the wide variation in precipitation (520–1175 mm year−1), mean annual temperature (6–10.5 °C), and the drought index by de Martonne (28–61 mm °C−1) on the sites. Therefore, this species combination is potentially useful for increasing productivity across a wide range of site and climatic conditions. Given the significant overyielding of stand basal area growth but the absence of any relationship with site index and climatic variables, we hypothesize that the overyielding and overdensity results from several different types of interactions (light-, water-, and nutrient-related) that are all important in different circumstances. We discuss the relevance of the results for ecological theory and for the ongoing silvicultural transition from pure to mixed stands and their adaptation to climate change.

[1]  Christian Ammer,et al.  Admixing broadleaved to coniferous tree species: a review on yield, ecological stability and economics , 2008, European Journal of Forest Research.

[2]  Veronika Braunisch,et al.  Remotely sensed forest structural complexity predicts multi species occurrence at the landscape scale , 2013 .

[3]  A. Zingg,et al.  Comparison between the productivity of pure and mixed stands of Norway spruce and European beech along an ecological gradient , 2010, Annals of Forest Science.

[4]  H. Pretzsch,et al.  Analyzing size-symmetric vs. size-asymmetric and intra- vs. inter-specific competition in beech (Fagus sylvatica L.) mixed stands , 2014 .

[5]  A. Fischer,et al.  Restoration of Temperate Forests: An European Approach , 2012 .

[6]  Hans Pretzsch,et al.  Canopy space filling and tree crown morphology in mixed-species stands compared with monocultures , 2014 .

[7]  H. Pretzsch.  Species-specific allometric scaling under self-thinning: evidence from long-term plots in forest stands , 2005, Oecologia.

[8]  H. Pretzsch,et al.  Bodenzustand, Ernährungszustand und Wachstum von Fichten (Picea abies Karst.) auf Probeflächen des Friedenfelser Verfahrens in der Oberpfalz , 2003, Forstwissenschaftliches Centralblatt vereinigt mit Tharandter forstliches Jahrbuch.

[9]  M. Zasada,et al.  Productivity of mixed versus pure stands of oak (Quercus petraea (Matt.) Liebl. and Quercus robur L.) and European beech (Fagus sylvatica L.) along an ecological gradient , 2013, European Journal of Forest Research.

[10]  M. Loreau,et al.  Tropical tree diversity enhances light capture through crown plasticity and spatial and temporal niche differences , 2014 .

[11]  Mixed Norway spruce (Picea abies [L.] Karst) and European beech (Fagus sylvatica [L.]) stands under drought: from reaction pattern to mechanism , 2014, Trees.

[12]  Peter C. Jordan,et al.  Reviewing the Science and Implementation of Climate Change Adaptation Measures in European Forestry , 2011 .

[13]  R. Monserud,et al.  Modeling individual tree mortality for Austrian forest species , 1999 .

[14]  H. Hartmann.  Will a 385 million year‐struggle for light become a struggle for water and for carbon? – How trees may cope with more frequent climate change‐type drought events , 2011 .

[15]  Broadleaf seedling responses to warmer temperatures “chilled” by late frost that favors conifers , 2014, European Journal of Forest Research.

[16]  E. Assmann,et al.  The Principles of Forest Yield Study: Studies in the Organic Production, Structure, Increment and Yield of Forest Stands , 2013 .

[17]  T. Sariyildiz,et al.  Interactions between litter quality, decomposition and soil fertility: a laboratory study , 2003 .

[18]  Chunhua Zhang,et al.  Validation of temperature–precipitation based aridity index: Paleoclimatic implications , 2013 .

[19]  H. Rennenberg,et al.  Water shortage affects the water and nitrogen balance in Central European beech forests. , 2004, Plant biology.

[20]  G. Glatzel,et al.  The role of calcium uptake from deep soils for spruce (Picea abies) and beech (Fagus sylvatica) , 2006 .

[21]  H. Petterson.  Die Massenproduktion des Nadelwaldes , 1955 .

[22]  N. McDowell,et al.  Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought? , 2008, The New phytologist.

[23]  W. Fricke,et al.  Impact of late frost events on radial growth of common beech (Fagus sylvatica L.) in Southern Germany , 2006, European Journal of Forest Research.

[24]  H. Pretzsch,et al.  Mixed stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) can be more productive than monocultures. Evidence from over 100 years of observation of long-term experiments , 2014 .

[25]  David I Forrester,et al.  Transpiration and water-use efficiency in mixed-species forests versus monocultures: effects of tree size, stand density and season. , 2015, Tree physiology.

[26]  A. Cowie,et al.  Mixed-species plantations of Eucalyptus with nitrogen-fixing trees: A review , 2006 .

[27]  E. Schulze,et al.  Crown modeling by terrestrial laser scanning as an approach to assess the effect of aboveground intra- and interspecific competition on tree growth , 2013 .

[28]  J. Bauhus,et al.  The influence of mixed tree plantations on the nutrition of individual species: a review. , 2010, Tree physiology.

[29]  C. Ammer,et al.  Factors influencing the distribution and abundance of earthworm communities in pure and converted Scots pine stands , 2006 .

[30]  E. D. Martonne.  L'indice d'aridité , 1926 .

[31]  Rainer Matyssek,et al.  Growth and Defence in Plants , 2012, Ecological Studies.

[32]  Jerry F. Franklin,et al.  The Structure of Natural Young , Mature , and Old-Growth Douglas-Fir Forests in Oregon and Washington , 2010 .

[33]  Olivier Bouriaud,et al.  Crown plasticity enables trees to optimize canopy packing in mixed-species forests , 2015 .

[34]  Mathieu Jonard,et al.  Tree species mediated effects on leaf litter dynamics in pure and mixed stands of oak and beech , 2008 .

[35]  D. Forrester.  The spatial and temporal dynamics of species interactions in mixed-species forests: From pattern to process , 2014 .

[36]  A. Bolte,et al.  The north-eastern distribution range of European beech—a review , 2007 .

[37]  Dehai Zhao,et al.  Modeling neighborhood effects on the growth and survival of individual trees in a natural temperate species-rich forest , 2006 .

[38]  Hans Pretzsch,et al.  Representation of species mixing in forest growth models. A review and perspective , 2015 .

[39]  H. Pretzsch,et al.  Temporal variation of competition and facilitation in mixed species forests in Central Europe. , 2014, Plant biology.

[40]  H. Sterba,et al.  Comparing volume growth in pure and mixed stands of Pinus sylvestris and Quercus pyrenaica , 2009, Annals of Forest Science.

[41]  M. Caldwell,et al.  Hydraulic lift: consequences of water efflux from the roots of plants , 1998, Oecologia.

[42]  H. Pretzsch,et al.  Transgressive overyielding in mixed compared with pure stands of Norway spruce and European beech in Central Europe: evidence on stand level and explanation on individual tree level , 2009, European Journal of Forest Research.

[43]  L. Fehrmann,et al.  The relationship between tree species richness, canopy space exploration and productivity in a temperate broad-leaf mixed forest , 2013 .

[44]  M. G. Ryan,et al.  Thinking about efficiency of resource use in forests , 2004 .

[45]  G. Nabuurs,et al.  Statistical mapping of tree species over Europe , 2011, European Journal of Forest Research.

[46]  Aged Forests.  PERFECTING A STAND-DENSITY INDEX FOR EVEN- , 2010 .

[47]  Daniel Piotto,et al.  A meta-analysis comparing tree growth in monocultures and mixed plantations , 2008 .

[48]  Hans Pretzsch,et al.  Structural crown properties of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) in mixed versus pure stands revealed by terrestrial laser scanning , 2013, Trees.

[49]  M. Kelty.  Comparative productivity of monocultures and mixed-species stands , 1992 .

[50]  Harald Bugmann,et al.  Tree species richness promotes productivity in temperate forests through strong complementarity between species. , 2011, Ecology letters.

[51]  F. Kienast,et al.  Classifying the life-history strategies of trees on the basis of the Grimian model , 1994 .

[52]  H. Rennenberg,et al.  Stable isotope composition of organic compounds transported in the phloem of European beech--evaluation of different methods of phloem sap collection and assessment of gradients in carbon isotope composition during leaf-to-stem transport. , 2004, Plant biology.

[53]  M. Baumgarten,et al.  Nachhaltige Waldwirtschaft in Deutschland , 2005 .

[54]  H. W. Kassier.  Forest Dynamics, Growth and Yield: From Measurement to Model , 2011 .

[55]  H. Sterba,et al.  Mixing effect on volume growth of Fagus sylvatica and Pinus sylvestris is modulated by stand density , 2013 .

[56]  A. Jönsson.  Soil treatment effects on bark lesions and frost sensitivity of beech (Fagus sylvatica) in southern Sweden , 2000 .

[57]  P. Reich,et al.  Forest productivity increases with evenness, species richness and trait variation: a global meta‐analysis , 2012 .

[58]  W. Seiler,et al.  Potential risks for European beech (Fagus sylvatica L.) in a changing climate , 2006, Trees.

[59]  David A. Coomes,et al.  Patterns and Drivers of Tree Mortality in Iberian Forests: Climatic Effects Are Modified by Competition , 2013, PloS one.

[60]  H. Ellenberg.  Vegetation Mitteleuropas mit den Alpen : in ökologischer ,dynamischer und historischer Sicht , 2010 .

[61]  B. C. Larson,et al.  The Ecology and Silviculture of Mixed-Species Forests , 1992, Forestry Sciences.

[62]  Phillip B. Gibbons,et al.  Forest and woodland stand structural complexity: Its definition and measurement , 2005 .

[63]  P. Balandier,et al.  Influence of nurse birch and Scots pine seedlings on early aerial development of European beech seedlings in an open-field plantation of Central France , 2007 .

[64]  N. Picard,et al.  Mixture enhances productivity in a two-species forest: evidence from a modeling approach , 2011, Ecological Research.

[65]  D. Binkley,et al.  Nutritional interactions in mixed species forests: a synthesis , 2001 .

[66]  L. Walker,et al.  Competition and facilitation: a synthetic approach to interactions in plant communities , 1997 .

[67]  Thomas Knoke,et al.  Growth performance, windthrow, and insects: meta-analyses of parameters influencing performance of mixed-species stands in boreal and northern temperate biomes , 2011 .

[68]  Heinrich Spiecker,et al.  Silvicultural management in maintaining biodiversity and resistance of forests in Europe-temperate zone. , 2003, Journal of environmental management.

[69]  M. G. Ryan,et al.  Production and Nutrient Cycling in Mixed Plantations of Eucalyptus and Albizia in Hawaii , 1992, Forest Science.

[70]  H. Pretzsch,et al.  A Re-Evaluation of Reineke's Rule and Stand Density Index , 2005, Forest Science.

[71]  H. Ellenberg,et al.  Vegetation Mitteleuropas mit den Alpen , 1984 .

[72]  P. Vallet,et al.  Silver fir stand productivity is enhanced when mixed with Norway spruce: evidence based on large‐scale inventory data and a generic modelling approach , 2011 .

[73]  H. Pretzsch,et al.  Mischung und Produktivität von Waldbeständen. Ergebnisse langfristiger ertragskundlicher Versuche , 2013 .

[74]  Olivier Bouriaud,et al.  Competition for light and water play contrasting roles in driving diversity–productivity relationships in Iberian forests , 2014 .

[75]  N. Lust,et al.  Silvicultural interpretation of natural vegetation dynamics in ageing Scots pine stands for their conversion into mixed broadleaved stands , 2006 .

[76]  Assessing changes in species distribution from sequential large-scale forest inventories , 2014, Annals of Forest Science.

[77]  D. Binkley,et al.  Impact of several common tree species of European temperate forests on soil fertility , 2002 .

[78]  Photosynthetic capacity of Eucalyptus globulus is higher when grown in mixture with Acacia mearnsii , 2012, Trees.

[79]  Trevor H. Levere,et al.  Editor's Introduction to the Cumulative Index Volumes 44–64 , 2009 .

[80]  D. Benkert,et al.  Ellenberg, H., Vegetation Mitteleuropas mit den Alpen in ökologischer Sicht 3., verbesserte Aufl. 989 S., 499 Abb. und 130 Tab. Verlag Eugen Ulmer. Stuttgart, 1982. Preis: Ln. m. Schutzumschlag DM 120.— , 1984 .

[81]  C. Messier,et al.  The effect of biodiversity on tree productivity: from temperate to boreal forests , 2011 .

[82]  Marten Scheffer,et al.  The interplay of facilitation and competition in plant communities , 1997 .

[83]  G. Wieser,et al.  Case Study “Kranzberger Forst”: Growth and Defence in European Beech (Fagus sylvatica L.) and Norway Spruce (Picea abies (L.) Karst.) , 2012 .

[84]  Patrick Vallet,et al.  Effects of stand composition and tree size on resistance and resilience to drought in sessile oak and Scots pine , 2015 .

[85]  D. Hertel,et al.  On the niche breadth of Fagus sylvatica: soil nutrient status in 50 Central European beech stands on a broad range of bedrock types , 2006 .

[86]  David Cahan,et al.  Helmholtz in Gilded-Age America: The International Electrical Congress of 1893 and the Relations of Science and Technology , 2010 .

[87]  H. Pretzsch.  Forest Dynamics, Growth, and Yield , 2010 .

[88]  H. Sterba,et al.  Site conditions and definition of compositional proportion modify mixture effects in Picea abies - Abies alba stands , 2014 .

[89]  H. Sterba,et al.  A comparison of different methods to estimate species proportions by area in mixed stands , 2014 .

[90]  Thomas Seifert,et al.  Integrating selected ecological effects of mixed European beech-Norway spruce stands in bioeconomic modelling , 2008 .

[91]  H. Pretzsch,et al.  Resistance of European tree species to drought stress in mixed versus pure forests: evidence of stress release by inter-specific facilitation. , 2013, Plant biology.

[92]  F. Lebourgeois,et al.  Mixed stands reduce Abies alba tree-ring sensitivity to summer drought in the Vosges mountains, western Europe , 2013 .

[93]  H. Pretzsch,et al.  Morphological plasticity of European beech (Fagus sylvatica L.) in pure and mixed-species stands , 2013 .

[94]  D. Forrester,et al.  Light absorption and light-use efficiency in mixtures of Abies alba and Picea abies along a productivity gradient , 2014 .

[95]  Crown responses to neighbor density and species identity in a young mixed deciduous stand , 2014, Trees.

[96]  L. Vesterdal,et al.  Influences of evergreen gymnosperm and deciduous angiosperm tree species on the functioning of temperate and boreal forests , 2015, Biological reviews of the Cambridge Philosophical Society.

[97]  Olivier Bouriaud,et al.  Tree diversity does not always improve resistance of forest ecosystems to drought , 2014, Proceedings of the National Academy of Sciences.