Effect of species proportion definition on the evaluation of growth in pure vs. mixed stands

Hubert Sterba, Miren del Rio, Andreas Brunner, Sonia Condes

Abstract


Aim of study: The aim of this paper is to compare differences in growth per hectare of species in pure and mixed stands as they result from different definitions of species proportions.

Area of Study: We used the data of the Spanish National Forest Inventory for Scots pine and beech mixtures in the province of Navarra and for Scots pine and Pyrenean oak mixtures in the Central mountain range and the North Iberic mountain range.

Material and Methods: Growth models were parameterized with the species growth related to its proportion as dependent variable, and dominant height, quadratic mean diameter density, and species proportion as independent variables. As proportions we use once proportions by basal area or by stand density index and once these proportions considering the species specific maximum densities.

Main Results: In the pine – beech mixtures, where the maximum densities do not differ very much between species, the mixing effects are very similar, independent of species proportion definitions. In the pine – oak mixture, where the maximum densities in terms of basal area are very different, the equations using the proportions calculated without reference to the maximum densities, result in a distinct overestimation of the mixing effects on growth.

Research highlights: When comparing growth per hectare of a species in a mixed stand with that of a pure stand, the species proportion must be described as a proportion by area considering the maximum density for the given species, wrong mixing effects could be introduced by inappropriate species proportion definitions.

Keywords: Mixing effects; proportion by area; Stand Density Index; overyielding; Pinus sylvestris L.; Fagus sylvatica L.; Quercus pyrenaica Willd.

 


Full Text:

PDF

References


Bravo-Oviedo A, Pretzsch H, Ammer C, Andenmatten E, Antón C, Barbati A, Barreiro S, Brang P, Bravo F, Brunner A, Coll L, Corona M, den Ouden J, Drössler L, Ducey MJ, Kaynas BY, Legay M, Löf M, Lesinski J, Mason B, Meliadis M, Manetti MC, Morneau F, Motiejunaite J, O'Reilly C, Pach M, Ponette Q, Del Río M, Short I, Skovsgaard JP, Souidi Z, Spathelf P, Sterba H, Stojanovic D, Strelcova K, Svoboda M, Valsta L, Verheyen K, Zlatanov T, 2014. European Mixed Forests: Definition and perspectives. Forest systems 23(3): 518-533.

Condés S, Del Rio M, Sterba H, 2013. Mixing effect on volume growth of Fagus sylvatica and Pinus sylvestris is modulated by stand density. Forest Ecology and Management 292: 86-95. http://dx.doi.org/10.1016/j.foreco.2012.12.013

Forrester DI, 2014. The spatial and temporal dynamics of species interactions in mixed-species forests: From pattern to process. Forest Ecology and Management 312: 282-292. http://dx.doi.org/10.1016/j.foreco.2013.10.003

Gamfeldt L, Snäll T, Bagchi R, Jonsson M, Gustafsson L, Kjellander P, Ruiz-Jaen MC, Fröberg M, Stendahl J, Philipson CD, 2013. Higher levels of multiple ecomixture services are found in forests with more tree species. Nature communications 4: 1340.

Griess VC, Knoke T, 2011. Growth performance, windthrow, and insects: meta-analyses of parameters influencing performance of mixed-species stands in boreal and northern temperate biomes. Canadian Journal of Forest Research 41: 1141-1159. http://dx.doi.org/10.1139/x11-042

Groot A, Adhikary S, Sharma M, Luckai N, Bell FW, Larocque GR, 2014. Effect of species composition on the production rate and efficiency of young Picea glauca-Populus tremuloides forests. Forest Ecology and Management 315: 1-11. http://dx.doi.org/10.1016/j.foreco.2013.12.017

Kelty MJ, 1992. Comparative productivity of monocultures and mixed-species stands. In: Kelty M.J. L.B.C., and Oliver C.D. (Ed.), The Ecology and silviculture of mixed-species forests. Kluwer Academic Publishers, Dordrecht (The Netherlands), pp. 125-141. http://dx.doi.org/10.1007/978-94-015-8052-6_8

Kennel R, 1965. Untersuchungen über die Leistung von Fichte und Buche im Rein-und Mischbestand. Sauerländer.

Légaré S, Paré D, Bergeron Y, 2004. The responses of black spruce growth to an increased proportion of aspen in mixed stands. Canadian Journal of Forest Research 34: 405-416. http://dx.doi.org/10.1139/x03-251

Perot T, Picard N, 2012. Mixture enhances productivity in a two-species forest: evidence from a modeling approach. Ecological Research 27: 83-94. http://dx.doi.org/10.1007/s11284-011-0873-9

Pretzsch H, 2005. Stand density and growth of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.): evidence from long-term experimental plots. European Journal of Forest Research 124: 193-205. http://dx.doi.org/10.1007/s10342-005-0068-4

Pretzsch H, 2009. Forest dynamics, growth and yield. A review, analysis of the present state, and Perspective. Springer.

Pretzsch H, Block J, Dieler J, Dong PH, Kohnle U, Nagel J, Spellmann H, Zingg A, 2010. Comparison between the productivity of pure and mixed stands of Norway spruce and European beech along an ecological gradient. Annals of Forest Science 67: 1-12. http://dx.doi.org/10.1051/forest/2010037

Pretzsch H, Schütze G, 2009. 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. European Journal of Forest Research 128: 183-204. http://dx.doi.org/10.1007/s10342-008-0215-9

Pretzsch H, Schütze G, Uhl E, 2013. Resistance of European tree species to drought stress in mixed versus pure forests: evidence of stress release by inter‐specific facilitation. Plant Biology 15: 483-495. http://dx.doi.org/10.1111/j.1438-8677.2012.00670.x

Prodan M, 1959. Umrechnung von Massen in Flächenanteile. Forstarchiv 30: 110-113.

Reineke L.H., 1933. Perfecting a stand-density index for even-aged forests. Journal of Agricultural Research 46: 627-638.

Río M, Sterba H, 2009. Comparing volume growth in pure and mixed stands of Pinus sylvestris and Quercus pyrenaica. Annals of Forest Science 66: 502-502. http://dx.doi.org/10.1051/forest/2009035

Sterba H, 1987. Estimating potential density from thinning experiments and inventory data. Forest Science 33: 1022-1034.




DOI: 10.5424/fs/2014233-06051

Webpage: www.inia.es/Forestsystems