Quantifying Competitiveness in Woody Plants

Abstract

A concept is presented for analysing and quantifying the competitiveness of woody plants. Efficiency ratios are defined that relate resource investments and gains to above- and belowground space sequestration. Such efficiencies are exemplified in comparisons between young and mature trees of European beech (Fagus sylvatica) and Norway spruce (Picea abies), resulting in remarkable consistencies across plant age and species. The demonstration extends to assessments of the inter- and intra-specific competition between young beech and spruce plants in a phytotron study, using CO₂/O₃ regimes as disturbants for examining the sensitivity of the efficiency ratios. In mixed plantations, the growth of spruce was enhanced and that of beech reduced as compared with the corresponding monocultures. This effect related to a high efficiency of spruce in aboveground space sequestration per resource investment, whereas the efficiency in carbon gain (return per unit of crown volume) was of minor importance. In contrast, beech displayed advantages in belowground space sequestration. However, competitiveness of young trees was hardly affected by the applied CO₂/O₃ treatments. The concept proves to be adequate for quantitatively comparing competitiveness across species, age and growth conditions. One further efficiency ratio, i.e., volume-related respiratory and transpiratory costs for sustaining functionality in resource sequestration, deserves attention in achieving a mechanistic understanding of competitive behaviour, in particular, in woody plants.

Abbreviations

DW: dry weight

J_max: maximum electron transport rate

SRL: specific fine root length

V_cmax: maximum carboxylation velocity of ribulose bisphosphate carboxylase

Φ_CO2 : quantum yield of CO₂ gas exchange

Key words

Competition - European beech (Fagus sylvatica) - maintenance costs - Norway spruce (Picea abies) - ontogenetic scaling - resource gain - space sequestration

References

• 01 Bazzaz,  F. A.. (1996) Plants in changing environments: linking physiological, population and community ecology. Cambridge; Cambridge University Press
• 02 Bentson,  G. M., and Wayne,  P. M.. (2000);  Characterizing the size-dependence of resource acquisition within crowded plant populations.  Ecology. 81 1072-1085
• 03 Bond,  B. J.. (2000);  Age-related changes in photosynthesis of woody plants.  Trends in Plant Science. 5 349-353
• 04 Conolly,  J.,, Wayne,  P.,, and Bazzaz,  F. A.. (2001);  Interspecific competition in plants: how well do current methods answer fundamental questions?.  American Naturalist. 157 107-125
• 05 Ellenberg,  H.. (1996) Vegetation Mitteleuropas mit den Alpen, 5. Auflage. Stuttgart; Ulmer Verlag
• 06 Falge,  E.,, Graber,  W.,, Siegwolf,  R.,, and Tenhunen,  J. D.. (1996);  A model of gas exchange response of Picea abies to habitat conditions.  Trees - Structure and Function. 10 227-287
• 07 Grace,  J. B., and Tilman,  D.. (1990) Perspectives on plant competition. San Diego; Academic Press
• 08 Grams,  T. E. E.,, Anegg,  S.,, Häberle,  K. H.,, Langebartels,  C.,, and Matyssek,  R.. (1999);  Interactions of chronic exposure to elevated CO₂ and O₃ levels in the photosynthetic light and dark reactions of European beech (Fagus sylvatica). .  New Phytologist. 144 95-107
• 09 Hubbard,  R. M.,, Ryan,  M. G.,, Stiller,  V.,, and Sperry,  J. S.. (2001);  Stomatal conductance and photosynthesis vary linearly with plant hydraulic conductance in ponderosa pine.  Plant, Cell and Environment. 24 113-121
• 10 Huber-Sannwald,  E.,, Pyke,  D. A.,, and Caldwell,  M. M.. (1996);  Morphological plasticity following species-species recognition and competition between two perennial grasses.  American Journal of Botany. 83 919-932
• 11 Huber-Sannwald,  E.,, Pyke,  D. A.,, and Caldwell,  M. M.. (1997);  Perception of neighbouring plants by rhizomes and roots: morphological manifestations of clonal plant.  Canadian Journal of Botany. 75 2146-2157
• 12 Keddy,  P. A.. (1989) Competition. London; Chapman & Hall
• 13 Kreutzer,  K.,, Göttlein,  A.,, Pröbstle,  P.,, and Zuleger,  M.. (1991) Höglwaldforschung 1982 - 1989. Zielsetzung, Versuchskonzept, Basisdaten. Forstwissenschaftliche Forschungen, Ökosystemforschung Höglwald: Auswirkungen von saurer Beregnung und Kalkung in einem Fichtenaltbestand. Kreutzer, K. and Göttlein, A., eds. Hamburg, Berlin; Paul Parey Verlag pp. 11-22
• 14 Küppers,  M.. (1984);  Carbon relations and competition between woody species in a Central European hedgerow. III. Carbon and water balance on the leaf level.  Oecologia. 65 94-100
• 15 Küppers,  M.. (1985);  Carbon relations and competition between woody species in a Central European hedgerow. IV. Growth form and partitioning.  Oecologia. 66 343-352
• 16 Küppers,  M.. (1989);  Ecological significance of above-ground architectural patterns in woody plants - a question of cost-benefit relationships.  Trends in Ecology and Evolution. 4 375-379
• 17 Küppers,  M.. (1994) Canopy gaps: competitive light interception and economic space filling - a matter of whole-plant allocation. Exploitation of environmental heterogeneity by plants - ecophysiological processes above and below-ground. Caldwell, M. M. and Pearcy, R. W., eds. San Diego; Academic Press pp. 111-144
• 18 Lippert,  M.,, Häberle,  K.-H.,, Steiner,  K.,, Payer,  H.-D.,, and Rehfuess,  K. E.. (1996);  Interactive effects of elevated CO₂ and O₃ on photosynthesis and biomass production of clonal 5-year-old Norway spruce [Picea abies (L) Karst] under different nitrogen nutrition and irrigation treatments:.  Trees - Structure and Function. 10 382-392
• 19 Matyssek,  R., and Schulze,  E.-D.. (1987);  Heterosis in hybrid larch (Larix decidua x leptolepis) II. Growth characteristics.  Trees - Structure and Function. 1 225-231
• 20 Matyssek,  R., and Schulze,  E.-D.. (1988);  Carbon uptake and respiration in above-ground parts of a Larix decidua × leptolepis tree.  Trees - Structure and Function. 2 233-241
• 21 Mooney,  H. A., and Winner,  W. E.. (1991) Partitioning response of plants to stress. Response of plants to multiple stresses. Mooney, H. A., Winner, W. E., and Pell, E. J., eds. San Diego; Academic Press pp. 129-141
• 22 Payer,  H.-D.,, Blodow,  P.,, Köfferlein,  M.,, Lippert,  M.,, Schmolke,  W.,, Seckmeyer,  G.,, Seidlitz,  H.,, Strube,  D.,, and Thiel,  S.. (1993) Controlled environment chambers for experimental studies on plant responses to CO₂ and interactions with pollutants. Design and execution of experiments on CO₂ enrichment. Schulze, E.-D. and Mooney, H. A., eds. Brussels; Commission European Communities pp. 127-145
• 23 Pretzsch,  H.,, Kahn,  M.,, and Grote,  R.. (1998);  Die Fichten-Buchen-Mischbestände des Sonderforschungsbereiches “Wachstum oder Parasitenabwehr?” im Kranzberger Forst.  Forstwissenschaftliches Centralblatt. 117 241-257
• 24 Reekie,  E. G., and Bazzaz,  F. A.. (1989);  Competition and patterns of resource use among seedlings of five tropical trees grown at ambient and elevated CO₂.  Oecologia. 79 212-222
• 25 Reitmayer,  H.. (2000) Quantifizierung des spektralen Angebotes photosynthetisch aktiver Strahlung (PAR) innerhalb eines Fichten/Buchen-Mischbestandes - Entwicklung und Aufbau eines Vielkanalmeßsystems zur Erfassung des Sonnenspektrums im Wellenlängenbereich von 400 bis 850 nm. Universität München; Doctoral Thesis
• 26 Reitmayer,  H.,, Werner,  H.,, and Fabian,  P.. (2002);  A novel system for spectral analysis of solar radiation within a mixed beech-spruce stand.  Plant Biology. 4 159-164
• 27 Roloff,  A.. (1988);  Morphologie der Kronenentwicklung von Fagus sylvatica L. (Rotbuche) unter besonderer Berücksichtigung neuartiger Veränderungen: II. Strategie der Luftraumeroberung und Veränderungen durch Umwelteinflüsse.  Flora. 180 297-338
• 28 Ryan,  M. G.,, Binkley,  D.,, and Fownes,  J. H.. (1997);  Age-related decline in forest productivity: pattern and process.  Advances in Ecological Research. 27 213-262
• 29 Schulze,  E. D.,, Küppers,  M.,, and Matyssek,  R.. (1986) The roles of carbon balance and branching pattern in the growth of woody species. On the economy of plant form and function. Givnish, T. J., ed. Cambridge; Cambridge University Press pp. 585-602
• 30 Schwinning,  S.. (1996);  Decomposition analysis of competitive symmetry and size structure dynamics.  Annals of Botany. 77 47-57
• 31 Schwinning,  S., and Weiner,  J.. (1998);  Mechanisms determining the degree of size asymmetry in competition among plants.  Oecologia. 113 447-455
• 32 Tilman,  D.. (1987);  The importance of the mechanisms of interspecific competition.  American Naturalist. 129 769-774
• 33 Thiel,  S.,, Döhring,  T.,, Köfferlein,  M.,, Kosak,  A.,, Martin,  P.,, and Seidlitz,  H. K.. (1996);  A phytotron for plant stress research: how far can artificial lighting compare to natural sunlight?.  Journal of Plant Physiology. 148 456-463
• 34 Tremmel,  D. C., and Bazzaz,  F. A.. (1995);  Plant architecture and allocation in different neighborhoods - implications for competitive success.  Ecology. 76 262-271
• 35 von Caemmerer,  S., and Farquhar,  G. H.. (1981);  Some relationships between the biochemistry of photosynthesis and the gas exchange of leaves.  Planta. 153 376-387
• 36 Waring,  R. H., and Schlesinger,  W. H.. (1985) Forest Ecosystems, Concepts and Management. San Diego; Academic Press pp. 340

Section Editor: H. Rennenberg