, Volume 25, Issue 4, pp 585–591 | Cite as

Age versus size determination of radial variation in wood specific gravity: lessons from eccentrics

Original Paper


Radial increases in wood specific gravity have been shown to characterize early successional trees from tropical forests. Here, we develop and apply a novel method to test whether radial increases are determined by tree age or tree size. The method compares the slopes of specific gravity changes across a short radius and a long radius of trees with eccentric trunks. If radial changes are determined by size, then the slope of the change should be the same on both radii. If radial changes are determined by age, then the slope should be greater on the short radius. For 30 trees from 12 species with eccentricity of at least 4%, the ratio of the slopes of the linear regressions of specific gravity on radial distance (short radius slope/long radius slope) was regressed on the ratio of radii lengths (long radius/short radius). The regression was highly significant, and the faster increase in specific gravity on the short radius was sufficient to compensate for the difference in radius lengths, so the specific gravity of wood along the short radius was equal to the specific gravity on the long radius at any given proportional distance on the radius. Therefore, trees that are producing xylem faster on one radius than another produce wood of comparable specific gravity on both radii at the same time, so radial increases in specific gravity are dependent on tree age, not tree size.


Costa Rica Tree eccentricity Radial gradients Tree age and size Wood specific gravity 


  1. Baker TR, Phillips OL, Malhi Y, Almeida S, Arroyo L, DiFiore A, Erwin T et al (2004) Variation in wood density determines spatial patterns in Amazonian forest biomass. Glob Change Biol 10:545–562CrossRefGoogle Scholar
  2. Baker TR, Phillips OL, Laurance WF, Pitman NCA, Almeida S, Arroyo L, DiFiore A et al (2009) Do species traits determine patterns of wood production in Amazonian forests? Biogeosciences 6:297–307CrossRefGoogle Scholar
  3. Brown S, Lugo AE (1992) Aboveground biomass estimates for tropical moist forests of the Brazilian Amazon. Interciencia 17:8–18Google Scholar
  4. Butterfield RP, Crook RP, Adams R, Morris R (1993) Radial variation in wood specific gravity, fiber length and vessel area for two Central American hardwoods: Hyeronima alchorneoides and Vochysia guatemalensis: natural and plantation-grown trees. IAWA Bull 14:153–161Google Scholar
  5. Castro F, Williamson GB, Moraes de Jesus R (1993) Radial variation in the wood specific gravity of Joannesia princeps: the role of age and diameter. Biotropica 25:176–182CrossRefGoogle Scholar
  6. Chave J, Andalo C, Brown S, Cairns MA, Chambers JQ, Eamus D, Fölster H et al (2005) Tree allometry and improved estimation of carbon stocks and balance in tropical forests. Oecologia 145:87–99PubMedCrossRefGoogle Scholar
  7. Chave J, Coomes D, Jansen S, Lewis SL, Swenson NG, Zanne AE (2009) Towards a worldwide wood economics spectrum. Ecol Lett 12:351–366PubMedCrossRefGoogle Scholar
  8. Fearnside PM (1997) Wood density for estimating forest biomass in Brazilian Amazonia. For Ecol Manage 90:59–87CrossRefGoogle Scholar
  9. Keeling HC, Phillips OL (2007) The global relationship between forest productivity and biomass. Glob Ecol Biog 16:618–631CrossRefGoogle Scholar
  10. Malhi Y, Wood D, Baker TR, Wright J, Phillips OL, Cochrane T, Meir P et al (2006) The regional variation of aboveground live biomass in old-growth Amazonian forests. Glob Change Biol 12:1107–1138CrossRefGoogle Scholar
  11. Nock CA, Geihofer D, Grabner M, Baker PJ, Bunyavejchewin S, Hietz P (2009) Wood density and its radial variation in six canopy tree species differing in shade-tolerance in Western Thailand. Ann Bot 104:297–306PubMedCrossRefGoogle Scholar
  12. Nogueira EM, Nelson BW, Fearnside PM (2005) Wood density in dense forest in central Amazonia, Brazil. For Ecol Manage 208:261–286CrossRefGoogle Scholar
  13. Nogueira EM, Fearnside PM, Nelson BW, Franca MB (2007) Wood density in forests of Brazil’s ‘arc of deforestation’: implications for biomass and flux of carbon from land-use change in Amazonia. For Ecol Manage 248:19–135CrossRefGoogle Scholar
  14. Nogueira EM, Fearnside PM, Nelson BW (2008a) Normalization of wood density in biomass estimates of Amazon forests. For Ecol Manage 256:990–996CrossRefGoogle Scholar
  15. Nogueira EM, Fearnside PM, Nelson BW, Barbosa RI, Imbrozio BE, Keizer WH (2008b) Estimates of forest biomass in the Brazilian Amazon: new allometric equations and adjustments to biomass from wood-volume inventories. For Ecol Manage 256:1853–1867CrossRefGoogle Scholar
  16. Poorter L, Wright SJ, Paz H, Ackerly DD, Condit R, Ibarra-Manríquez G, Harms KE et al (2008) Are functional traits good predictors of demographic rates? Evidence from five neotropical forests. Ecology 89:1908–1920PubMedCrossRefGoogle Scholar
  17. Rueda R, Williamson GB (1992) Radial and vertical wood specific gravity in Ochroma pyramidale (Cav. ex Lam.) Urb. (Bombacaceae). Biotropica 24:512–518CrossRefGoogle Scholar
  18. Whitmore JL (1973) Wood density variation in Costa Rican balsa. Wood Sci 5:223–229Google Scholar
  19. Wiemann MC, Williamson GB (1988) Extreme radial changes in wood specific gravity in some tropical pioneers. Wood Fiber Sci 20:344–349Google Scholar
  20. Wiemann MC, Williamson GB (1989a) Radial gradients in the specific gravity of wood in some tropical and temperate trees. For Sci 35:197–210Google Scholar
  21. Wiemann MC, Williamson GB (1989b) Wood specific gravity gradients in tropical dry and montane rain forest trees. Am J Bot 76:924–928CrossRefGoogle Scholar
  22. Williamson GB, Wiemann MC (2010a) Measuring wood specific gravity…correctly. Am J Bot 97:519–524PubMedCrossRefGoogle Scholar
  23. Williamson GB, Wiemann MC (2010b) Age-dependent radial increases in wood specific gravity of tropical pioneers. Biotropica 42:590–597CrossRefGoogle Scholar
  24. Wright IJ, Ackerly DD, Bongers F, Harms KE, Ibarra-Manriquez G, Martinez-Ramos M, Mazer SJ et al (2006) Relationships among ecologically important dimensions of plant trait variation in seven neotropical forests. Ann Bot 99:1003–1015PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag (outside the USA) 2010

Authors and Affiliations

  1. 1.Department of Biological SciencesLouisiana State UniversityBaton RougeUSA
  2. 2.Center for Wood Anatomy Research, USDA Forest Service, Forest Products LaboratoryMadisonUSA

Personalised recommendations