ORIGINAL PAPER Assessing the utility of direct and indirect methods for estimating tropical tree age in the Western Ghats, India Cheryl D. Nath • Anaı ¨s Boura • Dario De Franceschi • Raphae ¨l Pe ´lissier Received: 10 September 2011 / Revised: 4 January 2012 / Accepted: 5 January 2012 / Published online: 25 January 2012 Ó Springer-Verlag 2012 Abstract The knowledge of tree age is important for understanding tree growth and forest dynamics. It may be estimated by ‘direct’ methods involving growth ring counts, or by ‘indirect’ methods involving field measure- ments of growth rates. Direct methods are considered more accurate, but it is not clear if they are appropriate for all species, notably from the humid tropics. In this paper we assess the occurrence of annual growth rings and their utility for age estimation in three tropical tree species, Acrocarpus fraxinifolius, Dalbergia latifolia (Fabaceae) and Syzygium cumini (Myrtaceae), growing in traditional shade coffee plantations of the southern Western Ghats, India. These species previously were described as having ‘‘indistinct or absent’’ growth rings. We used anatomical studies, field measurements and computational methods to characterise growth rings and assess similarities between directly and indirectly estimated tree ages. Our study revealed that annual growth rings were characterised by different sets of anatomical features per species and were most distinct in the fast-growing deciduous A. fraxinifolius. Growth rates measured in the field showed annual peri- odicity in all three species, and reflected annual rainfall- drought cycles in D. latifolia and S. cumini. Direct age estimates were most similar to indirect estimates in D. latifolia, and least so in S. cumini. The results of direct age estimation by counting rings are consistent with them being annual in nature in tropical species with distinct and reliable annual growth ring formation. However, for spe- cies with poorly defined growth rings, indirect age esti- mation methods might be more useful. Keywords Age-size trajectories Á Drought Á Growth periodicity Á Kodagu Á Loess Á Stochastic model Introduction Establishing the relationship between age and size of trees is an important problem for forest ecology and conservation (Ashton 1981; Brienen and Zuidema 2006; Lieberman et al. 1985; Martı ´nez-Ramos and Alvarez-Buylla 1998; Metcalf et al. 2009; Terborgh et al. 1997; Vetter and Botosso 1989). It also is of interest for silviculture and plantation manage- ment (e.g., Nath et al. 2011; Sa ´nchez-Gonza ´lez et al. 2005; Scho ¨ngart 2008). Methods for establishing tree age have been classified as ‘‘direct’’ or ‘‘indirect’’ (sensu Martı ´nez- Ramos and Alvarez-Buylla 1998). Direct methods involve exact age determination by methods such as cohort moni- toring, counting growth rings or palm frond scars, X-ray densitometry, radiocarbon dating and isotopic composition, Communicated by S. Leavitt. C. D. Nath (&) Á R. Pe ´lissier French Institute of Pondicherry, UMIFRE 21/USR 3330, CNRS-MAEE, 11 St. Louis Street, Pondicherry 605001, India e-mail: cheryl.nath@ifpindia.org C. D. Nath INRA, UMR AMAP, 34000 Montpellier, France A. Boura Universite ´ Pierre et Marie Curie, UMR 7207 CNRS/MNHN/UPMC, MNHN, CP38, 57 rue Cuvier, 75231 Paris Cedex 05, France D. De Franceschi Muse ´um national d’Histoire naturelle, UMR 7207 CNRS/MNHN/UPMC, CP38, 57 rue Cuvier, 75231 Paris Cedex 05, France R. Pe ´lissier IRD, UMR AMAP, 34000 Montpellier, France 123 Trees (2012) 26:1017–1029 DOI 10.1007/s00468-012-0679-6