Xylology and dendrochronology of tropical Indian trees
Funding Agency(ies):
French Institute of Pondicherry, CNRS – USR 3330 (France), Rufford Foundation (UK)
Principal Investigator(s):
Dr. Cheryl D. Nath
Start Date : 
Xylology and dendrochronology of tropical Indian trees
Axis 1. of the Ecology Department /

The study of wood anatomy, Xylology, and the scientific dating of tree growth rings, Dendrochronology, are techniques used in this lab to obtain insights into the development, growth and survival of trees. In the context of forest dynamics, these techniques provide a historical dimension to our understanding of community structure, disturbance patterns and climatic impacts. Ecological studies based on information available in wood are uncommon in India, especially for tropical tree species.

Estimation of tree age is another topic of interest, as it improves our understanding of life history strategies, community turnover and carbon sequestration, and has applied value for urban conservation and agroforestry. Given the paucity of such studies on tropical trees we need to first understand which species are most likely to produce distinct and datable growth rings.

Materials and methods:
Wood samples were collected from various Indian tree species, and we used a combination of field, laboratory and analytical techniques to characterize growth rings, assess tree growth and understand the drivers of growth-ring formation in tropical species.
Main outputs:

Growth rings were characterised in several south Indian species, and found to be distinct in approximately 30% of the samples. Field growth rates measured at three-month intervals for some species were annually periodic, reflecting local rainfall-drought cycles.

Tree age estimates obtained by direct examination of wood samples from species with distinct growth rings were similar to the corresponding, indirectly obtained computational estimates. However, for species with less distinct or absent growth rings, indirect estimates may be more reliable for assessing age.

Two functional characteristics, deciduousness and species maximum height, were identified by our research to be significantly associated with growth-ring distinctness in tropical Indian trees. Phylogeny did not generally influence growth-ring distinctness; however, in some cases it may constrain growth-ring distinctness at lower taxonomic levels, such as the genus level.
  • NATH C.D., MUNOZ F., PÉLISSIER R., BURSLEM D.F.R.P., MUTHUSANKAR G., 2016. Growth rings in tropical trees: role of functional traits, environment, and phylogeny, Trees, (in press, DOI 10.1007/s00468-016-1442-1)
  • SPEER J.H., [and 35 authors, including NATH CD], 2016. Pinus roxburghii stand dynamics at a heavily impacted site in Nepal: Research through an educational fieldweek, Dendrochronologia, DOI : 10.1016/j.dendro.2016.01.005.
  • NATH C.D., BOURA A., DE FRANCESCHI D., PELISSIER R., 2012. Assessing the utility of direct and indirect methods for estimating tropical tree age in the Western Ghats, India. Trees, 26: 1017–1029.