Heartwood assessment of natural Santalum album populations for agroforestry development in Sri Lanka

Sandalwood (Santalum album) is developing as an important agroforestry crop in Sri Lanka. The value of S. album depends upon the oil content in the heartwood and its composition with reference to sesquiterpene alcohols cis-α-santalol and cis-β-santalol. According to the popular belief in Sri Lanka, certain S. album trees do not produce oil even after maturity. Therefore the present study was conducted to identify the presence and the variation of essential oil, its composition and the variation of growth parameters of nine distinctive S. album populations growing under different agroecological zones in Sri Lanka. According to the results, heartwood content, oil content and its constituents varied within and between the populations. It was interesting to observe that cis-α-santalol and cis-β-santalol were not detected in certain S. album trees though the oil contents of those trees were higher than the average. Heartwood content of the trees did not show a correlation with oil content, dbh and height. However, the oil content was significantly correlated with tree dbh and height. Majority of the trees (62 %) had heartwood essential oil in compliance to ISO standards; only a 31 % of the total sampled trees had the essential oil content above 2 % (w/w). Dry mountainous Badulla district had the highest percentage of trees complying the ISO standards. These findings are vital for identifying suitable sources for agroforestry propagation of S. album.