Use of Wood Characters in the Identification of Terminalia spp in Sri Lanka

Abstract

More than 250 timber species are being used by the timber industry in Sri Lanka, among themajor timber consumers are housing developer, furniture manufacturer and wood fabricators.Once the tree is felled, the identification of the tree become very difficult and need to rely ontheir macroscopic/ microscopic features and physical properties of timber. Timberidentification is necessary for right use of timber and to check on fraud in timber trading assome timber traders mix or sell low price, different type of timber species, deceivingcustomers to increase their profit margin.

Five timber species of Terminalia namely Terminalia arjuna (Kumbuk), Terminalia bellirica(Bulu), Terminalia catappa (Kottamba), Terminalia chebula (Aralu) and Terminaliaparviflora (Hampalanda) of the family of Combretaceae were studied anatomically in searchof sufficient features by which one Terminalia sp can be separated from the other . Theexamination of the transverse section of wood with a hand lens (x25) does not provideadequate reliable information to differentiate one species from the other for identification dueto resemblance of wood structure of five Terminalia spp. Hence for the anatomicalexamination, transverse section (T.S.), radial longitudinal section (R.L.T.) and tangentiallongitudinal section (T.L.S.) were obtained using the microtome.

In this study, some important wood anatomical and non anatomical features were studiedaccording to IAWA (1989). It was found that all the Terminalia spp had diffuse porous woodhaving vessels mainly solitary and occasionally in 2 -3 vessels of radial multiples. Meanvessel diameter and vessel diameter range were recorded respectively as 241 μm and 172-331 μm in Terminallia arjuna, 169 μm and 107-204 μm in Terminalia bellirica , 240 μmand 169-309 μm in Terminallia catappa, 115 μm and 68-175 μm inTerminalia chebula and124 μm and 75-159 μm in Terminalia parviflora. Mean vessel frequency were observed as 3per mm2 in Terminallia arjuna, 4 per mm2 in Terminalia bellirica , 3 per mm2 inTerminallia catappa, 6 per mm2 in Terminalia chebula and 5 per mm2 in Terminaliaparviflora. Mean rays frequency, mean ray height and mean ray width were foundrespectively as 9 per mm, 206 μm, 24 μm in Terminallia arjuna, 11 per mm, μm 283, 24μm in Terminalia bellirica, 8 per mm, 280 μm, 25 μm in Terminallia catappa, 13 per mm,239 μm, 31 μm in Terminalia chebula and 10 per mm, 235 μm, 30 μm in Terminaliaparviflora. Ray cell arrangement is mostly uniseriate and occasionally byseriate inTerminalia bellirica, Terminalia parviflora, Terminallia arjuna. Ray cell arrangement ismostly multiseriate and occasionally uniseriate in Terminallia catappa. Terminalia chebulahas uniseriate ray cell arrangment.

Different type of axial parenchyma types were found in each terminalia species from whichthe prominent type of axial parenchyma was identified from each species as follows;Terminalia bellirica had axial parenchyma band (more than three cells wide). Terminalia parviflora and Terminalia catappa had aliform/ vasicentric type axial parenchyma which canbe differentiated from confluent parenchyma type in Terminalia chebula. Vasicentric (halo)parenchyma typewere found mainly in Terminallia arjuna. Finaly, it can be concluded thatray cell arrangement and axial parenchyma types can be used together as baseline todistinguish Terminalia spp in Sri Lanka for the purpose of timber identification.