Timber: Classification of Trees

 Depending upon their mode of growth trees may be divided in the following two categories 

(i) Endogeneous trees:

 These trees grow inwards and fibrous mass is seen in their longitudinal sections. Timber from these trees has very limited engineering applications Ex: bamboo, cane , palm  etc 

(ii) Exogeneous trees:  

These increases in bulk by growing outwards and used for engineering purposes. Exogeneous trees are further sub divided into two groups   

      a) Conifers or evergreen trees:

These trees having pointed, needle like or scale like leaves and yield soft wood

        b) Deciduous trees: 

The trees having flat broad leaves and leaves of those trees fall in autumn and new ones appear in spring season. Timber for engineering purpose is mostly derived from  deciduous trees. These trees yield hard wood. 

Eg.. ash, beach, oak, sal, teak, shishum and wallnut