IN CEYLON. 47 



attained the standard dimensions, and at such a rate that 

 only one-fortieth to one-sixtieth of the forest acreage under 

 his charge is cleared each year. 



The occurrence of ebony within the plant cannot be 

 stated in terms of the age of the tree, the dimensions of the 

 stem, or the climatic conditions under which the plants 

 have been grown, though a few facts capable of a very 

 general application may be here given. The black heart- 

 wood occurs usually in the stem, but is often present in 

 young twigs and roots. In the majority of our species the 

 discolouration commences in the perimedullary zone and 

 spreads from within outwards. The discolouration is usually 

 of an uniform black in D. Ebenum, streaked in IX oocarpa, 

 D. affirm^ D. quaesita and others, red in JD. Moonii, and a 

 dirty white in such species as D. msignis and D^attenuata. 

 The discolouration may occur in the oldest central wood 

 only, or it may appear in local strands throughout the 

 secondary xylem of the stem. In many young stems the 

 only areas where ebony has been produced are directly 

 associated with insect punctures, wounds, &c. 



The occurrence of the central black wood within the 

 length of the stem is often erratic, though most usually it- 

 decreases in volume from below upwards. 



The eccentric formation is where the central column of 

 black wood widens and narrows repeatedly at different points 

 along the stem, and in consequence of this one cannot 

 accurately estimate the volume of ebony in a stem by 

 external observations alone. In some instances; particularly 

 in young stems and twigs, the black heartwood repeatedly 

 dies away and reappears at different points along a given 

 length. 



The age of a particular tree or the dimensions it has 

 attained do not afford a sure criterion as to the quantity of 

 ebony it will possess, though the probabilities are that the 

 older the tree and the larger the dimensions, the greater 

 will be the proportion of discoloured heartwood. This 



