ACACIA 



459 



This shows rapid growth, and as the rings were perfectly distinct the 

 figures may be regarded as accurate. The diameter of heartwood averaged 

 0-67 of the whole diameter including bark. 



Proportion of heartwood. The following measurements by Mr. A. Rodger 

 of about 100 sections of cutch trees in the Thayetmyo and Prome districts 

 of Burma show that the percentage of heartwood increases with size : 



Acacia Catechu : measurements of heartwood in trees of different sizes. 



4. Acacia modesta, Wail. Syn. Mimosa dumosa, Roxb. Vern. Phtdai, 

 Punjab. 



A moderate-sized thorny tree with a bushy rounded crown and drooping 

 branchlets. Bark rough, with numerous irregular cracks. Sap wood large, 

 white : heartwood very hard, dark brown with black streaks, not durable, 

 used for cane-crushers, Persian wheels, and agricultural implements, and 

 largely for fuel. The tree is useful for afforestation purposes on poor stony 

 soil in the dry lower hills and plains : it also makes a good hedge plant if 

 trimmed. 



This tree occurs more or less gregariously in the dry outer hills and valleys 

 of the Suliman Range, ascending to 4,000 ft. in the Salt Range, the sub- 

 Himalayan tract from the Jumna westwards, ascending to 4,000 ft., the 

 northern part of the Punjab plains, and Baluchistan. In Hazara it is common 

 on limestone in the scrub forests of Khanpur, and occurs in the Kagan valley 

 on hot shaly hill-sides up to 5,500 ft. Within its natural habitat the rainfall 

 varies from 15 to 50 in., the absolute maximum shade temperature may rise 

 to over 120 F., and the absolute minimum may sink to well under freezing- 

 point. 



It is found on various geological formations, including limestone, sand- 

 stone, conglomerate, and shale, and is capable of growing in poor dry shallow- 

 soil where few other species can survive. It may occur pure or in mixture 

 with other trees. Among its commoner associates are Oka cuspidata, Acacia 

 Catechu, Flacourtia Eamontchi, Tecotna undulata, Prosopis spicigera, Bauhinia 

 variegata, Odina Wodier, Zizyphus Jujuba, Ehretia laevis, and other miscel- 



