ACACIA 



457 



scanty. Measurements in Bhandara, Central Provinces, in 1912-13 showed 

 the average height of coppice-shoots one }ear old to be 6 ft. 4 in. as against 

 7 ft. 1 in. for teak and 6 ft. 6 in. for Terminalia tomentosa. Measurements 

 recorded by Mr. A. F. Broun at Bulla wala near Dehra Dun in 1886 showed 

 an average girth of 8 in. and an average height of 11 ft. 4 in. for coppice 

 nine years old. 



High forest. The annual rings are usually, but not always, quite distinct, 

 and the rate of growth can thus as a rule be deduced from ring-countings. 

 Measurements show the growth to be extremely variable. Gamble says 

 Himalayan specimens show 5 rings per inch of radius, giving a mean annual 

 girth increment of 1-26 in. ; a specimen from the bed of the Mahanadi, Dar- 

 jeehng tarai, showed 3-8 rings per inch of radius, giving a mean annual girth 

 increment of about 1-7 in., which is fast. 



Extremely slow growth is shown in an unthinned riverain sample plot 

 of kJiair mixed with Dalbergia Sissoo in the Saharanpur Siwaliks in a somewhat 

 dry locality with a soil of sand and boulders. The measurements, which 

 applied to forty-five trees and extended over five years only (1910-11 to 

 1915-16), gave the following results : 



Acacia Catechu : girth increment in unthinned sample plots, Siwaliks, 



United Provinces. 



Although these results can hardly be regarded as very accurate owing 

 to the short period over which the measurements extended and to the fact 

 that dominated and suppressed trees were included, they emphasize the 

 importance of carrying out regular thinnings to promote more rapid growth. 

 A somewhat faster rate of growth is shown in an unthinned sample plot 

 in the Sathiana block of the North Kheri forests. Measurements, which 

 extended over eight years and related to seventy-five trees, gave the following 

 results : 



girth increment in unthinned sample plot, Sathiana block, 



This plot was situated within the limits of the sal forests, not on recent 

 alluvium. 



