34 



37. THE BAMBOO. Arundinaria alpina, the bamboo of Kenya Colony, 

 grows gregariously, forming extensive tracts at an altitude of 7,500 to 

 10,000 ft., occasionally descending lower or ascending higher : it appears to 

 thrive best between 8,000 and 9,500 ft. There are no rainfall statistics within 

 the bamboo zone, but the rainfall within this zone is probably for the most 

 part between 40 and 75 in. In its early stages the bamboo forms loose clumps, 

 but these soon spread until there is no further sign of clumps, the bamboo 

 covering the ground in a continuous growth of separate culms, which in a 

 dense crop may be as close as 2 ft. apart on an average. The culms, which 

 attain a height of 30 to 60 ft. with a diameter of 2 to 4 in. or occasionally 

 more, are hollow, with walls 0'4 to 0-7 in. thick. 



38. FLOWERING OF THE BAMBOO. Certain species of bamboo flower 

 gregariously over extensive areas at long intervals of time; the old culms 

 then die and a new generation springs up from seed and takes many years to 

 produce full-sized culms once more. In such an event, a pulp factory would 

 stand a strong risk of being thrown out of work for several years. It is 

 important, therefore, to know whether there is any chance of such a gregarious 

 flowering in the case of the East African bamboo. A study of conditions in 

 several bamboo tracts leads me to the conclusion that there is little risk of a 

 gregarious flowering of such an extent as to necessitate the temporary closing 

 of a factory. This conclusion is based on the fact that the bamboo is always 

 flowering in patches of varying extent.and patches of different ages, produced 

 by sporadic flowering in past years, are constantly met with : this being so, 

 it is unlikely that an extensive gregarious flowering will occur which will 

 embrace those areas where flowering has already taken place within recent 

 years. 



39. YIELD OF BAMBOOS. Measurements of clear-felled plots carried 

 out by the Forest Department in different bamboo areas gave the following 

 figures : 



Number of culms per acre, average 5,030 



maximum 7,750 



minimum 3,000 



Serviceable length, average 37 ft. 



maximum 50 ft. 



minimum 20 ft. 



Diameter average 2'5 in. 



maximum 4'3 in. 



Weight, green culms, 25-65 Ibs., average about 40 Ibs. 



dry culms, average about 20 Ibs., giving about 112 culms 

 to the ton. 



40. YIELD OF PULP. Laboratory experiments at the Imperial Insti- 

 tute gave 37 per cent, of air-dry pulp (expressed on air-dry bamboo) when 

 treated with a solution of caustic soda. Manufacturing trials by a firm of 

 paper manufacturers at the request of the Imperial Institute, in which the 

 bamboo was treated by the soda process, gave pulp which bleached well and 

 yielded white paper of good quality. Knots were not removed. The yield, 

 including loading and size, was 41'23 per cent, of the weight of the bamboos, 

 which is considered satisfactory. 



41. EXPLOITATION OF BAMBOOS. If a bamboo area is repeatedly clear- 

 felled at comparatively short intervals the culms deteriorate in number and 

 size and the bamboo may eventually be exterminated. In India, the usual 

 custom is to fix a rotation of about 4 years, but to prohibit the felling of any 

 culms of the last season's growth. In the case of the East African bamboo, 

 if worked on a large scale, clear felling would be more practicable than par- 

 tial felling of this kind, and as far as my observations go, the effect does not 



