204 SYLVICULTURE IN THE TROPICS *r. n 



ing^, and the onlv case in which the method can be 

 followed advantageously, provided there is sufficient 

 demand for the material, is when a bamboo forest seeds 

 gregariously, as happens with several species of 

 bamboos. 1 All the clumps die after seeding, and if the 

 culms can be cut down and removed, not only does the 

 young crop of seedlings get a better chance of coining 

 up, but a very considerable danger from fire is also 

 removed. 



(ii.) The aim of the method of cleared lines is to 

 remove some of the dangers appertaining to the method 

 above described by giving side shelter to the coupes, and 

 by making them so narrow that seed from the standing 

 crop may be easily distributed all over the area. 



The fellings are made in narrow strips cleared 

 through the forest, corresponding strips of standing 

 forest being left untouched between successive coupes. 

 The cleared strips are made of a width which is 

 usually not much greater than the height of adjoin- 

 ing forest trees ; while the width of the strips left stand- 

 ing is either the same as that of those which are cleared, 

 or a multiple of that width in places which are much 

 exposed to violent winds or to erosion. 



The direction given to the strips is governed by the 

 direction of the prevailing winds, especially of those 

 prevailing at seed-time, by the configuration of the 

 ground, and by the course of the sun. 



As regards the wind, it is most advantageous to cut 



1 It must be confessed, however, that sometimes Nature has a way of laugh- 

 ing at the obstacles which delay natural regeneration in large open spaces. In 

 Ajmere the mere closing of certain areas to grazing and preservation against lire 

 has led to the springing up of forest growth, part of which was no doubt from 

 stool-shoots or root-suckers which had been annually killed down to the ground 

 level. But in the Sudan, in the Province of Dongola, the riparian lands of which 

 along the Nile had been subjected to a high degree of cultivation, the inva- 

 sions of the hordes of the Mahdi and Khalifa cleared the country of population 

 and herds, and left the ground untilled. Here, although the rainfall is not above 

 1 in. per annum, all the arablo lands got covered with a dense growth of Acacia 

 ardbica and ./. Seyal, and this was the condition they were found in when the 

 British and Egyptian troops again took the country. The same thing happened 

 in parts of the Berber Province and near the upper Blue Nile, where the rain 

 cropa were cultivated Borne way inland: the population was sent away to 

 Omdurman, and the fallow Gelds, many square miles in extent, got covered with 

 an almost pure forest of Acacia Seyal. 



