DRY ZONE AFFORESTATION. 



107 



These small earthenware pipes, being very porous, soon perish, 

 and so everything possible to help the saplings can be considered 

 to have been done. The pit thus planted, being provided with the 

 subsoil watering contrivance above referred to, tends to favour deep 

 rooting, and this is the real secret of success in dry zone afforestation 

 works. 



The illustration showing the sectional diagram of a dry zone 

 planting pit with subsoil watering pipe (diagram p. 103) conveys as ac- 

 curately as can be described the work involved in an afforestation 

 scheme of this nature, viz. 70 main trees and 210 undergrowth or 

 280 nursery grown saplings to the acre. During the past two years 

 approximately 152 acres have been treated, which represents handling 

 of 42,650 saplings, everyone of them a pot- or pipe-grown plant. If 

 to this is added 8 to 10 per cent, for damage in transit (as each 

 sapling has to be carried across rocks to its position), it brings the 

 total from 45,965 to 46,821, including planting casualties. There 

 is also the inevitable mortality from stray animals, from prolonged 

 periods of drought when water is not available, and from such pests 

 as porcupines, hares, and rats, which are active during the dry season 

 and in the winter months. 



The mortality from all causes can be put down during the first 

 years at 25 to 30 per cent., which shows that a work of this description 

 could not be attempted without a nursery run on practical lines. 



The protective belt of Opuntia planted around each pit (fig. 10) 

 also involves a considerable amount of work, the bulk of the require- 

 ments having to be collected and brought from distances varying from 

 one to three miles. Unlike the Northern Ridge this site possesses 

 only a few stray specimens of the species, and to anyone who realizes 

 what it means to handle cart-loads of such prickly plants the magnitude 

 of the task will be apparent. 



Ravine Training to check Disintegration and Erosion. — The training 

 of ravines is another important factor in an undertaking of this kind ; 

 they are usually the result of the disintegration of the' rock caused 

 by the " run off," which again is the cause of the erosion that should 

 be brought under control as much as possible. There are, of course, 

 many points involved that govern the treatment to be applied ; in 

 some cases it may be almost impossible to devise a ravine training 

 scheme that would dispose of the "run off,' as the area actually 

 drained by a ravine has to determine the precautions to be taken. 



Some years ago, when the writer conducted the ravine training 

 scheme necessary for the making of the Macdonnel Park at Agra, 

 he was faced with earthen ravines varying between 100 to 250 feet 

 wide, and the scouring that annually took place undermined the adjoin- 

 ing land to such an extent that the sides became almost perpendicular. 

 Each storm gradually undermined the sides, and slices of earth would 

 get detached from the main body, temporarily blocking the outflow 

 and causing extensive damage, choking drains and culverts, and 

 sometimes cutting across metalled roads. 



