28 About Trees, Shrubs and Climbing Plants for S.A. 



well grown, to the strongest winds. Again, the planting should 

 not make straight lines across the break, but should be diagonal, 



The minimum width thus occupied by the trees and their roots 

 will be about 24 feet, provided suitable types are chosen.* 



We need say nothing here about providing young trees, or pre- 

 paring the land. The processes are exactly the same as described 

 under " utility trees," and the time of planting the same. 



(4) Choice of Trees. 



The actual types or varieties of trees chosen for our purpose 

 will vary with soil, climate- aspect, &c., and these vary so very 

 much in South Africa that no man is capable of laying down 

 rules which are applicable to even small districts. This is a 

 point for careful enquiry, and your District Forest Officer will be 

 the man most likely to know best what to recommend. Get into 

 touch with him before choosing your trees, and follow his ad- 

 vice. 



Apart from this definite choice of varieties, however, there are 

 certain general requirements which the trees must meet for our 

 purpose, and these we may safely enumerate. Our trees must 

 have : 



Height, so that the area sheltered is as broad as possible. By 

 this we mean central height. 



Density, to effectually reduce the wind velocity. 



Quick groivth if possible. 



A good, root system, of a compact nature, so that the proxi- 

 mate crops are not robbed of nutriment. 



Hardiness, because a narrow belt of trees is much more exposed 

 to adverse conditions than a solid block in forest form. 



Long life, and with no tendency for odd specimens to die out 

 and leave gaps. 



The different varieties of Eucalyptus will give central height, 

 quick growth, hardiness, and a fairly long life ; and varieties may 

 easily be chosen to suit most conditions. But the root system of 

 a Gum is very spreading and greedy, and for this reason this 

 type should only be used to give height, preferably as a closely 

 planted single or double line. As they grow the lower branches 

 generally drop and leave a space through which the wind could 

 still sweep. Hence, with these it is necessary to use flanking 

 trees to fill up the base, preferably Coniferae, of which, the 

 Cypresses are probably the best. The root system of a Conifer 



More recent observation indicates that cypresses should be planted more 

 than 6 feet from gums, and that 8 feet would be better. 



