150 /. y. Kotze 



(3) Climate. 

 Temperature. 



In high-lying areas frosts, especially early frosts, are a serious 

 factor to reckon with in the establishment of plantations of cer- 

 tain species, such as the Eucalyptus. In normal years, if the 

 selection of species has been sound, losses are insignificant, but 

 occasionally sudden severe frosts, accompanied by cold winds, 

 following on a period of warm weather, will play havoc. In 

 such circumstances the whole or a large percentage of the plan- 

 tation may be destroyed, though, if the planting scheme be perse- 

 vered in, and is favoured with a few good seasons, a wood may 

 be established which will be proof against subsequent vicissitudes 

 of a similar kind. It is generally in the first two years after plant- 

 ing that losses occur. Aftei that the trees are usually strong 

 enongh to hold their owti. 



JR.amfall. 



Perhaps no factor in South Africa influences afforestation so 

 much as rainfall, and it is owing to the more abundant precipi- 

 tation that the most suitable portions of the country for affore- 

 station occur along the escarpment previously referred to and on 

 the foohhills immediately below it. 



Where the fall drops to below 20 inches the limit of successful 

 commercial forestry may, speaking broadly, be said to have been 

 reached. In the dry western and central interior portion of the 

 Cape Province where the rainfall is about 5 to 1 5 inches, tree 

 growth, except along river banks, is entirely absent, and it is im- 

 practicable, if not impossible, except under irrigation, to establish 

 plantations in such localities. 



Attention must be drawn to the variation that occurs in the 

 Cape Province in respect of the time of the year during which 

 the rain falls, for this variation has a marked influence in the 

 selection of the species of trees suitable for a particular locality 

 A tree such as Pinus lonsifoUa is peculiarly suited to a summer 

 rainfall area, whereas P.insignis, although largely grown in sum- 

 mer rainfall areas, shows better and surer growth in winter or all* 



