264 Journal of the Department of Agriculture. 



judgment ii) the conducting of tliiuuings may not be eradicated 

 throughout the rotation of a crop. 



Choice of Species. 



As ilie bullv of tlie timbering in the mines is required to last 

 only a few years, durability is not essential. A low grade quality 

 of timber can therefore be used, provided it is sufficiently straight. 

 Advantage is taken of this circumstance to plant ihe most rapid 

 growing species without consideration as to durability. A certain 

 amount of strength is, however, necessary, and experience goes to 

 show that in this respect Eucalyptus coriacea, when grown on the 

 high veld, fails to come up to the required standar/t. AYith this 

 exception, and a few othei's tliat will be referred to later,' the choice 

 of species is mainly limited by soil and climatic conditions. 



To meet the above requirements, the following are the principal 

 species used, viz.. Eucalyptus niminalis, Euc. rostrata, Euc. Maidenii, 

 Euc. glohidus, and Euc. sidero.rylnn . The requirements of each are 

 discussed in detail hereunder. 



Syliviculttjr.4l Notes. 



The following notes apply only to the species above referred to 

 under the coiidilions to be met with on the high veld, and must not 

 be taken as applicable to all j)arts of the country. 



E%( ca lyp i u s v im ina lis . 



This i.s the favourite tree on account of its rapid growth and 

 hardiness to frost, though not quite immune in exceptional seasons 

 or in bad frost hollows. It is sensitive to drought on shallow soils 

 and on lands infesied with quick grass, but hardy enough on deep, 

 clean soil. It should be safe on 6 feet or more of soil where the 

 rainfall ranges from 24 to 30 inches. The lower the rainfall the 

 greatei- the depth of soil required. Sub-soil is included in the 

 expression "depth of soil," provided it is sufficiently porous for 

 moisture and roots to i)enetrate. This tree may flourish for some 

 years even in shallow soil, but is then liable to fail suddenly when 

 the limit of moistiire is reached. A planting espacement of G feet 

 by 6 feet (1210 to the acre)' is, as a rule, the safest. In good condi- 

 tions a light thinning or cleaning may be required in the fourth or 

 fifth year. Thir.nings have to be repeated at intervals up to the 

 tenth of twelfth year. Light and frequent thinnings are the best, 

 but much depends on the seasons experienced, the frequency and 

 degree being regulated accordingly. The final stand suitable for 

 ]nine props is reached at the age of twelve to fifteen years in favour- 

 able circumstances, and should then consist of approximately 450 

 to 500 trees to the acre, averaging 8 to 12 inches in diameter at 

 breast height. The first cleaning will produce mosth'- laths and 

 ■ sticks. Later on lagging, sprag's, and firewood will be got, and, still 

 later, a percentage of props will be included in the thinnings. The 

 following table may be used as a rough guide for thinning a stand 

 of Eucalyptus viviinalis in a good situation with a planting espace- 

 ment of 6 feet by 6 feet intended f oi' props : — 



Original stand 1210 trees per acre. 



Fourth to fifth year thin to ... 900 

 Fifth to sixth year thin to ... 750 ,, ,, . 



Sixth to seventh year thin to... 600 ,, ,, 



Spventli +0 eightli vear Ihin to 500 ,, ., 



