62 



PKESIDKXTIAL ADDKESS SECTIOX C. 



up, tile rate ot (lesiccation vaiyino- with the difierences of 

 locality, soil and o-radients, and that sneh parts must sooner 

 or later become useless and uninhabitable it the process 

 proceeds unchecked." I o-o further than that, and sa.y that 

 the progress of desiccation is constantly contaoious, and that 

 if " many parts of the Fnion." as stated by the Committee, 

 are drying- up and will in time become useless and 

 uninhabitable, then the fate of the balance is sealed unless 

 active stei)s are taken to turn the tide. 



C'OXCLUSIOXS. 



Let us now draw together all these scattered threads and 

 show how man can aii'ect even the results of the cycles, 

 iiy maintaining the eastern grass-veid unburued, by maintain- 

 ing the forests or replacing them by exotic species of more 

 rapid growth and of greater transpiration, and by vastly 

 increasing' the area under such exotic trees, especiallj^ in the 

 grass-veld slopes and in the natural tree or scrub lands and on 

 the mountains, the amount of saved and redistributed moisture 

 is increased enormously, and so can be precipitated and again 

 absorbed time after time until the mountain faces are clad 

 with forest verdure and the overberg districts can share in 

 the surplus to the extent of enjoying a higher relative 

 humidity, a better vegetation, a more temperate method of 

 rainfall, and consequently less erosion than at present. 



On the other hand, by continued grass burning, forest 

 destruction, over-stocking veld tramping, bad agriculture, 

 water concentration and donga formation practically all rain 

 that falls is drained off immediately, and so has a local detri- 

 mental effect. There is very little redistributed moisture, and 

 that little becomes less year by year ; what moisture is 

 redistributed is insufficient to be redistributed many times, 

 and in consequence mostly does not reach the summit of the 

 escarpment, so that there are less mountain mist and rain, 

 less alpine swamp, fewer and smaller mountain springs and 

 mountain streams, less water running regularly in the streams 

 running either east or west, less overberg cloud, less actual 

 humidity overberg, less drizzle and soaking rain, more destruc- 

 tive storms and hailstorms, and more erosion. 



This is not an imaginary picture of what is possible. It is 

 a statement of what is happening now. and I have not the 

 least doubt but that grass burning and bush burning elsewhere 

 have a similar effect to that produced l)y fires on the eastern 

 slopes. 



But carry this further. We know from long experience 

 that we have recurrent alternate periods of drought and of 

 moisture. We have reason to believe that these occur here, 

 as elsewhere, in cycles more or less intimately connected with 

 sunspot phenomena which themselves are quite beyond our 

 control, and are known to have come at more or less regular 

 intervals during the nast 2,000 years, and presumably for very 

 many times before that period, so that there is no prospect 

 of their discoutinnance. We have shown that protection aiyl 

 extension of the forest and grass-veld produces better climatic 



