382 C. F. M. SWYNNERTON. 



very great many in any case — ^these, in secondary bush, could be treated with arsenite 

 by the owners themselves under the supervision of police, who might be sent round 

 with it for that purpose. This should render the clearing permanent — ^at a cost. 

 Surviving primary-forest stumps are killed by the grass fires after the cessation of 

 cultivation. 



(4). Clearing hy regulated burning. Of the probable good effect of this measure 

 I can speak with an assurance that is based on nearly twenty years of interested 

 observation and experiment ; interested, because my own land has been in question, 

 and I have had to study there the effect of early, late and no burning on pasture and 

 afforestation respectively. 



I have already (p. 325) contrasted the effect^'of early and late burning on thicket 

 and sapling growth. The following quotation is from a paper of mine, read in 191T 

 and published a year later, and written with no thought of tsetses in my mind, 



" The fact is," I wrote (S.A. Journal Sc, June 1918, p. 16), " that land from which 

 fire is excluded tends to go back to dense bush. Even the more open grass- veld here 

 is full of stumps that seldom get further than a one season's shoot. The very fires, 

 that have rendered their existence on that ground possible, by driving the [primary] 

 forest off it, keep them from growing up until, some year, a poor burn, it may be, or 

 no burn, allows of a second season's growth being superadded to the first and gives. 

 a more fire-resisting bark to the latter. . . . Keep the fire from such a piece of 

 ground — or burn too soon — ^f or several years, and these shoots grow up and eventually 

 in places become so dense as to reduce the grass and the severity of the fires and ta 

 allow semi-forest types as Markhamia lanata and Alhizzia chirindeyisis to spring 

 up amongst them, as I shall describe below, and eventually to replace them. The 

 result [even] when this occurs so far from high forest as not to obtain seeds from it, 

 is a form of dense thicket." On my o^vn land Uapaca-Brachystegia areas burned 

 regularly and more or less late have failed to develop appreciable undergrowth,, 

 while areas which, for winter grazing, have been burned irregularly and early, have 

 developed it (P] . xvii, fig. 2). The latter areas, which were clean-stemmed when I came 

 here,would now carry G. brevipalpis ; the former would not. Elsewhere in the irregu- 

 larly burnt area new coppice wooding has sprung up in open ground from long 

 suppressed underground stumps and roots and could already shelter pallidipes. 



The converse statement — ^that late fires will destroy already existent growi^h — is 

 true also. It is particularly true of a late fire following a year in which burning; 

 was omitted ; and I have sometimes been much struck — the last instance was late 

 in 1917 — by the large size of the p}T:ophytic saplings that such a fire has killed doAvn. 

 On occasions even large pyrophytic trees are definitely killed by it, at any rate in 

 such a season as 1913. Of the effect on primary-type thickets I have given an 

 instance on p. 325 and have seen further instances myself. 



With regard to the statement that late burning was a practice under the Zulu 

 regime, I can say from personal observation that there was less wooding, and less^ 

 undergrowth under existing wooding, in the Northern Mossurise district even when 

 I lived and travelled in it from eighteen to nineteen years ago than there is now after 

 a further period of unregulated burning. It is likely that this probable result of 

 their late burnings contributed much to the Zulus' success, particularly of late, in. 



