22 



should if possible be equal to the period and the revision period of the 

 plan, and the yield should be prescribed by area or out-turn, the usual safe- 

 guards as to minimum girth limit, etc., being applied. The opportunity 

 should be taken to free promising stems of valuable species from suppression 

 by stems of inferior species or others whose removal is desirable. 



It may be objected that anything in the nature of clear felling in hilly 

 country will result in the denudation of the hill-sides and interference with 

 the water-supply. In the case of large permanent clearings this objection 

 would be valid; but it is possible to arrange that no area felled in one place 

 should be so large as to cause any such risk, while in any case all cleared 

 areas would be planted up again without delay. 



22. APPLICATION OF SYSTEM TO DIFFERENT TYPES OF FOREST. 

 (1) Cedar forest. So far as can be foreseen it will be impossible to rely to 

 any appreciable extent on natural reproduction as a means of regenerating 

 cedar forests systematically. One fact is certain, namely, that in the great 

 majority of cedar forests of the best quality, where, owing to the fertility 

 of the soil, there is a heavy undergrowth, natural reproduction is for all 

 practical purposes absent. It is true that under certain conditions natural 

 reproduction appears in quantity, for instance, where the mineral soil has 

 been recently exposed, as in borrow-pits along the railway, and round the 

 edges of grass-lands bordering the forest. Again, in certain dry types of 

 cedar forest, where there is no dense low undergrowth, natural seedlings 

 may be found in quantity, particularly under the protection of m'lelishwa 

 and other bushes. Perhaps the best examples of cedar forest arising from 

 natural reproduction in the past are to be seen in the case of pure crops of 

 considerable extent resembling well-stocked plantations, on the western 

 slopes of the Aberdares and elsewhere. So far as can be ascertained, profuse 

 natural reproduction must have taken place as the result of a combination 

 of favourable factors, such as good seeding and timely and sufficient rainfall 

 following on a severe fire. It is more than doubtful, however, if such con- 

 ditions could be produced systematically with safety or success at a cost in 

 any way comparable to that at which artificial plantations of cedar can be 

 established with the aid of field crops. It is certain, therefore, that artificial 

 reproduction will have to be relied on for the great bulk of the regeneration, 

 and so far as can be foreseen at present the cheapest and most successful 

 method of regenerating will be by means of clear fellings followed by 

 artificial regeneration with the aid of field crops. Where the number of 

 cultivators is insufficient to secure complete regeneration by this means, a 

 subsidiary method, at present only in an experimental stage, may possibly 

 prove successful; this is by means of planting in lines 10 or 12 feet apart 

 cleared through the undergrowth and kept clear until the plants are free 

 from danger of suppression. 



Where healthy natural reproduction, whether of cedar, podocarpus or 

 other valuable species, already exists in sufficient quantity to dispense with 

 artificial reproduction, it should be taken advantage of where possible and 

 freed from suppression. In the case of cedar, however, this applies only 

 to masses of size and density sufficient to form a close crop of some extent ; 

 the retention of isolated saplings is not advisable in an area to be planted 

 up, since these will develop into branchy trees producing knotty timber and 

 interfering with the trees in the plantation. 



(2) Plateau forests. In the plateau (muhugu) type of forest consider- 

 able success has been attained by clearing round muhugu seed-bearers, the 

 result being a plentiful crop of natural reproduction of this important 

 species. It is possible, therefore, that much may be done by regeneration 

 fellings and cleanings. The cost of such work, however, should be carefully 



