168 ARTIFICIAL FORMATION OF WOODS. 



rainfcill varial)le, seed may be sown both at tlie bottom of 

 the ditch and along one of the upper edges. In the case of a 

 scant}- rainfall the former will succeed, and in case of a wet 

 3'ear, the latter. 



The method is indicated in dvy hot localities, and where 

 irrigation is practicable. As it is expensive, it should be 

 adopted only in cases where a cheaper method is not likely to 

 yield satisfactory results. The pit method is cheaper than 

 trench sowing, but it frequently yields less favourable results, 

 and is not applicable where irrigation is contemplated. 



e. Sotriiifi on Kiihjes and MouikIs. 



This method is the reverse of the one described under d. 

 It is advisable in the case of wet or heavy soil, the object 

 being to raise the seed bed above the water level, and to expose 

 the soil to a more complete action of the air. Mounds are 

 interrupted ridges, just as patches are interrupted strips. The 

 ridges or mounds are formed, either by drawing together the 

 surface soil, or better by excavations. In the case of ridges 

 the ditches run along either one or both sides ; in the case of 

 mounds the earth may be taken from an excavation on one 

 side, or from a trench surrounding the mound. 



Where a moderate elevation suffices, parallel ditches may 

 be dug, and the excavated earth spread evenly over the inter- 

 mediate spaces, thus forming elevated platforms on wliicli 

 the seed is sown. See Fig. 19 on page 187. 



The seed should be sown densely and not too early in 

 spring, so as to allow a portion of the moisture to evaporate 

 before sowing. The tools used are the same as for trench or 

 pit sowings. 



The method is expensive and only indicated in exceplioiuilly 

 unfavourable localities. 



/. ('onthindHdiif'. 

 It happens not unfre(|U('ntly. that two or more of the 

 different methods ar(; combined in tlio same locality. Such 

 fonibiiiations are indicated when the character of the locality 



