12 



Sustaine.! workiug.— A forest so worked that tlie soil con- 

 -tinuously produces crops of wood from regeneration to 

 exploitation. 



Sylvieultural system.— A method according to which tluj 

 formation, regeneration, tending and exploitation of the 

 woods which compose a forest are effected. 



Systematic felling's.— rollings carried out according to 

 some recognised sylvicultural system. See Sylvicultural 

 -system. 



Transformation fellings.— Fellings carried out with a view 

 "to effecting a conversion of system. 



Two-storeyed forest.— The introduction of a second crop 

 (usually of shade-bearing species and generally by sowing 

 or planting) into an older crop, so that practically two 

 distinct high forests each of even-age exist on the same 

 area. The original crop forms " the upper tier or story " or 

 *' over wood "; the crop subsequently introduced " the lower 

 ±ier or storey." 



5. Relating to the sub-divisions of a forest. 



Blocli.— In order to arrive at the treatmeat required it is 

 :generally necessary to make a complete inventory and to 

 record the condition of the stock in the forest. To effect 

 this with any degree of accuracy, the area, if large, must be 

 •sub-divided into smaller portions, each of which would be 

 described separately. The sub-divisions chosen are, for 

 convenience and simplicity, generally natural, that is to say 

 either differing from one another in situation (for instance, 

 on the slopes of a hill-side or valley, or on opposite sides of 

 a river) or unlike in some permanent character of the 

 ■vegetation, as in tlie case of forests composed of different 

 species or occupying different classes of s^il, etc. The lines 

 of demarcation of such areas thus form the skeleton, so to 

 .speak, of the forest, and are permanent land-marks. Such 

 natural sub-divisions generally bearing local proper names 

 are included in the term blocks. 



It vpill, however, often happen in India that owing to the area not having already 

 been opened out such divisioni cannot be forme 1 without outtiug artificial lines 

 throngii the foreat, in such oases the management of llie forest under the working- 

 plan will necessitate the lajing put of new roads or piths for the eitraotion of the 

 pVodnce, and the lines along which it is proposed or considered likely that these new 

 noads will proceed should be utilised as the boundaries of tha blocks. 



