86 NATURAL REGENERATION 



tion a sufficient amount of light and at the same time it does not open up 

 the forest enough to allow weeds to come in (see Fig. 7, A to D). The 

 openings made are not quite so large as in the Scotch pine, because the 

 spruce does not demand the same amount of light. Frequently in spruce 

 stands the felling of one large tree makes an opening large enough to 

 favor the introduction of spruce seedlings, although usually two, three, 

 four, and even five trees may be cut [199]. 



A study of the spruce stand in the Savoie, by Thiollier (see Fig. 7), 

 showed that, on the whole, regeneration is difficult. In a wet, mild 

 climate, at lower altitudes, the spruce behaves much like the silver fir, 

 but at higher altitudes the spruce must be differently handled. To 

 secure spruce regeneration: 



(a) The seed must come in contact with fresh mineral soil, or soil 

 covered with humus of another species. If, for example, the ground is 

 covered with grass, or spruce litter, this must be worked and the soil 

 bared. 



(6) Isolated spruce saplings suffer from the snow, so every effort should 

 be made to secure clumps or groups for regeneration. 



(c) To secure thrifty, well-developed crowns, early and frequent thin- 

 nings are indispensable; but if too heavy the height growth is decreased, 

 the cover is broken, and the trees become branchy; if too light, or if begun 

 too late, the growth is slow and the trees are never really merchantable 

 for timber. 



(d) Since the spruce requires full sunlight for best development it is 

 best grown in even-aged clumps or stands. But since it is so liable to 

 windfall some form of selection fellings is desirable and necessary at these 

 altitudes. This shows the vital necessity of not practicing a selection 

 system by cutting single trees but rather groups of trees. These groups 

 are then developed by successive cutting into fairly even-aged stands. 

 Thiollier stated to the author personally that these three cultural rules 

 should therefore be followed : 



" 1. The young stands must always be kept dense; the thinnings should only remove 

 trees without a future and free the crowns of the best stems without ever opening up 

 the stand. 



"2. When a stand or a clump becomes of exploitable age, to regenerate it; make 

 openings (or holes) whose size varies with the altitude, the kind of soil, exposure, to be 

 made after an examination of existing blanks. 



"3. The soil cover (grass, brush, spruce litter) should be broken up by irregular seed 

 spots so as to form flat areas in the holes or blanks where the seeding should take place. 

 If regeneration fails, plant in the center (of openings) with at least five trees spaced 12 

 inches." 



In other words, Thiollier recognized the necessity of assisting natural 

 regeneration, and that the ground must not be allowed to run wild. 

 Since fir or beech is almost invariably mixed with spruce care must al- 



