98 JOURNAL OF FORESTRY 



to a depth of 15 to 17 cm. Deeper loosening should be avoided to pre- 

 vent the formation of too long or weak roots. 

 The advantages of lime as a fertilizer are: 



1. Lime favors bacterial life in the soil, thus promoting the change of 

 insoluble combinations into forms which are available to the plants. 



2. It encourages root-growth. 



3. It improves the physical properties of the soil. 



4. It promotes the absorption of free nitrogen from the air. 

 Lime may be applied in the form of burned lime, slacked lime, and 



powdered limestone. The first two have a caustic efifect and should 

 not be applied in the spring before sowing, but the preceding fall, so 

 that the germinating seed and young plants will not be injured. Pow- 

 dered limestone, on the other hand, is mild in its effect and can be ap- 

 plied immediately before sowing. "In the liming of woods soil, as in 

 the cultivation of farm land, it should be taken into consideration that 

 as a consequence of liming the soil elements are more readily changed 

 into nutrients or, in other words, used up faster. Therefore, especially 

 poor soils should be manured at the time of liming, the manure being 

 first worked into the soil." 



The fertilizing effect of ashes, turf and mire soils, and coal dust, and 

 the ameliorating influence of sand are touched upon. 



Spacing in Planting and Direct Seeding 



Among the advantages of a closed stand over an open one are : 



1. The ground is shaded earlier and protected from drying out and 

 underbrush. 



2. The trees develop a better form. 



3. The resulting natural selection produces a stand of the strongest 

 individuals. 



Since the cost of planting increases as the spacing interval decreases, 

 "in Norrland, with its long distances, shortage of labor, and high day- 

 wage, higher than in the rest of Sweden, it is necessary to use as roomy 

 a spacing as possible, without risking either the ground's or stand's 

 welfare." 



Pine, spruce, and fir do not profit by the same spacing. The former 

 early differentiate themselves into crown classes and a culling or thin- 

 ning may be long postponed, with relatively little risk. Spruce and fir 

 develop very uniformly, and unless thinned the individuals soon hold 

 each other back in growth to the detriment of all. Open-spaced pine 

 does not protect the soil as well as similarly spaced spruce-fir. The 

 latter need a more open spacing to make it windfirm. The investiga- 



