504 Forestry Quarterly 



An interesting biological evolutionary 

 Evolution history is observed in Norway in the fight 



of for supremacy between Norway spruce and 



Forest Scotch pine in Norway. 



Types The appearance of spruce (Picea excelsa) 



on leached deposits of sand and gravel, on 

 soils with a general deep water table, on land covered with dense 

 xerophytic moss and creepers among which is a species of Ground 

 pine, and upon other typical pine sites, has of late occasioned con- 

 siderable concern. It is, of course, true that such ground, which 

 offers little of the nourishment requisite for healthy spruce develop- 

 ment, cannot be the best sites upon which to grow this species; but 

 by closer observation, we shall find that in most such cases spruce 

 fills an important fimction for a longer or shorter period, especially 

 as a stand-forming tree giving protection on lands where pine is 

 foiind scattered and slow growing. This is, perhaps, more the case 

 on the first three kinds of site mentioned. We often make a serious 

 mistake when we, as the saying goes, want to polish up our stands, 

 by clearing away all small undergrowth in order to clear the forest 

 floor, without taking sufficient thought of the soil characteristics. 

 On the poorer sites, and particularly where there is danger of 

 drying out or an invasion of weeds, this treatment is imdesirable. 

 Every bush and twig should be preserved until the forest is ready 

 to be reproduced. 



On the moister pine lands one runs the risk that by allowing the 

 spruce to continue within the stand it will reach up and mix in the 

 upper crown space belonging to the pine, with the result that the 

 latter grows unnecessarily tall at expense of diameter growth. 

 Should the spruce be tolerated too long, it may drive the pine out 

 entirely. On moist sites within the pine type, therefore, it is best 

 to hold the spruce in check. Up toward timberline it becomes 

 necessary to employ the greatest care in the treatment of spruce. 

 Spike-topped trees with green limbs in open stands are omens 

 pointing to conservatism and a certain minimum density. In fact, 

 it is hardly ever good policy to cut in this upper belt. It is pretty 

 axiomatic that where pine will grow it should be most zealously pre- 

 served, and the same holds for spruce toward timberline. 



I feel quite certain that the general preference for pine on what 

 is considered pine land is largely responsible for the desire to get 

 rid of spruce there. It is justifiable to combat spruce at certain 



