Be;rrv : Tree Growth and Seed 



133 



GROWTH HABIT OF THE NORWAY SPRUCE 



Important conclusions as to the effect of environment on seed are being drawn from a study 

 of the Norway spruce at Zurich, Switzerland, by Arnold Engler. It is found that seeds 

 collected from trees of normal, open growth reproduce this habit, while seed collected from 

 trees of stunted, twisted, or gnarled form tend to produce trees almost worthless for lumber- 

 ing purposes. It is also found that seed from high altitudes produces trees that have a 

 short growing season, even when planted in much lower altitudes. The importance of 

 seed selection thus becomes as great to the forester as it long has been to the gardener. 

 (Fig. 2.) 



growing season becomes a fixed char- 

 acter of tree growth; that is, that the 

 length of the period of active growth 

 varies directly with the mean tempera- 

 ture of the plant's habitat. Thus, the 

 plants, resiilting from seed from a 

 locality of high mean temperature, are 

 the first to show active growth in the 

 spring; while those resulting from seed 

 from a region of low mean temperature 

 will be last. A shorter growing season 

 is also characterized by a lower annual 

 increment as well as by density of form. 



APPLYING THE CONCLUSIONS. 



The practical application of these 

 facts is easy, and here is also found an 



explanation for some of the poor results 

 in forestry. For instance, it is said that 

 Scotch Pine {P. sylvestris) gives very 

 poor results in the United States and 

 that, therefore, it is not adapted to this 

 country. It is true that in Europe one 

 docs find poor stands of this species, yet, 

 on the other hand, there also occur very 

 fine stands. Other conditions being the 

 same, does it not seem reasonable to 

 place the blame upon the source of 

 seed ? 



In a region where the snow-fall is 

 heavy and the snow is of such a charac- 

 ter that it c ings to the branches and 

 leaves, producing heavy damage through 

 snow-break, the seedling resulting from 



