Periodical Literature 505 



low areas, but mthin the protection forest the intruder spruce 

 needs a great deal of attention, because the spruce is the timberline 

 tree of the future. 



The upper line of tree growth has a tendency to recede. It 

 retreats down the mountain from one century to another. Timber- 

 line has previously been higher, which we deduce from the rem- 

 nants of pine trees dug up from former lakes and ponds within 

 the barrens above the present upper limits of tree growth, and over 

 the denuded alpine regions. 



The pine is on the decrease, not only at lower elevations where 

 it is being suppressed by the spruce and where it previously reigned 

 supreme, but also on the slopes, and we must face this truth. How 

 much of this can be laid to the spruce ? We know that spruce is a 

 comparatively late immigrant in this covmtry (Norway). Slowly 

 but surely, under cover, it has penetrated deep passes and valleys, 

 always behind and under some other species, so that now in the 

 east and south it is on a par with the original stands of pine. It has 

 won out in Trondelagen, further north and throughout Helgeland. 

 It is the same in the lowlands, up the principal water courses, both 

 on sunny and shaded slopes, except that progressing up the vaUey 

 spruce lags behind on sunny slopes, while in the shade its advance 

 takes place more rapidly. 



Differently in different watersheds, and above these temporary 

 limits the pine reigns still, and above the pine is the birch. The 

 situation, therefore, is this: spruce crowds the pine from below and 

 birch crowds it from above, and between these we find mixtures 

 and transitions in all kinds of variation in ascending order. Below 

 are the unbroken spruce columns, ahead and further up the ragged 

 pine and spruce formations, on the field of battle; still farther 

 ahead and up the stronger individuals in hand to hand conflicts 

 with a host of the enemy. 



The pine will continue to decrease in area with a corresponding 

 increase in the spruce type, and spruce will replace pine in the 

 upper belts as well as in the valleys and on the general slopes. 

 There is at present no sign that the reduction of the pine type will 

 be halted, and spruce has already gained the summits and upper 

 limits in several places on the shaded slopes farther south. 



The White birch gives help to the advance of the spruce. The 

 conifers go higher when protected by birch, stand denser and bear 

 seed at higher elevations. But where it is missing, which happens 



