REPRODUCTIVE POWER. 67 



Another very important point is the size and nature of the 

 seed. Species which have a small, light and winged seed 

 reproduce themselves more easily and extensively, than those 

 with a heavy or wingless seed. Moreover, it so happens, that 

 the species with light or wdnged seeds, such as birch, aspen, 

 willow, Scotch pine, spruce, are comparatively less sensitive 

 in respect of the factors of the locality, than, for instance, 

 oak, beech, silver fir, maple, and sycamore, wdth their heavy 

 seeds. The consequence is, that the power of reproduction 

 peculiar to the first named species is much greater than that 

 of the last mentioned. Instances where oak and beech are 

 ousted by Scotch pine and spruce can be frequently seen, 

 while the latter, in their turn, have to struggle against the 

 inroads made on them ])y birch, aspen, and willow. 



b. Fk('productio)i from Siool .s/too/s and Roof suckers. 



This method of reproduction applies to coppice woods. It 

 occurs in two ways : — 



Either : On that part of the stem which remains, after a 

 tree has been cut down, dormant or adventitious buds 

 develop into shoots; they are called " stool shoots." 



Or : Buds are formed on the roots, which develop into 

 aerial shoots, such shoots being called " root suckers." 



In both cases the nourishment and growth of the new- 

 individual depend on the continued root activity of the mother 

 plant. If the new individual is capable of producing root 

 buds and of developing them into roots, it becomes inde- 

 pendent of the mother plant ; in such a case reproduction is 

 established by a division of the mother plant. 



Eeproduction in the manner just described is strongest 

 during youth, and the faculty is maintained, according to 

 species, for different periods of time. The better the condi- 

 tions of growth, the longer will the reproductive power be 

 maintained. A thin and young bark reproduces more freely, 

 than thick and old bark. Favourable places are the neck of 

 the root stalk and wounds. 



F 2 



