2l6 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



being able to germinate and establish themselves, that invasion 

 of these localities has been repeatedly attempted without success, 

 then I am sure their super-optimism would give way to some- 

 thing more practical. Further, if we study nature's progressive 

 movements we ought to be able to indicate the species most 

 suitable at any given stage, and by complying with the laws of 

 succession, assist this progressive march in the enrichment of 

 the soil with the object of utilising the latter in the development 

 of our woods. Retrogression in some cases, however, replaces 

 the onward movement, and a recognition of the occurrence of 

 this phase enables us to adapt our methods to check further 

 degeneration and, if possible, convert a retrograde movement 

 into a progressive one. 



" Multifarious and bewildering as the variety of its life-phases 

 is, the forest and the changes constantly going on in it are not 

 the disorderly results of accident. In their astonishing com- 

 plexity they are yet dependent on a few simple laws of nature. 

 To the degree in which we understand these, and their workings 

 to that degree, we will be able to control their results. To 

 understand clearly how much control is possible, we must bear 

 in mind that it is done not by suspending or reversing the actions 

 of the processes of nature, but by guiding and giving special 

 directions to them." 



