ON THE CAUSE OF RINGSHAKE IN TREES. 193 



which may enrich the discoverer, and cause his name to be 

 honoured not only by the present, but future generations. 



It is not necessary that I should definitely state in what 

 particular direction the student of arboriculture should direct his 

 chief attention, nor — as this is a wide field — can it be doubted 

 that much yet remains to be learned even by the wisest. What 

 arboriculturist does not find himself baffled in accurately ascer- 

 taining the cause of premature decay, or it may be of permanent 

 injury, produced upon some of his favourite specimens? Noxious 

 gases, putrid water, or other substances, such as fungoids, &c., 

 and insects ad infinitum, all have injurious effects upon plant 

 life. The arboriculturist's profession is an interesting one, leading 

 him to act not only for the supply and benefit of the present, 

 but for the future generation, and as a wise economist, interested 

 as he is in the selection, and gathering of seeds — sowing, culti- 

 vating, planting, and rearing of the same — the national require- 

 ments demand more than a transient consideration from him. 

 The crop he plants he scarce ever sees ready for cutting down 

 in his own brief day. But experience having taught him that 

 some kinds of trees produce a more remunerative crop than 

 others, supplying a most useful, and at all times a necessary 

 class of timber for national requirements, it behoves him care- 

 fully to ascertain on what variety of soil, on what exposures, 

 and at what altitudes he has generally seen them growing most 

 luxuriantly. He may have seen some handsome specimens of a 

 majority of the recent as well as the more remotely introduced 

 foreign plants. But his experience is calculated to lead him to 

 form a more correct idea of the suitableness of the various 

 soils which are best adapted for the growth of those species 

 indigenous or introduced into his locality. He may be ignorant 

 of scientific theories, but have a true practical experience, which, 

 in many cases, is far better than theory. And his ambition 

 ought to be to grow the most remunerative crop and greatest 

 possible bulk of sound useful timber in a given period of time ; 

 thus endeavouring to advance the knowledge of his profession, 

 along with others of his brethren, while studying to grow a 

 profitable crop for his employer, and that which will supply the 

 requirements of his country. The fact that unsound timber is 

 found in our forests is indisputable, and it is our object in this 

 paper to inquire as to the cause or causes of ringshake. I have 

 no hesitation in saying that any authors whose writings upon 

 this subject I have had the opportunity of reading do not 

 ascribe the condition to what I believe to be the true cause. Those 

 authors ascribe the cause of ringshake to the soil upon which 

 the tree grows. I would as soon believe that some noxious 

 gas floating in the air, or a shower of noxious vapour falling upon 

 it, could produce it, or that no African could be kept alive upon 



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