Mar. 1903.] BOTANICAL SOCIETY OF EDINBURGH 411 



years its appearance in these respects would not alter. 

 The amount of foliage it would put forth each year would 

 increase, for the twigs would have ceased as a whole 

 from extending, and as they became effete towards their 

 extremities, younger and more numerous twigs would push 

 out somewhat lower down, and all would bear leaves. 

 Thus we see the constant increase in the amount of foliage 

 would be quite adequate to support an annual increment 

 such as the section displays for one hundred and fifty years 

 of its life. Then younger twigs would not so readily 

 push forth, consequently the leaves would become fewer, 

 and the annual increment, as shown by the section, would 

 become less ; and had not the tree been cut down this 

 process would have gone on — increasingly so — till the top 

 had become stag-headed and the bole of the tree hollow. 

 Asa Gray, in his statement of De Candolle's theory, says : 

 " The old and central part of the trunk of the tree may, 

 indeed, decay, but this is of little moment, so long as new 

 layers are regularly formed at the circumference. The tree 

 survives, and it is difficult to show that it is liable to death 

 from old age in any proper sense of the term." But to a 

 tree, the becoming hollow is of great moment. The trunk 

 is the only channel for the sap to pass from the roots to 

 the head, aud if the channel be narrowed by decay, less sap 

 will pass, and there will be fewer leaves as a consequence, 

 and the new layers formed at the circumference will become 

 thinner. This process only needs to go on a while and the 

 tree will no longer survive, and old age and its attendants 

 will as surely bring about the death of the tree as they do 

 that of other living organisms. 



Having refuted De Candolle's theory, and shown how 

 unreasonable Prof. Burnett's calculation is respecting the 

 age of the Cowthorpe Oak, we now take upon ourselves the 

 task of stating, not definitely, the age of the tree, but 

 particulars of its history, during the hundred years that it 

 has been known and recorded, with the hope that these 

 particulars may help us to form an estimate of the age — 

 within rather extended limits it is true, but probably as 

 near as it is possible. 



We have seen that in the life of a tree there is a period 

 when it grows in all directions, and another period when 



