198 ON THE CAUSE OF EINGSHAKE IN TREES. 



chiefly attributable to its badly formed top; but the ground 

 being of a spongy nature, would retain a large amount of 

 moisture. The tree was growing isolated from any evergreen 

 conifer, and frost would act powerfully on it, hence the action 

 of heavy winds on the tree, when frozen it may be to its very 

 centre during several stages of its growth, would produce the 

 effects now seen. As a general rule, I find those elms which are 

 what is often termed well-hearted trees worse than those which 

 have less redwood in them. Probably this may be attributable 

 to the fact that well-hearted trees are more rigid. I noticed this 

 particularly a few years ago when thinning out those elms 

 growing along the banks of the Blackburn; and this was apparent 

 too when 1 could discern no difference in the class of soil or 

 subsoil, or in the form of their tops, and if attributable to the 

 formation of the roots or their distribution, I do not understand 

 how it could be explained, seeing the majority of the well- 

 hearted trees were ringshaken, and none of the others. Why 

 not stop planting the former, and plant only the latter class ? 

 The former a-re the most valuable as well as the most useful, 

 therefore your proposition, if adopted, would cause a scarcity of 

 valuable elm. But this tree we have cut down is pumped in 

 the centre as well as ringshaken. The soil in this case has 

 nothing to do with that; it is the hard pan bottom. The 

 friction caused by the wind has injured some of its roots that 

 were resting on the hard pan, and produced decay in them, 

 which has been communicated by these wasting roots to the 

 stem. 



Try an oak now. Here is one at full maturity, with a 

 straight clean stem, and no heavy branches. Its ligneous 

 tissues do not seem spirally arranged. It is growing upon mossy 

 loam 14 inches deep, and resting upon a gravelly pan too. We 

 find it quite sound. Though growing upon the side of a knoll, 

 it is pretty well sheltered by Scotch and silver firs growing 

 round it. The ground is perfectly dry. Neither wind nor frost 

 has produced any deleterious effects here. 



Try this one on the margin of the plantation. One of its 

 heavy limbs is already broken. It is quite evident that thinning 

 has been long delayed on the margin, as this oak has very few 

 branches on either side. Save on the outside, the stem is inclined 

 outward, and the heaviest limb on the outside is broken off. 

 We find it growing on black loamy soil a foot deep, resting upon 

 a gravelly till subsoil. When cut down, it is seen to be ring- 

 shaken. What is the cause here ? Thinning has been too long 

 neglected, and this heavy limb now broken off, catching the 

 wind, has twisted the tree, so as to produce or cause these 

 various rents we now see. Would frost have no injurious 

 effects upon this tree ? I do not think so. Seeing a Scotch fir 



