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The Museum Gazette 



bark of the top of the tree is quite smooth, the flutings ceasing 

 abruptly about 6 feet from the top. 



No. 3 is a very large tree and stands in an exposed situation. 

 It is quite dead and the lower part of its bole is denuded 

 of bark and left perfectly clean and smooth. There is not a 

 trace of an insect burrow or the like to imply that the bark 

 had remained after the tree's death. On the upper parts 

 of the tree the bark still adheres. 



The explanation of the conditions in these three trees is 

 the same for all. It seems probable that all have served as 

 lightning conductors. We know that the effect of lightning 

 current passing down the trunk of a tree is to generate steam 

 between the bark and the wood by heating the moisture in 

 the cambium layer. The quantity of this moisture will vary 

 much at different seasons of the year and somewhat in dif- 

 ferent trees. If, as in spring, the quantity be large the explo- 

 sion may completely strip the bark or at any rate loosen it all 

 round. If, on the other hand, the moisture be scanty then the 

 bark may be broken through at various places and the force 

 (i.e. steam) being thus liberated the detachment will be only 

 local. This is what may be supposed to have occurred in 

 tree No. i, whilst in No. 3 the bark was blown completely 

 off. The fluting in tree No. 2 was probably caused by 

 partial detachment which simply lifted the bark without 

 tearing, and then left it possible for the cambium to accumu- 

 late in the furrows, and subsequently to organise in ridges. 



It is desirable to observe the effects of lightning on different 

 species of trees. In the case of oaks, ashes, or beech-trees, 

 the course of the fluid being interrupted by large branches, 

 shattering often occurs. The straight stem of the fir, on the 

 other hand, allows the current to pass in direct lines to the 

 ground. We shall be much interested to know whether any 

 of our readers who have access to fir-woods can find examples 

 of what we may call "fluted trunks" or other evidence of 

 damage, and further whether any more plausible explanation 

 of the conditions described can be given than those which we 

 have ventured. 



