1885.] METEOROLOGY. 305 



HOW LIGHTNING STRIKES TREES. 



IT may not be unprofitable to divert the lightning discussion, 

 which 'appears to claim space in every succeeding number of 

 this journal, to the manner in which the electric fluid afifects 

 arboreal destruction. According to Sir Eobert Christison, at least 

 three kinds of injury have been deserved from lightning. A trunk 

 is sometimes blown into shivers, and the whole leafy superstructure 

 brought down in a moment by the entrance of the electric fluid. 

 At other times the same agency rips the bark in one or more lines 

 from the point of impact down to the ground, occasionally tearing 

 off a narrow strip of bark, and amputating also any branch it 

 encounters in its descent, or so damaging the tissues connecting 

 the branch with the trunk, that the latter dies. Sometimes it 

 seems to sweep around between the wood and the bark, throwing 

 off the bark in great sheets round and round the whole girth of 

 the tree. It is also often said to amputate branches without other 

 damage. But such simple injuries may be rather traced to the 

 furious temporary hurricane often the concomitant of a thunderstorm. 



In the paper in the 12th volume of the Transactions of the 

 Edinhurgli Botanical Socicttj, from which we quote, note is made of 

 the destruction of a magnificent wide-spreading oak at Edmon- 

 stone House, eight miles from Edinburgh, in 1848. Some of a 

 bridal party, looking out upon the lawn, saw this noble tree, 11 

 feet in girth of trunk, struck by a flash, and instantly sink on the 

 ground, leaving only a portion of the central part of the trunk 

 standing upright like a perpendicular pile of white planks. Two 

 days afterwards the great limbs lay around the riven trunk in their 

 original arrangement, pinning to the ground with their massive 

 elbows, white planks from the trunk, 4 to 10 feet long, 6 or 8 

 inches wide, some of them looking as if they had come from the 

 carpenter's shop. Several similar planks lay outside the wreck 

 altogether, in one direction, at a distance of 108 feet from the trunk. 



Sometimes the damage done by the second process is confined 

 to bark-stripping, or the destruction of a branch, not otherwise 

 injuring the life of the tree. And this appears to be the commonest 

 consequence of a lightning stroke. A long ribbon of bark, 10 feet 

 at least in length, carrying away with it some adhering layers of 

 wood, has been thus ripped off; but farther down the trunk, fresh 

 branches have subsequently developed. 



In an instance of the third process of destruction, the lightning 

 struck an ash tree about 2.5 feet from the ground, close to the 

 second and principal branching of the trunk. It had there torn 

 down a small branch, the seat of which was marked by a scar in 



u 



