530 TRANSACTIONS OF ROYAL SCOTTISH ARBORICITLTURAL SOCIETY. 



or to raise the measurement as soon as possible to that poikt if it 

 was necessary to begin lower in very young trees ; (3) to mark the 

 position with a circle of short lines of white paint, one being 

 specially marked as the starting-point ; (4) to use Chesterman's 

 steel tapes, graduated to centimetres by preference, specially made 

 with a square " ring," slightly wider than the tape, and included 

 in the graduation. Holding the bottom bar of the square with 

 the nail of the left forefinger against the measuring point, the tape 

 is passed round the stem, and the result read off where it passes 

 over the upright bar. T find it possible to measure smooth stems 

 thus to half a millimetre, and even roughish ones with a risk of 

 error of only from half to a whole millimetre. 



3. Eesults. — The annual observations chiefly show the rate of 

 girth-increase in different years of different species, the temporary 

 and permanent effects of extremely cold winters, the great reduc- 

 tion of increase caused by transplantation, for three or four years 

 in young trees and for six or seven in older ones, the occasional 

 total cessation of girth-increase for a year or more, with or without 

 eventual recovery ; the similar reduction as an effect of pruning, 

 and the disastrous effect of over-pruning. 



The monthly observations mainly show that the proportional 

 increase due to each month varies greatly with the species, that 

 some increase mostly in the first half, others mostly in the second 

 half of the growing season, and that some accomplish the bulk of 

 their annual increase in much shorter time than others. 



The short-interval observations, already published, show that the 

 Coniferse under observation started growing between 6th April and 

 3rd May, and ceased to increase between September 20th and 

 October 11th, and that the corresponding periods for the Decidua? 

 were from 20th April to 17th May, and from August 23rd to 

 September 27th; and that the rise and fall in the annual in- 

 crease was not progressive, particularly in the Coniferse, which 

 experienced a great retardation in midsummer, succeeding a 

 vigorous growth in spring, and preceding renewed vigour in 

 autumn, there being a complete cessation of increase for a week or 

 a fortnight in the genus Abies. 



The unpublished short-interval results are not yet put together, 

 but one interesting observation made this winter is that all of 

 thirteen Deciduous trees, measured for the purpose of ascertaining 

 the effects of hard frost on 30th January, were found to have con- 

 tracted on an average 2 millimetres, and had recovered their loss 

 after a thaw when remeasured on 4th February. D. C. 



