Dec. 189-1.] BOTANICAL SOCIETY OF EDINBUEGH. 337 



III. Stem - Eingixg Experiments on Broad - Leaved 

 (Dicotyledonous) Deciduous Trees. By A. D. 

 Eichardson. 



The experiments detailed here were made, at Professor 

 Balfour's sufrg-estion, in the winter of 1893-94, in order 

 to ascertain what effects would be produced on broad- 

 leaved trees possessing a heart-wood (duramen), as compared 

 with those possessing no heart- wood, by the removal from 

 their stems of a cylinder of bark along with a certain 

 amount of the underlying wood. At the same time the 

 familiar operation of ringing the bark was performed for 

 purposes of comparison. 



For the experiments ten trees, consisting of five kinds, 

 viz., two maples, two beeches, two horse-chestnuts, two 

 laburnums, and two oaks (common and Turkey) were 

 selected. From one tree of each kind there was removed 

 a cylinder of bark (rind) and wood about six inches long, 

 and from the other a cylinder of bark of the same length. 

 The thickness of the cylinder of bark and wood varied 

 with the kind of tree. In the maple, beech, and horse- 

 chestnut its cross-sectional area amounted to one-half that 

 of the whole stem (including bark) at the part operated 

 upon ; but in the oak and laburnum it consisted of the 

 bark and underlying sapwood (alburnum) only, which in 

 the oak amounted to two-thirds, and in the laburnum to 

 one-third of the cross-sectional area of the stem. 



Briefly, the results which followed these experiments 

 were : — 



In no case, as was to be expected, was any perceptible 

 effect upon leafage produced by the removal of bark only ; 

 nor was any perceptible effect produced by the removal of 

 both bark and wood in the case of those kinds which form 

 no true heart-wood, viz., maple, beech, and horse-chestnut. 

 Foliation and defoliation took place in these cases quite 

 normally, and the density of the foliage did not seem in 

 any instance to be less than usual. The oak and laburnum 

 from which both bark and wood were removed fared 

 differently. The oak was killed above the part operated 



TRANS. BOX. SOC. EDIN. VOL. XX. Y 



