C 156 3 
X. Upon the different qualities of the alburnum of spring and 
winter-felled oak trees . By Thomas Andrew Knight, Esq. 
F. R. S. 
Read April 20, 1820. 
The timber of oak trees, felled in winter, was formerly very 
generally believed to be much superior in quality to that 
afforded by similar trees felled in spring ; and the same 
opinion appears to be still rather extensively entertained ; 
though the practice of felling in winter has wholly ceased, on 
account of the encreased value of the bark. But efforts have 
been made, and supposed to have been successful, to obtain 
the advantages of both seasons of felling, by taking off the 
bark in spring, and suffering the tree to stand till the ensuing 
winter. A good many facts, which had come within my own 
observation, and information which I received from other 
sources, had satisfied me that the durability of the alburnum, 
at least, of oak trees is considerably increased by this mode 
of management ; and I was, consequently, led to make 
a few experiments ( with the result of which I now take the 
liberty to trouble the Royal Society ) with the hope of dis- 
covering the cause of this supposed superiority in the quality 
of the wood of winter-felled trees. 
In the spring of 1817, two oak trees, of nearly the same 
age, and growing contiguously in the same soil, were selected, 
each being somewhat less than a century old. The one was 
deprived of its bark, to as great an extent as the inexperience 
