2l8 TRANSACTIONS OF ROYAL SCOTTISH AREORICULTURAL SOCIETY, 



22. Sections of Larch Timber, showing the Effects 

 of different Soils on the Growth.' 



By (lii.BKRr Brown, (iranlown-on-Spey. 



The specimens consisted of six blocks taken from different 

 larch trees, three of which showed decayed heartwood and 

 three sound timber. The first group were taken from trees 

 grown on ground with an upper layer of medium forest soil, 

 and an inferior under layer consisting either of " pan " or 

 poor gravel. It should not be assumed that all larches grown 

 on such soil suffer from rot, but it may be said that on 

 certain areas containing soil of this nature heart-rot is common. 

 It is a significant fact that on a more or less uneven plain, 

 with slight hollows where soil has collected and is therefore 

 fairly deep, the larches yield sound timber, while on the 

 adjoining heather ground they are more or less severely 

 attacked by rot. 



The second set of specimens included trees which have been 

 grown on soil of sufficient depth, and with a certain amount of 

 natural drainage. The composition of the soil varied; in some 

 places it was pure loam, in others this was mixed with broken 

 rock, insufficient in quantity to check the growth of the tree. 

 Such soils admit of a free circulation of air about the roots. 



The specimens were taken from trees of various ages, and 

 may be described as follows : — 



No. I. (Unsound). Taken from a tree about thirty-five years 

 of age, grown in a mixed crop of Scots fir and larch on a south- 

 west aspect, about 700 feet above sea-level. The upper layer 

 of soil is a black friable loam, the under layer is hard, rubbly 

 and pan-like, being compo.sed of rough gravel with a slight 

 covering of clay, and is of extremely poor quality. The larch 

 had flourished in the thin upper layer of good soil, but suffered 

 much when the roots suddenly came in contact with the pan. 

 The tap-root had quite decayed, and the rot had spread from 

 the root up into the stem. 



No. 2. (Unsound). This section was taken from a tree about 

 fifty-five years of age. South exposure, 800 feet altitude, grown 

 on a soil of damp, sterile nature, except a few inches on the 



' Extracted from an es.say .subiintled fur coiiipelilion. 



