74 



BRITISH FOREST TREES. 



difference in strength of constitution of the indivi- 

 duals. Closeness of rearing and consequent tall 

 nakedness of stem, and disproportion of leaves to 

 stem, would alone induce this in a few years longer 

 even in good soil, excepting perhaps in protected 

 narrow dells ; but the decay commences much sooner 

 when the soil is unfavom-able, and is no doubt accele- 

 rated by the mode of extracting the seeds by kiln- 

 drying the cones, and by using a weak variety of the 

 plant. The approach of this decay may often be no- 

 ticed, several years previous, in the saw-cross section 

 of the stem mid -way up the tree — an irregular por- 

 tion of the section appearing of a different shade, 

 from breaking off free and irregular before the teeth 

 of the saw, and not having so much fibrous cover as 

 the healthy part. When Scots fir rises natm-ally, 

 it is not nearly so subject to this decay even in very 

 inferior soils : the plants having generally much more 

 room from the first, do not rise so tall, have more 

 branch in proportion to stem, thence are more vi- 

 gorous. The cones not being injured by kiln-dry^ 

 ing, may also account for this. 



The fact that the red pine in Scotland has fewer 

 sap-wood layers than the red pine of Memel or of 

 North America, and also the fact that, in most si- 

 tuations in Scotland, the red pine soon decays — soon- 



