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CHAPTER IV. 



STAG-HEADEDNESS. 



1. Description and Causes. 



It has been already stated that red rot frequently attacks 

 very old trees, rendering their stems hollow, but another sign 

 of excessive old age is the death of some of the topmost 

 branches of a tree, which has no longer sufficient vigour to 

 pump water so far. The death of these branches causes them 

 eventually to break off, and atmospheric moisture is then 

 admitted into the trunk, and rot commences and penetrates 

 downwards towards the roots. Stag-headedness may, how- 

 ever, occur in immature trees, and is then due to one of the 

 following causes : — 



(a) When trees which have been growing in a dense wood 

 are suddenly exposed as standards, as in natural regeneration 

 in high forest, or after the felling of the underwood in 

 coppice-with-standards, the surface moisture of the soil may 

 be reduced and the trees consequently become stag-headed. 

 In some cases such trees, and especially oaks, having com- 

 paratively soft bark, owing to their formerly protected state 

 in a dense wood, j)ut out numerous epicormic branches from 

 the dormant buds along their stems, which absorb the sap 

 that would otherwise reach their crowns. This tends to cause 

 stag-headedness, which may, however, be obviated by one or 

 two prunings of the epicormic branches, until the bark 

 becomes too hard for them to form. 



{h) In forests of lightdemanders such as oak, larch, ash, 

 Scots j)ine, the soil may be completely sheltered by the crop 

 up to a certain age, but after 40 — 60 years the leaf- canopy 

 ceases to be sufficiently close to protect the soil from the sun, 

 which gradually dries it up, and thus causes stag-headedness 

 in the trees, unless the soil be protected by an underwood of 

 shadebearers. This result follows more rapidly on hot 



