82 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



9. The Blueing of Coniferous Timber. 



By Malcolm Wilson, D.Sc, F.R.S.E., Lecturer in Mycology 

 in the University of Edinburgh. 



Although the "blueing" of timber is well known both to 

 foresters and timber merchants no account of its distribution, 

 or of the fungi which cause it, has yet been ])ublished in this 

 country. In the books dealing with the diseases of trees and 

 timber the " blueing," if mentioned at all, is usually dismissed 

 very shortly with the statement that it is due to Ceratostomella 

 pilifera, Fries., an ascomycetous fungus. This disease of timber 

 has been known for some time both in the United States and 

 in Germany, and accounts of the causal fungi and their effects 

 on the wood have appeared in both these countries. 



There is a serious decrease in value of timber brought 

 about by "blueing." In this country "blued" wood is priced 

 considerably lower than healthy timber, and "blued" samples 

 are rejected when the timber is required for special purposes ; 

 *' blued" pit-props show a considerable depreciation in value. 

 In the United States blue-stained boards are graded lower than 

 the unstained, and since much of the staining develops in 

 otherwise high-grade material the financial loss is serious. 

 In Germany timber when "blued" diminishes considerably in 

 value, and is accepted unwillingly for such purposes as house- 

 building, ship-building, for sleepers, and even for firewood. Its 

 value for furniture construction is especially diminished, for the 

 dark-coloured streaks are particularly obvious when it is used 

 for that purpose ; generally speaking, infected timber diminishes 

 25-50 per cent, in value. It has been estimated that in Sweden 

 the depreciation in value of infected timber is 14 per cent., and 

 according to the regulations for the export of timber from the 

 country "blued" material must not be included amongst first- 

 grade samples. In Russia, where transportation is long 

 and difficult, the timber often lies for some time in the forest 

 before removal, and consequently the damage caused by 

 " blueing " is very serious. 



In view of the wide distribution of the disease in Britain, and 

 the considerable quantity of infected timber now coming into 

 the market, it is proposed in the present note to give an 

 account of the investigations already carried out on this 



