TWO DISEASES OF SPRUCE UNDER INVESTIGATION IN GREAT BRITAIN

Descriptions are given of two apparently distinct diseases. One, termed 'group dying', occurs mostly in Sitka spruce {Picea sitcbensis Carr.) but sometimes in Norway spruce (P. abies Karst.), and is characterized by progressive death of the roots and a tendency for the trees to die in small groups in the stand. Trees between 20 and 30 years of age are usually attacked. The second disease is termed 'top dying ' and is confined to Norway spruce. There is a gradual loss of needles commencing usually in the upper crown and a reduction in height increments over a number of years. The roots and stem are the last portions of the tree to die. The symptoms are very similar to those of drought, but drought as a complete explanation is unsatisfactory. ' I 'WO diseases of spruce which have attracted notice for a number of years in J- Great Britain are being investigated at the Research Station of the Forestry Commission. Except that both can be fatal, they have little in common and indeed on some points are directly antithetic. Since in neither case has the cause been definitely ascertained, they have till now been termed, respectively, 'group dying' and 'top dying ' of spruce. GROUP DYIN