BRITISH FOREST TREES 267 



it becomes thick and hard ; but in the power of healing such 

 wounds the elm surpasses even the ash. As a tree of the 

 forest, growing in admixture with other species, it stands next 

 to maple and sycamore in immunity from the ravages of in- 

 jurious insects. It is practically almost exempt from danger 

 on a large scale, although both active forms of Hyleshnts 

 rittatus and Scolytus destructor often do considerable damage 

 to the bark and sapwood of trees growing in the open, more 

 especially in and around large, smoky towns. Among cater- 

 pillars, those of Vanessa polychloros and Porthesia auriflita 

 do most injury to the foliage, whilst the greatest damage 

 inflicted on the mature wood is caused by the larvae of 

 Ptilinus pectinicornis and the caterpillars of Ztuzera (csatli. 



Elms are exposed to the same fungoid diseases as maple 

 and sycamore, arising principally from Nectria ditissima, N. 

 cinnabarina, and Phytophthora omnivora. 



Sylvicultural Treatment of Elms. Nowhere in northern 

 Europe do'elms occur forming pure forests, or as the principal 

 species in mixed woods, and there are very many localities, 

 well suited to its growth, where it is not even to be found 

 among the subordinate species, despite its vigorous growth, 

 the fine dimensions attainable on good soil, and the beauty 

 of its wood for cabinetmaking and furniture. Its neglect 

 sylviculturally and there is every reason to believe that 

 it was formerly to be found in our woodlands to a greater 

 extent than is now the case, is doubtless entirely due to 

 the large extent to which it is to be found throughout the 

 greater part of Britain along roads, as standards in hedge- 

 rows, in avenues, parks, &c., whence the supply of timber is 

 enough to cover the present demand for this particular kind 

 of wood. Throughout Holland, Belgium, and northern 

 France, it is to be seen adorning the towns and villages, as 

 well as along the main highways, to a much greater extent 

 than in Britain. In England it is a favourite tree for 



