viii.] PLANTS AND ANIMALS. 129 



immigration of six new species of birds which feed 

 upon insects. At Farnham we are shown the reason 

 why the Scotch Fir, a thoroughly indigenous tree, 

 cannot grow unless protected by enclosure. 



Speaking of the Scotch Fir reminds us of another 

 change effected by man, by the introduction of foreign 

 species. The Scotch Fir (Finns sylvestris) is the only 

 truly native species of Pine or Fir in Britain, and is 

 held to be one of the most valuable of the European 

 Coniferse as a timber tree, producing, as it does, the 

 best " deal." But it is a slow-growing tree, and con- 

 sequently the timber-growers of this country have to 

 a large extent supplanted it by the introduction of 

 the Spruce Fir (Abies excelsd] and the Larch (Larix 

 enropcea), more rapid growers. Previous to the Gla- 

 cial Period the Spruce Fir was evidently a prosperous 

 native of this country, but in recent geological times 

 it was here unknown until its introduction three cen- 

 turies ago. To-day it is as common as the Scotch 

 Fir itself. The Larch is an even more recent impor- 

 tation, not having been introduced in any quantity 

 previous to one hundred and fifty years ago. Now 

 large areas are planted with it. So rapid is its growth 

 that Wordsworth called a plantation of it at Grasmere 

 " the vegetable manufactory." Now there is a vast 

 difference in appearance between the Scotch Fir 

 (which is really a Pine and not a Fir) and its sup- 

 planters the former being flat-headed, whilst the 

 latter, are conical and the introduction and exten- 

 sive cultivation of the latter must have effected a 

 considerable change in the landscape alone of 

 Scotland. But we know that such an important 



