162 FORESTS, WOODS, AND TREES 



shallow soils, and is remarkably resistant to wind. It is, 

 however, slow in growth under these circumstances, pro- 

 ducing a remarkably tough wood. Cornish elm is suitable 

 for planting in shelter belts near the sea, and may be 

 introduced into broad-leaved woods in Wales, Ireland, and 

 the west of Scotland. 



5. Dutch elm {Ulmus major). The origin of this tree is 

 obscure. It is now widely spread in hedgerows in England 

 from Cornwall to Yorkshire. It produces suckers freely, 

 but the seed is absolutely unfertile. This elm grows fairly 

 well in clay soil, and produces a soft wood, which is readily 

 worked by the carpenter, and is used for purposes where 

 strength is not required. 



6. Huntingdon elm {Ulmus vegeta). This elm is of 

 hybrid origin, and is remarkably fast in growth. So far as 

 I know, it has never been planted as a woodland tree ; but 

 it deserves a trial in plantations at low elevations, where, 

 mixed with beech in small groups, it would probably 

 develop a tall, straight, clean stem. Planted in the open, it 

 tends to be wide-spreading in habit. 



Birch. — The birch, being a light-demanding tree with 

 very sparse foliage, does not improve the soil to any con- 

 siderable degree ; and its production of timber per acre is 

 meagre. Nevertheless its use in forestry is not un- 

 important, as it is our hardiest tree, capable of growing in 

 the poorest soils, and reproducing itself with the greatest 

 ease. Natural woods of birch occur at higher elevation 

 than those of any other species, ascending in some Highland 

 glens to 2000 feet. In the Pennines, birch forms woods 

 up to 1250 feet, and scrub as high as 1500 feet elevation. 

 The ground vegetation in such wood or scrub differs little 

 from that of the adjoining hill pasture or moorland ; and 

 may consist of wiry grasses, heather, and bilberry, or be 

 wet moor with peat plants. Birch thus occupies parts of 

 the hill pasture and heather moor zones ; and would doubt- 

 less spread over much more extensive areas, but that it is 

 kept down by grazing, as sheep destroy the seedling trees. 



