28 TREE-PLANTING. 



Canada and Virginia, it grows to the height of seventy 

 or eighty feet, and in good soil considerably exceeds 

 this measurement. On rich moist land it becomes a 

 large tree in a few years, and is readily distinguished 

 from the Lombardy poplar, by its leaves being 

 broader, and its young shoots being serrated, parti- 

 cularly towards the extremities, and is also of a much 

 darker colour. Its habit is also much more spreading, 

 its side shoots taking a wider and more horizontal 

 range, which often tempts pruning, which is not a very 

 safe experiment with poplars, as it often induces decay. 

 The Gray Poplar (P. canescens) is a native of 

 Britain, which grows rapidly, and is a large spreading 

 tree. In April it becomes conspicuous from the pro- 

 fusion of large catkins it throws out, which are two 

 or three inches in length. It thrives best in moist 

 soils, and is somewhat remarkable at an early age for 

 throwing out strong lateral shoots nearly equal in 

 length to the main shoot. When cut down young, it 

 .shoots freely, but at a later period of its growth, it 

 -springs more vigorously from the roots, and is con- 

 sequently objectionable in some situations, as it fills 

 the land with suckers. It is most readily propagated 

 by layers, and after being one year transplanted, the 

 plants are often six feet high, and fit for being finally 

 planted out, in the situations in which they are 

 intended to stand. It is considered a good tree to 

 plant with oak and silver-fir, to act as nurse, as it 

 furnishes a shelter which is adapted to the early 

 growth of these trees, and as it becomes of a useful 

 size in a few years, it can then be taken away, and its 

 timber made use of, when the other trees are 

 -established. 



