54 Characteristics of Common Forest Trees 



at greater elevations. The former should always be specified when 

 an order is given for seeds or plants. 



This species was introduced into this country about one 

 hundred years ago. It is eminently suited for pure woods; the height- 

 growth is possibly as rapid as any conifer grown in this country, 

 under suitable conditions. The shade-bearing capacity of this tree 

 is probably under-estimated ; and the timber, to be clean, must be 

 grown under a dense canopy. If planted with other species, the 

 timber is apt to be rough and to possess large knots, as most of our 

 shade-bearing trees are not suitable for the soil required by the 

 Douglas fir, and are overgrown on the soils suited for this species. 

 This has led to an under-estimation of the quality of the timber. 

 Moreover, during the time that the timber now on the market was 

 planted, the seed of the Douglas fir was expensive ; hence the rarity 

 of pure woods of it. 



The timber properly grown is probably of 20 per cent, more 

 value than Scotch pine, on an average. This species has the power 

 of producing a new leader when this is lost — unusual in conifers. 



The soil suitable for this species must be capable of free natural 

 drainage, and in this class of land — provided that the subsoil is not 

 chalk — good timber, abundantly produced, is procured. 



Nursery treatment. This resembles that of the spruce. Frost 

 protection may be required in the nursery. 



4. Common or Norway Spruce {Pkea excelsa). 



Distribution. This species is not indigenous. The centre of 

 its distribution is Central Europe. According to Brown, it was 

 introduced into this country in 1548. 



It is a tree naturally growing on the lower mountains, but it 

 descends to the lowlands on the shores of the Baltic. According to 

 Schlich, it is found in the Alps at an elevation of 6,000 feet. 



Soil. The root-system of this species is shallow ; con- 

 sequently, it is liable to be blown down by wind, sometimes to 

 a considerable extent. It is much damaged by drought. 



