The timbers of commerce 



Colour. Heart-wood brownish : brownish-yellow : rosy- 

 white. " Vinous red at length " (69). Fades gradually into 

 the yellowish, reddish, or white sap-wood. 



Anatomical Characters. Transverse section : — 



Pores. Scarcely visible, rather fine, size 4, gradually diminish- 

 ing to the Autumn zone : uniformly scattered in concentric, wavy- 

 straggling lines : very numerous, 150-250 per sq. mm. : single or 

 in radial groups of as many as 7 in the late Autumn wood. 



Rays. Just visible, very fine, size 6, uniform : equidistant, 

 about the width of a large pore apart, nearly straight, avoiding 

 the larger pores only : denser and of fighter colour than the 

 ground-tissue : very numerous, 10-13 P er mm - 



Rings. Very clear : boundary, a fine of contrast between the 

 dense, small-pored Autumn wood and the spongy, large-pored 

 Spring wood. Contour undulating here and there. 



Soft-tissue. Lines of single cells without order. 



Flecks. Usually very numerous, but not invariably present : 

 mostly brown and plano-convex in section, with a bluish centre, 

 1-2 mm. wide. 



Pith. Variable in size, usually 2-5 mm. wide : white : later 

 yellowish or brownish. 



Radial Section. Lighter in shade than the Transverse section. 

 Pores readily visible though extremely fine : generally empty and 

 shining. Rays just visible as minute marks of slightly darker 

 colour than the ground. Rings very faint, narrow, brownish 

 bands. Flecks narrow, brown lines to £ mm. wide. 



Tangential Section. As the radial, but the pores are not so 

 crowded. Rays invisible without microscope. In the rings, the 

 brown wood shows up much more prominently and the flecks 

 appear as broad, brown lines up to 2 mm. wide. 



Type specimens from commercial sources and from trees known 

 before felling, checked by Nordlinger's section. The structure, 

 apart from the physical characters and colour, is insufficient to 

 distinguish one species of Salix from another, or indeed from 

 Populus, Wiesner to the contrary notwithstanding. 



No. 207. BLACK POPLAR. Populus nigra. Linn. 



Plate XV. Fig. 130. 



Natural Order. Salicineae. 



Alternative Names. Peuplier franc : Leard : Liardier : Bouil- 

 lard in Central France (8). 



Sources of Supply. Europe. 



Physical Characters, etc. Recorded dry- weight 25-36 J lbs. per 

 cu. ft. Hardness Grade 8, compare White Pine or Lime-tree. 

 Smell or taste none. Burns very well : consumes rapidly : embers 



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