Populus nigra

Populus nigra L. – Black poplar

group: 	DIFFUSE-POROUS HARDWOODS

Macroscopic structure of wood

heartwood/sapwood: 	heartwood

description: 	wide sapwood, white to pinkisch brown; heartwood light brown, greyish brown, olive brown to dark brown; feltlike surface in longitudinal sections

rings: 	less visible boundary between rings, very often wide rings

vessels:	only micro pores in wood (longitudinal sections smooth, sometime occurrence of very fine grooves)

rays: 	invisible

texture: 	indistinct flatsawn (T) and indistinct radial figure (R), wavy grain (R) and burl (T); little decorative wood

other: 	occurrence of pith fleck

Microscopic structure of wood

brief overview: 	Ray 1 seriate, HomG; simple perforation plate

ring: 	invisible boundary between early and late wood within ring	X

vessel types and arrangements: 	only microvessels; microvessels solitary or in radial multiples (up to 4)	X

type of vessel perforation: 	simple	R

rays: 	homogeneous	R, T

width of rays	1	T, (X)

apotracheal parenchyma: 	slightly numerous – marginal	X

other: 	thin-walled libriform fibres; pith fleck

Wood properties

density: 	light

ρ 0: 	390 kg/m3

ρ 12-15: 	420 kg/m3

ρ green: 	730 kg/m3

shrinkage: 	medium

- volumetric (βV): 	12,8 %

- radial (βR): 	4 %

- tangential (βT): 	8,5 %

mechanical properties: 	weak and brittle

ultimate strength in compression ||: 	35 MPa

ultimate strength in bending: 	60 MPa

ultimate strength in tension ||: 	77 MPa

hardness: 	soft

Janka's hardness: 	27 MPa

technological properties: 	no problem with drying, uneasy working

resistance: 	rated as slightly or non-resistant to decay

Wood utilization

veneers industry, plywoods, battenboards, matches, crates, boxes, wood wool, cheap burial caskets, fuel wood and pulp industry

References