Betula pendula

'Betula pendula'' Roth. – Silver birch'''

group: 	DIFFUSE-POROUS HARDWOODS

Macroscopic structure of wood

heartwood/sapwood: 	sapwood (possible occurrence of false heartwood)

description: 	yellowish, greyish to greyish white colour

rings: 	small visible boundary between rings

vessels	only micro pores in wood (longitudinal sections smooth, sometime occurrence of very fine grooves), vessels make light points in transverse section

rays: 	small ray fleck, visible only in R

texture: 	slightly flatsawn (T) and slightly radial figure (R), burl (T); lusterless and decorative wood

other: 	very often occurence of pith flecks (yellowish brown colour); veneers with special figures are prefered

Microscopic structure of wood

brief overview: 	Ray 1–4 seriate, HomG; scalariform perforation plate

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

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

type of vessel perforation: 	scalariform	R

rays: 	homogeneous	R, T

width of rays	1–4	T, (X)

apotracheal parenchyma: 	slightly numerous – diffuse, marginal	X

tracheids in basic tissue: 	slightly numerous – vascular, vasicentric, fibre tracheids	R, T

other: 	often occurrence of pith flecks

Wood properties

density: 	moderate heavy

ρ 0: 	610 kg/m3

ρ 12-15: 	650 kg/m3

ρ green: 	850 kg/m3

shrinkage: 	medium

- volumetric (βV): 	13,7 %

- radial (βR): 	5,3 %

- tangential (βT): 	7,8 %

mechanical properties: 	strong, elastic and bendy

ultimate strength in compression ||: 	51 MPa

ultimate strength in bending: 	147 MPa

ultimate strength in tension ||: 	270 MPa

hardness: 	moderate hard

Janka's hardness: 	66 MPa

technological properties: 	no problem with working, bending and finishing

resistance: 	rated as slightly or nonresistant to decay

Wood utilization

veneers (valuable are veneers with bird's-eye figure; Karelian birch, masur birch and flame or ice birch are distinctively figured varieties), plywoods, furniture (chairs parts and upholstery frames), woodcarving, turning work (bobbins, spools, cotton reels), brushes, small tool handles, toys, wood haberdashery and imitation jewellery, chemical and pulp industry, fuel wood

References