Pyrus communis

Pyrus communis L. – Common pear

group: 	DIFFUSE-POROUS HARDWOODS

Macroscopic structure of wood

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

description: 	pinkisch to reddish brown colour

rings: 	small visible boundary between rings

vessels	only micro pores in wood (longitudinal sections smooth)

rays: 	invisible or small ray fleck, visible only in R

texture: 	regular, dense, light stripes (T); lustreless

other: 	very often occurrence of pith fleck (reddish brown to dark brown-black colour)

Microscopic structure of wood

brief overview: 	Ray 1–3 seriate, HomG; simple perforation plate, heartwood substances

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

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

type of vessel perforation: 	simple	R

vessel thickenings: 	sporadic occurrence of fine spiral	R, T

rays: 	homogeneous	R, T

width of rays	1–2–3	T, (P)

apotracheal parenchyma: 	numerous – marginal, diffuse	X

tracheids in basic tissue: 	very numerous – fibre tracheids	R, T

other: 	crystals in ray cells; heartwood substances in vessels and in rays; pith flecks

Wood properties

density: 	moderate heavy to heavy

ρ 0: 	700 kg/m3

ρ 12-15: 	750 kg/m3

ρ green: 	1000 kg/m3

shrinkage: 	medium

- volumetric (βV): 	14,1 %

- radial (βR): 	4,6 %

- tangential (βT): 	9,1 %

mechanical properties: 	strong, elastic

ultimate strength in compression ||: 	54 MPa

ultimate strength in bending: 	98 MPa

ultimate strength in tension ||: 	100 MPa

hardness: 	moderate hard to hard

Janka's hardness: 	79 MPa

technological properties: 	no problem with drying, working and finishing

resistance: 	rated as slightly or non-resistant to decay

Wood utilization

veneers, furniture, drawing instruments (set squares and curves), woodcarving, turning work, tool handles, picture frames, shafts of billiard cues; pear is used to imitation of ebony or some exotic woods

References