Pseudotsuga menziesii

Pseudotsuga menziesii (Mirb.) Franco – Douglas-fir

group: 	SOFTWOODS

Macroscopic structure of wood

heartwood/sapwood: 	heartwood

description: 	narrow to medium wide sapwood (3–6 cm), yellowish; heartwood reddish brown to reddish violet

rings: 	distinct boundary between rings; wide rings (narrow rings by wood from the North America); very abrupt transition from early wood to late wood in ring, high portion of late wood in ring

resin canals: 	slightly distinguishable, visible in X, R and T

rays: 	invisible (sometime visible in R)

texture: 	strikingly flatsawn (T) and radial figure (R); decorative wood

other: 	become darker in the air

Microscopic structure of wood

brief overview: 	RC; ray HetC, medium high; spiral thickenings

ring: 	very abrupt transition from early wood to late wood tracheids in ring	X

bordered pits on tracheids: 	usually one in a row (sometime paired)	R

tracheid thickenings: 	fine spiral	R, T

resin canals: 	small, predominantly solitary	X, T

epithelial cells: 	thick-walled epithelial cell, smaller (5–6)	X, T

rays: 	heterocellular	R

width of rays	uniseriate and fusiform	T, (X)

height of rays: 	medium high, 8–15 (25)	T

cross field pitting: 	taxodioid by early wood tracheids, piceoid by late wood tracheids (2–4–6)	R

ray tracheid: 	one or more rows along the upper and lower margins (sometime in the middle) of the ray, smooth-walled ray tracheid, sometimes spiral thickenings	R

axial parenchyma: 	absent or rare	X, (R, T)

other: 	thick-walled cells of rays

Wood properties

density: 	light

ρ 0: 	470 kg/m3

ρ 12-15: 	500 kg/m3

ρ green: 	700 kg/m3

shrinkage: 	medium

- volumetric (βV): 	13 %

- radial (βR): 	4,4 %

- tangential (βT): 	7,3 %

mechanical properties: 	related to the ring width

ultimate strength in compression ||: 	56 MPa

ultimate strength in bending: 	79 MPa

ultimate strength in tension ||: 	105 MPa

hardness: 	soft

Janka's hardness: 	43,5 MPa

technological properties: 	no problem with drying, working, finishing, uneasy chemical preservation; wood has the best technological properties with ring width 1–2 mm

resistance: 	rated as resistant to decay (heartwood)

Wood utilization

utilization as with Norway spruce and Scots pine; timber, particleboard, veneers, plywood, batten boards, inside and outside building constructions, boat building, mast and pole

References