Aspen (the genus Populus) is composed of 35 species which contain the cottonwoods and poplars. Species in this group are native to Eurasia/north Africa [25], Central America [2] and North America [8]. All species look alike microscopically. The word populus is the classical Latin name for the poplar tree.
Other Common Names
Populus grandidentata American aspen, aspen, bigtooth aspen, Canadian poplar, large poplar, largetooth aspen, large-toothed poplar, poplar, white poplar
Populus tremuloides American aspen, American poplar, aspen, aspen poplar, golden aspen, golden trembling aspen, leaf aspen, mountain aspen, poplar, popple, quaking asp, quaking aspen, quiver-leaf, trembling aspen, trembling poplar, Vancouver aspen, white poplar
Distribution: Quaking aspen ranges from Alaska through Canada and into the northeastern and western United States. In North America, it occurs as far south as central Mexico at elevations where moisture is adequate and summers are sufficiently cool. The more restricted range of bigtooth aspen includes southern Canada and the northern United States, from the Atlantic coast west to the prairie.
The Tree: Aspens can reproduce sexually, yielding seeds, or asexually, producing suckers (clones) from their root system. In some cases, a stand could then be composed of only one individual, genetically, and could be many years old and cover 100 acres (40 hectares) or more. Most aspen stands are a mosaic of several clones.
Aspen can reach heights of 120 ft (48 m), with a diameter of 4 ft (1.6 m). Aspen trunks can be quite cylindrical, with little taper and few limbs for most of their length. They also can be very crooked or contorted, due to genetic variability. The bark of the two species can be quite variable in color and degree of furrowing. The leaves of aspen can vary from nearly round to ovate, with small to large teeth. Aspen trees are dioecious, that is, they occur as either male or female trees.
General Wood Characteristics: The sapwood of aspen is white, blending into the light brown heartwood. The wood of aspen has a uniform texture; is straight grained, light and soft; and has good dimensional stability and low to moderate shrinkage.
Weight
Weightb
Species MC SGa lb/ft3 kg/m3
Populus Green 0.36 43 689
grandidentata 12% 0.39 27 433
(bigtooth Ovendry 0.41 NA NA
aspen)
Populus Green 0.35 43 689
tremuloides
(quaking 12% 0.38 26 417
aspen)
Ovendry 0.40 NA NA
aReferences: specific gravity, green and
12%, (98);
specific gravity, ovendry, (59).
bReference (59).
Mechanical propertiesa
Property Green Dry
Populus grandidentata (bigtooth aspen)b
MOE 1.12 106 7.722 GPa 1.43 106 9.860 GPa
lbf/in2 lbf/in2
MOR 5.40 103 37.233 MPa 9.10 103 62.745 MPa
lbf/in2 lbf/in2
C| | 2.50 103 17.238 MPa 5.30 103 36.544 MPa
lbf/in2 lbf/in2
C 0.21 103 1.448 MPa 0.45 103 3.103 MPa
lbf/in2 lbf/in2
WML 5.70 39.302 7.70 53.092
in-lbf/in3 kJ/m3 in-lbf/in3 kJ/m3
370 lbf 1645.76 N 420 lbf 1868.16 N
Hardness
Shear| 0.73 103 5.033 MPa 1.08 103 7.446 MPa
| lbf/in2 lbf/in2
Populus tremuloides (quaking aspen)c
MOE 0.86 106 5.929 GPa 1.18 106 8.136 GPa
lbf/in2 lbf/in2
MOR 5.10 103 35.165 MPa 8.40 103 57.918 MPa
lbf/in2 lbf/in2
C| | 2.14 103 14.755 MPa 4.25 103 29.304 MPa
lbf/in2 lbf/in2
C 0.18 103 1.241 MPa 0.37 103 2.551 MPa
lbf/in2 lbf/in2
WML 6.40 44.128 7.60 52.402
in-lbf/in3 kJ/m3 in-lbf/in3 kJ/m3
300 lbf 1334.40 N 350 lbf 1556.80 N
Hardness
Shear| 0.66 103 4.551 MPa 0.85 103 5.861 MPa
| lbf/in2 lbf/in2
aRelatively low strength, moderate stiffness and shock
resistance.
bReference (98) except for hardness (59).
cReference (98).
Drying and shrinkagea,b
Percentage of shrinkage
(green to final moisture
content)
Type of shrinkage 0% MC 6% MC 20% MC
Tangential
Populus grandidentata 7.9 6.3 2.6
(bigtooth aspen)
Populus tremuloides 6.7 5.4 2.2
(quaking aspen)
Radial
Populus grandidentata 3.3 2.6 1.1
(bigtooth aspen)
Populus tremuloides 3.5 2.8 1.2
(quaking aspen)
Volumetric
Populus grandidentata 11.8 9.4 3.9
(bigtooth aspen)
Populus tremuloides 11.5 9.2 3.8
(quaking aspen)
aWater soaked material can develop “wetwood” from
bacteria, causing a collapse in the zone between
sapwood and heartwood during drying.
bReferences: 0% MC, (98); 6% and 20% MC (90).
Kiln drying schedulea
4/4, 5/4, 8/4 10/4 12/4 16/4
Condition 6/4 stock stock stock stock stock
Normal wood T12-E7 T10-E6 T8-E5 T8-E5 T7-C4
Wet streak Table 109 Table NA NA NA
or 110
collapse
prone
aReferences (6, 86).
Working Properties: Aspen does not split when nailed, machines easily with a slightly fuzzy surface, and turns, bores and sands well. It holds nails poorly to fairly well, but glues, prints, and holds paint well. It is easily pulped by all commercial processes.
Durability: Rated as slightly or nonresistant to heartwood decay.
Preservation: Extremely resistant.
Uses: Pulp for books, newsprint and fine printing papers. Fiberboard, wafer board, sheathing, decking, decorative applications, boxes, crates, pallets, furniture parts, lumber core, veneer, match sticks, tongue depressors, paneling, excelsior.
Toxicity: Sawdust may cause dermatitis (40, 64, 105).
Additional Reading: 29, 55, 68, 70, 74. 55, 66, 68, 74, 79. 28, 29, 42, 43, 44, 48, 50, 55, 56, 68, 72, 73, 74, 79, 92, 97, 102. 74, 75, 77, 99, 106. 101.