Page 150 - Fundamentals of Air Pollution

118 8. Effects on Vegetation and Animals

TABLE 8-2
Composition of U.S. Forest-Type Groups by Foliar Terpene Emissions
Percent of Percent
total U.S. a pinene
forest area emitters Percent of isoprene emitters
Eastern type group
Softwood types
Loblolly-shortleaf pine 11 -100 Some from oak and sweetgum
associates
Longleaf-slash pine 5 -100 Some from oak and sweetgum
associates
Spruce-fir 4 -75 25% from spruce, which also emits a
pinene
White-red-jack pine _2 -90 10% from aspen trees
Subtotal 22% -91% -9%
Hardwood types
Oak-hickory 23 -10 70%, diluted by hickory, maple & black
walnut
Oak-gum cypress 7 -50 50% from plurality of oak, cottonwood
and willow
Oak-pine 5 -30 60%, diluted by black gum & hickory
associates
Maple-beech-birch 6 -15 Terpene foliates are hemlock and white
pine
Aspen-birch 5 -20 60%, diluted by birch, a pinene source
balsam fir and balsam poplar
Elm-a sh-cottonwood 4 30% from cottonwood, sycamore,
willow
Subtotal 50% -21% -45%
Total 72% — —
Western type groups
Softwoods
Douglas fir 7 -100
Ponderosa pine 7 -100 5% from aspen associates
Lodgepole pine 3 -90 10% from Engelmann spruce and aspen
Fir-spruce 3 -100 40% from spruce trees
Hemlock-Sitka spruce 2 -100 25% from Sitka spruce
White pine 1 -100 5% from Englemann spruce
Larch 1 -100
Redwood 0.5 -100
Subtotal 24.5% -98% ~2%
Hardwoods 2 —100% from aspen trees
Total 26.5%
Source: Rasmussen, R. A., /. Air Pollut. Contrl. Assoc. 22, 537-543 (1972).