b. Aerial photo (28 August 1998) showing general locations of ordnance
firing events where samples were collected.
Figure 1 (cont'd).
included the Washington Range as riverine gravelly
floodplains of the Delta River probably requires a much
barrens with species such as Oxytropis campestris,
longer time for the development of forests (balsam
Dryas durommondii, Potentilla multifica, Shepherdia
poplar and white spruce), and at some stage grassy
canadensis, Eleagnus commutata, Potentilla fruticosa,
meadows appear to develop in places that are important
Fragaria virginiana, Populus balsamifera, and
grazing areas. Also, several legumes (Hedysarum,
Astragalus, Oxytropis, Avena, Dryas drumondii, and D.
Much of the terrace of the Washington Range, where
octopetala) play a role in succession and willow is less
we sampled for explosives, is bare gravel with localized
important here than along the Tanana. Particularly
areas of sparse shrubs mostly consisting of silverberry
striking on the Delta River floodplains is the abundance
(Fig. 2 and 3). Vegetation cover was generally
of silverberry shrubs (Eleagnus commutata).
negatively correlated with gravel increasing where there
The vegetation of the Delta River floodplain on the
is more sand and silt. Estimates of shrub cover
Washington Range was mapped by Holmes and
(silverberry) in each of the four 3-m 3-m sampled
Benninghoff (1957) using August 1948 aerial photos
plots varied from 15 to 40%. The forb Potentilla
on the Mount Hayes D4-SW topographic map base.
multifida was also abundant and cover by both mosses
Several meadow areas were mapped here in the middle
(up to 70%) and lichens suggests that the gravels here
of the Delta River floodplain. Later Jorgenson et al.
were well stabilized with little flooding.
(2001) mapped the vegetation on Fort Greely and