Juniperus maritima, the seaside juniper, a new species from Puget Sound, North America. See: Phytologia: Juniperus maritima (PDF)
Not surprising - this population of (previously) "J. scopulorum" stands out conspicuously separate in its ecology and climatic adaptation. If anything, it's surprising it hadn't been split off long ago.
"Both J. scopulorum and J. virginiana are weedy junipers that invade old fields and disturbed roadsides. In contrast, the seaside juniper is not weedy and usually appears as if it is relictual (i.e., older trees, with few or no seedlings). The Puget Sound juniper's habitat seems to be very restricted and has only been collected in a few locations (Fig. 7)." Account does not include population at Juniper Beach, Camano Island, and numerous scattered younger individuals in fields and wetlands near there and elsewhere south and east of distribution shown on map, as near Everett, WA, where multiple individuals can be seen in various locations from Interstate 5. While certainly not numbering in the thousands and forming nuisance thickets, these ARE younger individuals appearing on sites not currently supporting groves of mature specimens. Spontaneous Chinese junipers (J. chinensis) also appear in open places in the Seattle area, including vicinity of freeways but have a different appearance that can be discerned from a speeding car. And I suppose there may not be much distribution overlap between the two species here. Cultivated examples of the native - including some rather large ones - are fairly common on properties in/near its natural distribution area but are quite rare in Seattle. Off the top of my head I can think of noticing only a single example there.
Can anyone post some photos? I'm also intrigued by Adam's comment that the "seeds usually exserted from the cone" - at least in other junipers this ('gymnocarpy') is usually associated with insect or mite damage, with exserted seeds being sterile (see left-hand cone in photo below). It would be interesting if this does not apply in this case. Gymnocarpy photo (in Juniperus angosturana): http://www.pinetum.org/Jeff8/JUangosturanaGaleanaCone1.jpg
We have found Juniperus maritima typically on abandoned First Nation middens on the NW coast of Saanich Peninsula and on the Gulf Islands of BC. Are these conifers growing in the middens because of the alkaline condition or greater drainage created by the shells?
Not sure about that, but there are unique plant community assemblages along the coast of South Carolina that are also correlated with ancient middens.
Conditions on other sites where the tree grows seem to indicate it would be the mineral content of the shells and not any possible effect on drainage.
The local people I have spoken with don't seem to think so but I still think the idea plausible. Thanks for replying.
Don't forget the occurrence of J. maritima in the interior of the Olympic Peninsula, on steep rocky slopes far away from any likely site of former human habitation.
It survived the last glaciation up high in the Olympics, then went into the lowlands after the ice retreated.