Wednesday, May 29, 2013

Catching up with Juniperus maritima

After learning that I am/was behind the curve on our local northwest Washington juniper, I kept a sharp eye for Juniperus maritima while doing a fast traverse of Fidalgo Island between a visit to Orcas Island and ventures on the Olympic Peninsula. I spotted one on Marine Drive.

Juniperus maritime on Marine Drive south of Anacortes

I have always enjoyed seeing these trees as they are, well different. And now that I have been amply informed that they are not  Juniperus scopulorum (Rocky Mountain juniper) seeing them is even more of a treat.

As has been pointed out to me by much more tree savy folks I was behind on my tree facts. Adams (2007) recognized these junipers in northwest Washington and southwest BC as a distinct species he named Juniperus maritima. He had previously recognized that they were relatively unique and differentiated from J. scopulorum (Rocky Mountain juniper), but the genetic differentiation is apparently great enough to define this as a new species. Hence, I've gone back and updated all my previous mentions of Rocky Mountain juniper changing the posts to reflect this new found information. I like this tree even more now.

Part of my purpose in updating the old post references is that it may add to the knowlege base as to where these trees occur. Adams (2007) provides some discussion as to populations he examined. One aspect of the tree is it appears to have an affinity for ultramafic rock. One of the most robust populations is within Washington Park on the west of Anacortes. And the trees are present in large numbers on Burrows Island and Cypress Island as well; both of which are areas of ultramafic rock. The affinity may be related to the ultramafic rock soil stunts the competition creating opportunity. Likely this is due to the difficulty the ultramafic rock poses to other trees and the pressence of the trees near harsh shoreline conditions points to the need for limited competition. That said, there are very robust populations on the west side of Orcas Island, including locations well away for the shoreline and within areas not underlain by ultramafic rock. 

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