Thursday, February 18, 2016

Canada Yew

In a narrow, cool, damp valley in the Big Woods grow a few scattered plants of Canada yew (Taxus Canadensis). The plants are there because the species requires the cool moist shady habitat provided by the valley’s stream and forest dominated by eastern hemlock and black and yellow birch. The valley’s steep hillsides are a jumble of large rocks and scattered boulders –

The rocks are as important (possibly more so) as the habitat since white-tailed deer find Canada yew extremely palatable and, where they can access the plants, browse it into oblivion. In this valley, deer are kept away from the yew by the treacherous footing among the rocks. In other places Canada yew grows on high ledges bordering streams – again where it’s inaccessible to deer. 

Canada yew is a spreading shrub, here never getting more than four feet tall. The wide-spreading branches frequently take root where they come in contact with the soil and may provide the primary means by which the plants reproduce. The plant does produce seed; a single seed contained within a fleshy red “berry” more properly called an aril which is readily eaten by numerous species of birds.

Many of the few people who see Canada yew assume that the short plants are young or stunted hemlocks which they superficially resemble. But, eastern hemlock needles have two narrow pale lines on the underside while Canada yew needles are a uniform green on both surfaces –

            Canada Yew                 Underside of  Needles                Eastern Hemlock

The new twigs of Canada yew are also stout and green, not thin and tan as are hemlock twigs –

         Canada Yew                             Twigs                             Eastern Hemlock

Finding Canada yew is a rare treat for those of us who live where deer populations have been high for many years. 
In Northcentral Pennsylvania the plants share their habitat with fishers, Blackburnian and black-throated green warblers, and barred owls – all species worth knowing.

1 comment:

David M. Gascoigne, said...

Thanks for the tree identification course. I am always glad to have these kinds of pointers. It's a really interesting post.