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