Niagara Issues - White Cedar
P. M. Eckel
Res Botanica
Missouri Botanical Garden
March 8, 2003

Return to home

Niagara Issues - White Cedar


The series of images below show population of White Cedar (Thuja occidentalis), an evergreen species mostly associated with swamps on level ground. Their occurrence in these substrates seems counter-intuitive were it not for year-round seepage. Special tufa-forming moss communities also enjoy such discharges and form the substrate for vascular species of interest, such as Cystopteris bulbifera, one of the most distinctive ferns of the gorge and the Niagara Escarpment, as well as Lobelia kalmii, the type locality of which was thought by some to have derived from Niagara Falls. The rare fern Pellaea glabella also grows on such forbidding exposures and nowhere else here. In spring the gray rock-face is illuminated by the nodding scarlet blooms of Aquillegia canadensis.


Although populations of White Cedar have been found to show ancient growth along the Niagara Escarpment in Ontario, it remains problematical whether the Niagara populations display similar ages. Note in the final two images specimens that appear to be juveniles. Since such trees grow in the caprock, they are vulnerable to sapping by authorities who judge caprock ledges to be dangerous, the so-called 'table rocks' that project out into space, their softer supporting substrates having eroded away from under them.


Gorge forests display formation in horizontal tiers: above the gorge rim there is Sugar Maple (Acer saccharum) and Red Oak (Quercus borealis) dominated woods with certain interesting Oak-Hickory assemblages as in the southern sector of Whirlpool woods including aboriginal trees allowed to flourish on the Robert Moses Parkway there. The next tier are the Thuja-dominated caprock trees. Talus slopes display Walnut  species (Juglans nigra and cinerea), Hop-hornbeam (Ostrya virginiana), Basswood (Tilia americana) and a host of secondary species. The bottom tier along the shoreline is Paper Birch (Betula papyrifera), Yellow Birch (Betula allegheniensis), lovely species of Shadbush (Amelanchier spp.), three species of Poplar (Populus tremuloides, P. deltoids, P. grandidentata) and various willows, including the big foreign species Salix fragilis and S. alba, but also shrubby native species such as Pussy willow (Salix discolor) and Bebb's Willow (Salix bebbiana).


This does not include extensive areas of replacement forest dominated by Box Elder (Acer negundo) and Norway Maple (Acer platanoides).











A note of caution for those who might expect to identify and count White Cedar tree populations from photographs or from a distance, as with binoculars from the base or top of the gorge, or across the river to the opposite shore. The Juniper is also an evergreen tree with similar shape and texture. It has needle-shaped leaves, whereas those of the White Cedar are scale-shaped. This specimen at Devil's Hole in the town of Lewiston above the escarpment is a Juniper tree (Juniperus virginiana).