The May Meeting 2001

A fascinating account of the natural history of our BC environs was delivered by Richard Hebda, distinguished palynologist, derived from his research into the primordial ooze of Saanich Inlet. A sophisticated seaworthy drilling rig was employed to extract, from the bottom of the inlet, a long core of some 70 to 80 metres, some 10 times the usual core lengths retrieved from interior lakes. The anaerobic condition of the sediment depths has preserved intact the pollen grains of some thousands of years, allowing a clear understanding of the plant environments through recent ages.

An unusual section of the retrieved core revealed a sudden change lasting a few decades some 11,000 years ago (though long before Adam & Eve, a mere twinkling of an eye in geological time). This change involved a rapid warming throughout BC, thawing the glaciers and causing great floods which eroded the softer rock to create the huge interior river canyons. The thrust of such floods easily reached our Island across a much narrower sea, creating the Saanich ‘trough’, from its earlier ice covering. Pollen grains from this section revealed a previous land cover of hickory, walnut, basswood and linden – species decidedly unknown to the modern scene. The post flood devastation would have left great expanses of bare rock meadows thinly covered by bracken and bunch grass, with a few scattered Sitka spruce, but no forests.

The first Douglas firs appeared some 10,000 years ago; between 9300 and 7500 (ago) some Oregon ash would have been seen, and the meadows began to sport camas, buttercup and cow parsley. And then the oaks arrived and by the 6200 year mark their forests may have reached a peak with the grasses disappearing, but bracken fern surviving. As the climate changed again, wetter and cooler surrounds stimulated the Douglas fir and by 5000, the rainforest with expanses of western cedar and western hemlock took hold. The Sooke hills are typical of this scene.

Garry oaks set in their meadows of wildflowers have been reduced by the encroachment of urban tracts, automobiles and such foreign interlopers as wild broom. Pestilence and disease have come and gone, culling the weak, but perhaps strengthening the survivors. We are familiar with the gall wasp and phylloxera visitations of the last decade. And a nasty strain of phytophthera appears to be marching northward from California. Change is inexorable, but there is much that can be done to preserve the nobility of these great tree meadows. The Land Conservancy was cited as an effective agency for the support of this honourable objective.

The inquiring minds of the Society members were well stimulated by Richard Hebda’s fine exposition, delivered with eloquence and wit.