Naturespeak

Of Cubical Butt Rot and other things

Whistler Naturalist Society

The recent toppling of a massive Sitka Spruce in the White Gold Alluvial Fan clearly illustrates how wind and rot play a key role in maintaining the health of a mature coniferous forest.

Wind events combined with various root and trunk disease help bring old trees down, creating openings in the forest canopy. Sunlight can then reach the forest floor, allowing development of understorey plants and a new generation of trees.

One sure way to identify disease in a tree is the development of "Conks," correctly called sporophores. These conks appear as shelf-like developments on the trunk of trees affected by various rots. Mostly perennial, many conks are persistent and very dense. Some growing fairly large, these fruiting bodies are a reliable indicator of the presence of rot. Our most disease-susceptible conifer, the Western Hemlock, shows off its conks in most forest locations in the valley.

Some common rots found in our forests go by very interesting names, like Pocket Rot (not to be confused with the effects of time spent in Whistler’s high end stores). Also to be found is White Butt Rot, (no comments please), while Brown Stringy Trunk Rot produces the hoof-like sporophore known as the "Indian Paint Fungus." This name derives from the native Indian use of the ground-up fruiting body in the preparation of paint pigments. Trunk rots, heart rots and insect activity create soft areas within the stems of standing trees, these areas are accessed by primary cavity excavators, like Pileated woodpeckers, for food and nesting purposes. Standing rotten wood is extremely important to the continued existence of many of our forest inhabitants. In British Columbia more than 90 species of wildlife, or approximately 16 per cent of the province’s birds, mammals, and amphibians depend on wildlife trees.

This Spruce measures 130cm DBH (diameter at breast height) and fell bank to bank over Fitzsimmons Creek. Although it clearly demonstrates absence of conks this does not mean the tree is free of rot.

Some conks are produced annually and appear in the duff layer around the tree base. At least one type of rot (possibly Brown Cubical Butt Rot) was present with the likelihood of two different rots contributing to the failure of this once dominant giant of the forest. This spectacular demonstration of the forces of nature is currently blocking the nature trail on the west side of Fitzsimmons Creek.

In the absence of visual clues like conks, depressions or flat planes in the trunk, as well as reduced overall tree vigour, can provide clues to the presence of disease. A distress crop of cones may occasionally accompany discoloration of the foliage. A disease centre can also be present, with other downed trees in the immediate vicinity providing clues to the presence of rot.

Upcoming Events

Thursday, Feb. 27, 7:30 p.m. at Millennium Place

Dr. Neville Winchester: "The Last Unexplored Biotic Frontier: Science in the High Canopy of Ancient Rainforests." Dr. Winchester is the scientist who first discovered a huge variety of previously unknown insects in the canopies of old-growth trees in the Carmannah Valley. Neville will describe his discoveries in the Carmannah and other ancient rainforests, as well as the climbing methods he has pioneered. Suggested donation $7 ($5 for members); children free. Doors open at 7 p.m.