An old canoe or a small wooden boat hanging from the rafters of a barn or garage seems to trigger in me an involuntary nerve response—call it “restoration project syndrome”— for which I have yet to find a cure. A note from reader Peter Fenwood of Rockland, Maine, seems to show he is infected with the same bug:
I am fortunate to have in my care a 15' wood-and-canvas Old Town square-sterned runabout that dates from the 1940s, when my grandfather purchased it for use on Cold Stream Pond in Enfield, where he had built a camp in the ’30s. The boat underwent a restoration about 40 years ago during which the interior was stripped, and rather than varnishing the interior it was treated with boiled linseed oil and turpentine. This has darkened over time, as it is wont to do, making the interior almost black throughout. My brother would like to bring it back to its original golden tones, but we are at an impasse as to how to do this, if it is indeed possible. Do you know how this can be done?
Some of the darkening Peter sees in this classic Old Town boat may be accumulated dust and other airborne debris, but I am quite certain most of it is caused by embedded spores produced by a black-mold fungus.
Molds and wood-staining fungi belong to a group called ascomycetes. Unlike basidiomycete fungi, ascomycetes don’t cause wood decay. Staining fungi can penetrate deep into sapwood and their colored hyphae (fungal strands) are the cause of blue or other colors of staining in sapwood. Molds, on the other hand, inhabit the surface of wood with little or no hyphal penetration. They have colorless hyphae but produce colored spores, called conidia, on the surface. Black molds are most pernicious because the conidia they produce are embedded in a slime droplet that dries to a protective covering, hindering mold removal.
My last foray into the realm of mold and mildew was in 1991 (see WB No. 100). In the intervening years, a controversial phenomenon called “sick building syndrome” has captured the interest of the news media and prompted, in some cases, the closure of schools or abandonment of residences. The culprit, Stachybotrys chartarum, a species of mold fungus that produces black spores, may cause illnesses in humans and other animals.
First described in 1837 after being found on wallpaper collected from a house in Prague, this black mold became more widely known in the 1930s when outbreaks of a new disease of horses in Ukraine and other parts of Eastern Europe was traced to S. chartarum growing on straw and other grain fodder. Symptoms in horses included irritations of the mouth, throat, and nose; shock; dermal necrosis; a decrease in leucocytes; hemorrhage; and, in some cases, death.