All the trees on the street are usually bare before my next door Norway maple (Acer platanoides) drops its leaves. Look here; it’s still green, in this picture taken yesterday. It doesn’t matter if I rake. The day before the first big snow, this guy typically drops the whole shebang. Whomp! Then we’re shovelling up leaves with the snow, all winter long.
The two fence trees behind the houses are following the same trend. So I wonder what (besides heredity) they have in common to makes them equally retentive?
Perhaps it’s moisture. Moisture stress has a negative impact on leaf abscission – in other words, drought makes plants drop their leaves. Could it be that these three are tapping some hidden spring?
Toronto is riddled with lost rivers and underground streams; with a number in the Beach. South of our house, at the French school our kids attended, a zigzag of mature willow trees suggests to me that a river used to run through it.
The way that history has reshaped the city fascinates me. That’s why I was a sucker for Derek Hayes’ recent Historical Atlas of Toronto (and I should note that this little obsession was not a freebie). Hayes has collected about 300 maps, from the earliest scratched lines on birch bark through site plans for “new” subdivisions such as Rosedale or Lawrence Park. They’re fun to pore over. One shows many streams flowing southward in our area.
So it’s likely that our leaves are trying to tell us something. Like the leftover willows in the schoolyard, the city is full of clues. All we need to do is recognize that there’s a mystery to be solved.