In return, the Canadian government has committed itself for the next seven years and possibly longer (the pact is renewable) to tax Canadian softwood lumber exports should the price fall below $355 for a 1,000 board-feet or if Canada’s share of the US softwood lumber market exceeds 34 percent.
“Canada’s bargaining position was strong, our conditions were clear and this agreement delivers,” a jubilant Prime Minister Stephen Harper told Canada’s parliament. “Canada asked for stable and predictable access to the US market,” he continued. “The United States has agreed to provide Canadian producers with unrestricted access under current market conditions.”
There is a strong element of political boasting and posturing in the Canadian prime minister’s claims. Having for years ignored rulings by various panels and tribunals established under the North American Free Trade Agreement (NAFTA) that its duties on Canadian lumber exports were illegal; Washington has now agreed to withdraw them. But far from access being “unrestricted” as Harper suggests, free trade in lumber will end the moment that the Canadian share of the US market exceeds 34 percent.
http://www.wsws.org/articles/2006/may2006/cana-m30.shtml
Note: http://www.wsws.org/art...

If the US$ drops in value, the $ 355 rate may be reached sooner than anybody can say "softwood lumber agreement".
And by the way, is this ceiling in Can$ 355 or in US$?
---
Expect little from life and get more from it.