The first article of the treaty identifies who can take advantage of the treaty.
A tax treaty between two countries doesn’t increase tax but determines who is permitted to reduce double taxation under the treaty.
For instance, Canada’s treaty with the People’s Democratic Republic of Algeria is very straightforward – it applies to persons who are resident of one or both countries.
If something (such as a resident) is not defined, or fully defined, in the treaty, the Income Tax Conventions Interpretation Act requires that it be defined by the Income Tax Act. So, whether or not you are resident of Canada for income tax is the issue – not whether or not you are a citizen or landed immigrant.