Living tree doctrine

Concept

The living tree doctrine has been deeply entrenched into Canadian constitutional law since the seminal constitutional case of Edwards v Canada (Attorney General), also widely known as the Persons Case, wherein Viscount Sankey stated in the 1929 decision: "The British North America Act planted in Canada a living tree capable of growth and expansion within its natural limits." This is known as the doctrine of progressive interpretation. This means that the Constitution cannot be interpreted in the same way as an ordinary statute. Rather, it must be read within the context of society to ensure that it adapts and reflects changes. If constitutional interpretation adheres only to the framers' intent and remains rooted in the past, the Constitution would not be reflective of society and would eventually fall into disuse.

The "frozen concepts" reasoning runs contrary to one of the most fundamental principles of Canadian constitutional interpretation: that our Constitution is a living tree which, by way of progressive interpretation, accommodates and addresses the realities of modern life.

Lord Sankey LC’s reference to "natural limits" did not impose an obligation to determine, in the abstract and absolutely, the core meaning of constitutional terms.

However, "natural limits" cannot be granted too elastic a definition. In the Marcotte trilogy, it was held that payments by credit card could not be considered to fall within the federal bills of exchange power, as there had been no shift in how a bill of exchange is defined in Canada.