The land is our most valuable resource. It is indeed much more than this: it is the means of life without which we could never have existed and on which our continued existence and progress depend. The resources of the land are neither inexhaustible nor indestructible, as many men and women have already found to their cost. Resources that had taken many millions of years to accumulate have been squandered or allowed to waste away in a few decades, and this squandering and wastage is continuing wherever definite measures to stop it are not being undertaken. Some of the resources of the land, for example, deposits of metals, coal or oil, are not in practice renewable nor can they be both preserved and used. Many other resources can be preserved and even improved in use. It is essential to the mere continued existence of human life on earth, to say nothing of our continued and increasing prosperity, that the resources of the land should be known as accurately as possible. The limitations of those resources which cannot be renewed should be understood and their unnecessary waste avoided, while renewable resources should be carefully conserved and used without waste or damage. It should be our aim to hand on the natural heritage improved, or at least unimpaired, to future generations.