After peace had returned to Britain the timber tariffs did not have long to survive. While at first they were continued, and even strengthened, by 1820 timber became one of the first areas for free trade theory to be applied. In part this was caused by the continued existence of powerful merchants who wanted to see the old Baltic trade restored. The trading interests with the colonies were even stronger, however. The much longer voyage from British North America to Britain meant far more ships and seamen had to be employed. The longer route not only meant more business, but it also was a more profitable route for British merchants, especially since foreigners were still excluded by the Navigation Acts. Military sources, however, disliked Canadian timber. The longer voyage lowered its quality and it was far more susceptible to the dry rot that was one of the navy's more implacable foes. A frigate made of colonial wood tended to have only half the life span of a Baltic ship.