The heating (dry distilling) of wood causes tar and pitch to drip away from the wood and leave behind charcoal. Birchbark is used to make birch-tar, a particularly fine tar. The terms tar and pitch are often used interchangeably. However, pitch is considered more solid, while tar is more liquid. Traditionally, pitch that was used for waterproofing buckets, barrels and ships was drawn from pine. It is used to make Cutler's resin.
A 10th-century redaction of an earlier Greek Byzantine agricultural work brings down the ancient method of applying pitch to ceramic wine casks:
The ceramic ware was pitched, both inside and out, immediately while they were removed from the kiln and still hot.