Direct answer: Wood tar is the broad name for tar made from wood by destructive distillation or carbonisation. Pine tar, birch tar, beech tar, and other tree tars all sit inside this family.
People learned to make wood tar by controlling heat, wood, and airflow. When wood is heated without enough oxygen for normal burning, it breaks down into charcoal, gases, watery acids, oils, and tarry liquids. The exact tar depends on the tree species, the moisture, the temperature, and the equipment used.
Wood tar has been valued as a preservative, water-shedding coating, rope dressing, sealant, adhesive ingredient, and source of further distillation products. In maritime history, it helped maintain wooden ships and rigging. In archaeology, selected wood tars help explain early adhesives and craft technologies.
Wood tar is a category, not a single recipe. Pine tar usually means a coniferous preservative tar. Birch tar often means an adhesive or pitch. Beech tar is connected with wood creosote. Hardwood and softwood tars can smell, dry, and perform differently.
In short: A broad category made from wood. Produced by heating wood in limited oxygen. Includes pine tar, birch tar, beech tar, and other tree-based tars. Historically used on wood, rope, boats, and craft objects.