The most popular wood for making these items in the country is pine. This material must be protected from termites and be treated with a water repellent, which can extend the wood’s life. Pine is the cheapest among the various wood. The practicality of this type of tree — a fast-growing. Another specific wood for making post caps is spruce. It can be pressure treated; it is most often used in prefabricated fence panels and cross sections for wood fence caps.