The oldest tree in the world is China's gingko
The Ginkgo tree is a related to the group of plants classified as gymnosperms, or conifers. The seeds of gymnosperms (which means "naked seed") are not surrounded by a fruit as are the seeds of flowering plants, but are protected by cones, or by a fleshy seed coat. Ginkgo trees are dioecious; male and female cones are found on separate plants. (Most gymnosperms and flowering plants have both sexes on the same plant.) Although frequently called a fruit, it is the seed coat of the Ginkgo that is fleshy; the mature seeds resemble small plums or cherries. Unfortunately (for human noses), the seed coat decomposes at maturity, producing butyric (or butanoic) acid, which smells like rancid butter, and caproic (hexanoic)acid, which smells like old gym socks. These odors probably attracted a dispersal agent when Ginkgos lived in the wild. Today the odors attract chain saw operating humans. For this reason, most Ginkgos now planted are male trees.
In addition to its striking appearance, and value as an ornamental street and lawn tree, the seeds of the Ginkgo are eaten throughout much of Asia. You can sometimes find them fresh (minus the seed coat) at Uwajimaya, or in cans, marketed as white nuts.