Bark fragments in various fractions. Bark is derived from the pine tree, the Pinus Pinastre, originating from France, Portugal or Spain. Bark is available in various fractions and can be used for various purposes. Bark with a relatively fine structure can be used for mixing into potting soil mixtures. This gives the potting soil an open, light structure and a high degree of stability. Fine bark is also used as a top layer in pots and planters. The coarse fractions are used to decorate gardens or as a top layer for paths and playgrounds.