The most common types of soils in coniferous forests are called podzol soils. Podzol soils are defined by their thin surface layers and high acid content. Their composition varies depending on their location on earth and is subject to variation from temperature differences and geographical factors, such as terrain and the presence or absence of air, water and minerals.
In addition to being thin and relatively acidic, podzol soils are quite infertile. The infertile nature of these soils makes them ideal for supporting the growth of strong and sturdy evergreen trees, which are, like their supporting soils, quite versatile to environmental conditions and can thrive in extreme temperatures and subpar growing conditions. Podzol soils have very few minerals and nutrients, as the few nutrients that collect on and just below their surfaces tend to wash away in the spring following snowmelts. Most forests contain soils rich in decomposing plant and animal matter, which contain a wealth of nutrients, but conifer needles are slow to decompose, depriving podzol soils of the key nutrients and substances required to support and maintain a diversity of floral life. Lastly, coniferous needles shed acid rain from their surfaces. The acid rain falls to the forest floor and adds to the acidity of podzol soil.