Structurally, these forests are rather simple, generally consisting of two layers: an overstory and understory. Some forests may support an intermediate layer of shrubs. Pine forests support a herbaceous understory that is generally dominated by grasses and herbaceous perennials, and are often subject to ecologically important wildfires. Many species of tree inhabit these forests including cedar, cypress, Douglas fir, fir, juniper, pine, podocarpus, spruce, redwood and yew. The understory also contains a wide variety of herbaceous and shrub species.
Temperate coniferous forests around the world sustain the highest levels of biomass in any terrestrial biome and are notable for trees of massive proportions, including Coast Redwood (Sequoia sempervirens), Giant Sequoia (Sequoiadendron giganteum), Douglas fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), Alerce (Fitzroya cupressoides) and kauri (Agathis australis). These forests are quite rare, occurring in small areas of North America, southwestern South America, some mountainous regions of Eurasia, and northern New Zealand. The Klamath-Siskiyou forests of northwestern California and southwestern Oregon are known for their rich variety of plant and animal species, including many endemic species.
In Russia, a coniferous forest, specifically pine or spruce forest is known as bor (Russian: бор). Bors typically grow on well-drained sandy soils, sandy clay soils and mild loams. The names of several Russian historical buildings and localities refer to the word "bor" as the original place where they were built, such as Borovitskaya Tower or Church of the Savior on Bor.