Pinaceae is widely distributed, but virtually restricted to the Northern Hemisphere. They are present in parts of Eurasia and North America. They are the major woody components of the Northern coniferous forest biome. The distribution is extensive but discontinuities are apparent. They are widely scattered on isolated mountain ranges, and there are no species in the steppes and desert regins of Central Asia. There are no Pinaceae in the tropics except some species of Pinus in the Caribbean. The concentration of species are in Southwest North America, Southeast North America, and the Sino-Himalayan region.
The growing season is extremely short, but long hours of daylight compensate for this. Pinaceae face much moisture stress due to little precipitation and much evaporation. In the summer, high levels of temperature can lead to evapotranspiration. The adaptation that they evolved were thick cuticles to protect the leaves from water loss. In some of the mountainous regions, as altitude increases, temperature drops, and precipitation increases. The accumulated snow at these high altitudes lingers longer and provides moisture during the dry summer seasons. Climate is the most important factor in distribution of Pinaceae. Edaphic (soil) factors come in second after climate. Pinaceae are capable of growing on nutrient -poor, often acidic soils, either with low or sometimes with extremely high water tables. Optimum conditions for Pinaceae are reached in the Mesothermal coniferous forest biome. Pinaceae tend to grow well after fires and form a dominance in that area.
All species of Pinaceae are monoecious. The male cones consist of a weak rachis with numerous spirally arranged microsporophylls, each with two pollen sacs on the abaxial side. Young male cones are usually reddish or purplish, turning yellowish when pollen is dispersed. In most species, the cones develop in the upper part of the crown.
Most of the species in Pinaceae have ectomycorrhizal symbionts, many of which are macrofungi of order Agaricales. Several species possibly could not survive in some habitats without these symbionts.
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