A conifer is a tree, or sometimes a shrub, that differs from broadleaf plants in its leaves, seasonal adaptations, and seed production.
Conifer leaves are needle-like or scale-like and are usually retained throughout the year (evergreen), although a few species shed their foliage seasonally. Their small surface area, combined with a waxy coating, helps them conserve water and survive cold, windy, or nutrient-poor environments. These features also allow them to photosynthesize and gain energy during much of the year, in contrast with deciduous plants, whose broader, fast-growing leaves are more efficient in warmer seasons but are shed in the autumn to avoid winter damage and water loss.
Conifers produce their seeds in cones rather than in flowers. Small male cones produce large amounts of pollen that is carried by the wind to larger female cones. The seeds develop within these cones, which then open to release them, either gradually or in response to environmental triggers such as temperature. Once released, these seeds are spread by wind or animals.
Some conifer species also have thick, resin-rich bark and fire-adapted cones, which help them survive in environments prone to wildfire, extreme cold or drought.
Conifers tend to dominate in cold, dry, or nutrient-poor environments where broadleaf trees are less competitive. They are characteristic of boreal forests in northern latitudes, high-elevation mountain forests, temperate coniferous forests such as those in the northwestern United States, and certain coastal and inland sandy areas.
About 600 species of conifers are currently recognized worldwide, including pines, spruces, firs and redwoods. Although this is a small number compared to the tens of thousands of species of broadleaf plants, conifers make up a significant share of the world's forests and contribute substantially to global forest biomass.
The persistent foliage and structural complexity of coniferous forests provide vital shelter, nesting sites, and food sources, especially seeds, but also needles and bark, for a wide variety of animals. These include many species of insects and other invertebrates, as well as amphibians, reptiles, and birds ranging from raptors to specialized species adapted to extracting seeds from cones. Conifer forests also support a diverse range of mammals, from small species such as squirrels and martens to large herbivores like moose and elk, as well as omnivores and predators such as bears and wolves.
Conifers are one of the most endangered groups of trees, with about a third of all species currently at risk of extinction according to recent data from the IUCN Red List. They face a variety of stresses driven by human activity, including climate change, logging, wildfires, mining, urbanization, pest outbreaks and air pollution. In some regions, these pressures are contributing to a shift from conifer forests acting as carbon sinks to becoming sources of greenhouse gas emissions.
Major conservation efforts to protect endangered conifer species include (1) climate resilience projects that identify and prioritize areas likely to remain stable under climate change, (2) targeted restoration methods such as direct seeding in remote areas, (3) the establishment of protected "safe sites" to grow rare species outside of their native ranges and (4) seed banking combined with genetic research to preserve traits that may help species survive future environmental changes.