Given the global distribution of human populations and their coincidence with temperate deciduous forests, it is likely that when most people consider the term “forest,” what comes to mind most frequently is the temperate deciduous forest biome. Although not to the level of their tropical counterparts, temperate deciduous forests typically display high plant biodiversity and rates of net primary productivity. They contrast sharply, however, with tropical forests in the distribution of biodiversity and productivity. In tropical forests, greatest plant diversity is associated with the vegetation of greatest productivity—trees. By contrast, the greatest plant diversity—up to 90 percent—in temperate deciduous forests occurs among the plants of least physical stature: the herbaceous species. Given the close association between these forests and their use by human populations, whether for food, fiber, habitat, or recreation, it is not surprising that they have been well studied, particularly in North America, and thus have a rich literature going back many years. However, for the very reason of that intensive use, temperate deciduous forests have proved to be an ecological moving target, as timber harvesting, air pollution, and introduced pests (e.g., insects and parasites) have represented a chronic assault on the structure and function of these ecosystems.
Carbon dioxide fluxes over an ancient broadleaved deciduous woodland in southern England
