Total fertility rateThe total fertility rate (TFR) of a population is the average number of children that would be born to a female over their lifetime if: they were to experience the exact current age-specific fertility rates (ASFRs) through their lifetime they were to live from birth until the end of their reproductive life. It is obtained by summing the single-year age-specific rates at a given time. , the total fertility rate varied widely across the world, from 0.78 in South Korea to 6.73 in Niger.
FenA fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. The unique water chemistry of fens is a result of the ground or surface water input. Typically, this input results in higher mineral concentrations and a more basic pH than found in bogs. As peat accumulates in a fen, groundwater input can be reduced or cut off, making the fen ombrotrophic rather than minerotrophic.
Forest standA forest stand is a contiguous community of trees sufficiently uniform in composition, structure, age, size, class, distribution, spatial arrangement, condition, or location on a site of uniform quality to distinguish it from adjacent communities. A forest is a "collection of stands" also utilizing the practices of forestry. Stand level modelling is a type of modelling in the forest sciences in which the main unit is a forested stand. A forest stand is commonly described as in 10ths or 10%s.
Alpine climateAlpine climate is the typical weather (climate) for elevations above the tree line, where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate. There are multiple definitions of alpine climate. In the Köppen climate classification, the alpine and mountain climates are part of group E, along with the polar climate, where no month has a mean temperature higher than .
Picea marianaPicea mariana, the black spruce, is a North American species of spruce tree in the pine family. It is widespread across Canada, found in all 10 provinces and all 3 territories. It is the official tree of the province of Newfoundland and Labrador and is that province's most numerous tree. The range of the black spruce extends into northern parts of the United States: in Alaska, the Great Lakes region, and the upper Northeast. It is a frequent part of the biome known as taiga or boreal forest.
