Shade tolerance in the context of "Shade (shadow)"

In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy, so understory vegetation is generally shade-tolerant. The understory typically consists of trees stunted through lack of light, other small trees with low light requirements, saplings, shrubs, vines, and undergrowth. Small trees such as holly and dogwood are understory specialists.

In temperate deciduous forests, many understory plants start into growth earlier in the year than the canopy trees, to make use of the greater availability of light at that particular time of year. A gap in the canopy caused by the death of a tree stimulates the potential emergent trees into competitive growth as they grow upward to fill the gap. These trees tend to have straight trunks and few lower branches. At the same time, the bushes, undergrowth, and plant life on the forest floor become denser. The understory experiences greater humidity than the canopy, and the shaded ground does not vary in temperature as much as open ground. This causes a proliferation of ferns, mosses, and fungi and encourages nutrient recycling, which provides favorable habitats for many animals and plants.

A shade house is a horticultural structure which provides a mix of shade and light to provide suitable conditions for shade-loving plants, or to reduce the temperatures under the cover. Typically it will have a frame which supports mesh fabric or wood lath.

Shade houses may also be used in commercial horticulture. For example, vanilla vines need 50% shade and, in deforested areas of Mexico, this is provided by shade houses of 1,000 – 10,000 square metres. These have tree-like support posts or actual living trees. From these, shade cloth walls of 3–5 metres height are suspended and these are black or red to cut the luminosity by half.