Canopy (forest)
Encyclopedia
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
, the canopy is the aboveground portion of a plant community or crop
Crop
Crop may refer to:* Crop, a plant grown and harvested for agricultural use* Crop , part of the alimentary tract of some animals* Crop , a modified whip used in horseback riding or disciplining humans...
, formed by plant crowns
Crown (botany)
The crown of a plant refers to the totality of the plant's aboveground parts, including stems, leaves, and reproductive structures. A plant canopy consists of one or more plant crowns growing in a given area....
.
For forests, canopy also refers to the upper layer or habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
zone, formed by mature tree crowns
Crown (botany)
The crown of a plant refers to the totality of the plant's aboveground parts, including stems, leaves, and reproductive structures. A plant canopy consists of one or more plant crowns growing in a given area....
and including other biological organisms (epiphytes, lianas, arboreal animals, etc.).
Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
or group of trees. Shade tree
Shade tree
A shade tree is any tree grown specifically for its shade. This term usually applies to large trees with spreading canopies. Shade trees are effective in reducing the energy used in cooling homes....
s normally have a dense canopy that blocks light from lower growing plants.
Canopy structure
Canopy structure is the organization or spatial arrangement (three-dimensional geometry) of a plant canopy. Leaf area index (LAI)Leaf Area Index
Leaf Area Index The Global Climate Observing System defines LAI as "one half the total green leaf area per unit groundsurface area. On sloping surfaces, the LAI should be projected to the normal to the slope. LAI is expressed in terms of square meters of leaf per square meter of ground...
, leaf area per unit ground area, is a key measure used to understand and compare plant canopies.
Canopy layer of forests
Dominant and co-dominant canopy trees form the uneven canopy layer. Canopy trees are able to photosynthesizePhotosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
relatively rapidly due to abundant light, so it supports the majority of primary productivity in forests. The canopy layer provides protection from strong winds and storms, while also intercepting sunlight and precipitation, leading to a relatively sparsely vegetated understory
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
layer.
Forest canopies are home to unique flora and fauna not found in other layers of forests. The highest terrestrial biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
resides in the canopy of tropical rainforests. Many rainforest animals have evolved to live solely in the canopy, and never touch the ground.
The canopy of a rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
is typically about 10m thick, and intercepts around 95% of sunlight. The canopy is below the emergent layer, a sparse layer of very tall trees, typically one or two per hectare
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
. With an abundance of water and a near ideal temperature in rainforests, light and nutrients are two factors that limit tree growth from the understory to the canopy.
In the permaculture
Permaculture
Permaculture is an approach to designing human settlements and agricultural systems that is modeled on the relationships found in nature. It is based on the ecology of how things interrelate rather than on the strictly biological concerns that form the foundation of modern agriculture...
and forest gardening
Forest gardening
Forest gardening is a food production and agroforestry system based on woodland ecosystems, incorporating fruit and nut trees, shrubs, herbs, vines and perennial vegetables which have yields directly useful to humans...
community, the canopy is the highest of seven layers.
See also
- Canopy gapGap (ecology)In forest ecology, a treefall gap is an opening in the forest canopy structure devoid of large trees. Gaps are formed after large trees die and fall which allows the regrowth trees and other plants as the shade is removed.-References:...
- Canopy researchCanopy researchCanopy research is the field of scientific research based upon data collected in the canopy of trees.-Objects:* Description of plant and animal species residing in the tree-summits. Mainly ancient forests and tropical forests are studied....
- Canopy (grape)
- Canopy walkwayCanopy walkwayCanopy walkways are bridges between trees in the canopy of a forest; mostly linked up with platforms inside or around the trees. They were originally intended as access to the upper regions of ancient forests for scientists conducting canopy research. Eventually, because they provided only...
- Hemispherical photographyHemispherical photographyHemispherical photography, also known as fisheye or canopy photography, is a technique to estimate solar radiation and characterize plant canopy geometry using photographs taken looking upward through an extreme wide-angle lens . Typically, the viewing angle approaches or equals 180-degrees, such...
- Leaf area indexLeaf Area IndexLeaf Area Index The Global Climate Observing System defines LAI as "one half the total green leaf area per unit groundsurface area. On sloping surfaces, the LAI should be projected to the normal to the slope. LAI is expressed in terms of square meters of leaf per square meter of ground...
- RainforestRainforestRainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
- UnderstoryUnderstoryUnderstory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
External links
Further reading
Lowman, M.D., and H.B. Rinker (editors). 2004. Forest Canopies (Second edition). Academic Press. ISBN 0-12-457553-6, ISBN 978-0-12-457553-0Moffett, M.W. 1994. The High Frontier: Exploring the Tropical Rainforest Canopy. Harvard University Press, Cambridge, MA.
Russell, G., B. Marshall, and P.G. Jarvis (editors). 1990. Plant Canopies: Their Growth, Form and Function. Cambridge University Press. ISBN 0-521-39563-1, ISBN 978-0-521-39563-2