Deciduous

In the fields of horticulture and botany, the term deciduous (/dɪˈsɪdʒuəs/)[1] means "falling off at maturity"[2] and "tending to fall off",[3] in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flowering; and to the shedding of ripe fruit.

Generally, the term deciduous means "the dropping of a part that is no longer needed" and the "falling away [of a part] after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer,[4] deciduous teeth (baby teeth) in some mammals (including humans); or decidua, the uterine lining that sheds off after birth.

Wood from deciduous trees is used in a variety of ways in several industries including lumber for furniture, construction and flooring (oak), ornamental, bowling pins and baseball bats (maple) and furniture, cabinets, plywood and paneling (birch).

Flickr - Nicholas T - Lofty
Second-growth deciduous forest, Warren County, New Jersey, United States (June 2007)
Autumnal deciduous forest - Laubwand im Herbst
Deciduous forest in autumn, Hesse, Germany
Langaa egeskov rimfrost
Deciduous forest in winter, Denmark

Botany

In botany and horticulture, deciduous plants, including trees, shrubs and herbaceous perennials, are those that lose all of their leaves for part of the year.[5] This process is called abscission.[6] In some cases leaf loss coincides with winter—namely in temperate or polar climates.[7] In other parts of the world, including tropical, subtropical, and arid regions, plants lose their leaves during the dry season or other seasons, depending on variations in rainfall.

The converse of deciduous is evergreen, where foliage is shed on a different schedule from deciduous trees, therefore appearing to remain green year round.[8] Plants that are intermediate may be called semi-deciduous; they lose old foliage as new growth begins.[9] Other plants are semi-evergreen and lose their leaves before the next growing season, retaining some during winter or dry periods.[10] Some trees, including a few species of oak, have desiccated leaves that remain on the tree through winter; these dry persistent leaves are called marcescent leaves and are dropped in the spring as new growth begins.

Forsythia turin
Like a number of other deciduous plants, Forsythia flowers during the leafless season

Many deciduous plants flower during the period when they are leafless, as this increases the effectiveness of pollination. The absence of leaves improves wind transmission of pollen for wind-pollinated plants and increases the visibility of the flowers to insects in insect-pollinated plants. This strategy is not without risks, as the flowers can be damaged by frost or, in dry season regions, result in water stress on the plant. Nevertheless, there is much less branch and trunk breakage from glaze ice storms when leafless, and plants can reduce water loss due to the reduction in availability of liquid water during cold winter days.[11]

Leaf drop or abscission involves complex physiological signals and changes within plants. The process of photosynthesis steadily degrades the supply of chlorophylls in foliage; plants normally replenish chlorophylls during the summer months. When autumn arrives and the days are shorter or when plants are drought-stressed,[12] deciduous trees decrease chlorophyll pigment production, allowing other pigments present in the leaf to become apparent, resulting in non-green colored foliage. The brightest leaf colors are produced when days grow short and nights are cool, but remain above freezing.[13] These other pigments include carotenoids that are yellow, brown, and orange. Anthocyanin pigments produce red and purple colors, though they are not always present in the leaves. Rather, they are produced in the foliage in late summer, when sugars are trapped in the leaves after the process of abscission begins. Parts of the world that have showy displays of bright autumn colors are limited to locations where days become short and nights are cool. In other parts of the world, the leaves of deciduous trees simply fall off without turning the bright colors produced from the accumulation of anthocyanin pigments.

The beginnings of leaf drop starts when an abscission layer is formed between the leaf petiole and the stem. This layer is formed in the spring during active new growth of the leaf; it consists of layers of cells that can separate from each other. The cells are sensitive to a plant hormone called auxin that is produced by the leaf and other parts of the plant. When auxin coming from the leaf is produced at a rate consistent with that from the body of the plant, the cells of the abscission layer remain connected; in autumn, or when under stress, the auxin flow from the leaf decreases or stops, triggering cellular elongation within the abscission layer. The elongation of these cells break the connection between the different cell layers, allowing the leaf to break away from the plant. It also forms a layer that seals the break, so the plant does not lose sap.

A number of deciduous plants remove nitrogen and carbon from the foliage before they are shed and store them in the form of proteins in the vacuoles of parenchyma cells in the roots and the inner bark. In the spring, these proteins are used as a nitrogen source during the growth of new leaves or flowers.[14]

Function

Autumn Leaf 08Nov17
Deciduous plants in mid- to high latitudes shed their leaves as temperatures drop in autumn.[15]

Plants with deciduous foliage have advantages and disadvantages compared to plants with evergreen foliage. Since deciduous plants lose their leaves to conserve water or to better survive winter weather conditions, they must regrow new foliage during the next suitable growing season; this uses resources which evergreens do not need to expend. Evergreens suffer greater water loss during the winter and they also can experience greater predation pressure, especially when small. Losing leaves in winter may reduce damage from insects; repairing leaves and keeping them functional may be more costly than just losing and regrowing them.[16] Removing leaves also reduces cavitation which can damage xylem vessels in plants. This then allows deciduous plants to have xylem vessels with larger diameters and therefore a greater rate of transpiration (and hence CO2 uptake as this occurs when stomata are open) during the summer growth period.

Deciduous woody plants

The deciduous characteristic has developed repeatedly among woody plants. Trees include maple, many oaks and nothofagus, elm, aspen, and birch, among others, as well as a number of coniferous genera, such as larch and Metasequoia. Deciduous shrubs include honeysuckle, viburnum, and many others. Most temperate woody vines are also deciduous, including grapes, poison ivy, Virginia creeper, wisteria, etc. The characteristic is useful in plant identification; for instance in parts of Southern California and the American Southeast, deciduous and evergreen oak species may grow side by side.

Periods of leaf fall often coincide with seasons: winter in the case of cool-climate plants or the dry-season in the case of tropical plants,[17] however there are no deciduous species among tree-like monocotyledonous plants, e.g. palms, yuccas, and dracaenas. The hydrangea hirta is a deciduous woody shrub found in Japan.

Regions

Forests where a majority of the trees lose their foliage at the end of the typical growing season are called deciduous forests. These forests are found in many areas worldwide and have distinctive ecosystems, understory growth, and soil dynamics.[18]

Two distinctive types of deciduous forest are found growing around the world.

Temperate deciduous forest biomes are plant communities distributed in North and South America, Asia, Southern slopes of the Himalayas, Europe and for cultivation purposes in Oceania. They have formed under climatic conditions which have great seasonable temperature variability with growth occurring during warm summers and leaf drop in autumn and dormancy during cold winters. These seasonally distinctive communities have diverse life forms that are impacted greatly by the seasonality of their climate, mainly temperature and precipitation rates. These varying and regionally different ecological conditions produce distinctive forest plant communities in different regions.

Tropical and subtropical deciduous forest biomes have developed in response not to seasonal temperature variations but to seasonal rainfall patterns. During prolonged dry periods the foliage is dropped to conserve water and prevent death from drought. Leaf drop is not seasonally dependent as it is in temperate climates, and can occur any time of year and varies by region of the world. Even within a small local area there can be variations in the timing and duration of leaf drop; different sides of the same mountain and areas that have high water tables or areas along streams and rivers can produce a patchwork of leafy and leafless trees.[19]

Chacachacare dry forest 3

Dry-season deciduous tropical forest

Spring Forest Leaves in Texas Hill Country

Mixed tropical and subtropical deciduous forest in spring, Texas, United States

See also

References

  1. ^ "deciduous (adjective)". Oxford Advanced Learner's Dictionary at OxfordLearnersDictionaries.com.
  2. ^ William Dwight Whitney; Century Dictionary. The Century Dictionary and Cyclopedia: Dictionary. books.google.com. p. 1484.
  3. ^ Debra J. Housel; Capstone Publishers (2009). Ecosystems. books.google.com. ISBN 9780756540685.
  4. ^ Gause, John Taylor (1955). The Complete Word Hunter. A Crowell reference book. New York: Crowell. p. 465.
  5. ^ University of the Western Cape. "Trees that lose their leaves". botany.uwc.ac.za. Archived from the original on 25 March 2013.
  6. ^ Dr. Kim D. Coder; University of Georgia (1999). "Falling Tree Leaves: Leaf Abscission" (PDF). forestry.uga.edu. Archived from the original (PDF) on 18 May 2013.
  7. ^ Science Daily. "Science Reference: Deciduous". sciencedaily.com.
  8. ^ J. Robert Nuss; Pennsylvania State University (2007). "Evergreen Shrubs and Trees for Pennsylvania" (PDF). psu.edu.
  9. ^ "The Illinois - North Carolina Collaborative Environment for Botanical Resources: Openkey Project. Glossary of Botanical Terms. Page 22" (PDF). Retrieved 2013-07-17.
  10. ^ Weber, William. 2001. African rain forest ecology and conservation an interdisciplinary perspective. New Haven: Yale University Press. page 15.
  11. ^ Lemon, P. C. (1961). "Forest ecology of ice storms". Bulletin of the Torrey Botanical Club. Bulletin of the Torrey Botanical Club, Vol. 88, No. 1. 88 (21): 21. doi:10.2307/2482410. JSTOR 2482410.
  12. ^ Mohammad Pessarakli (2005). Handbook of photosynthesis. CRC Press. pp. 725–. ISBN 978-0-8247-5839-4. Retrieved 9 October 2010.
  13. ^ Donald W. Linzey (1 April 2008). A natural history guide to Great Smoky Mountains National Park. Univ. of Tennessee Press. pp. 27–. ISBN 978-1-57233-612-4. Retrieved 9 October 2010.
  14. ^ Srivastava, Lalit M. (2002). Plant growth and development. Hormones and environment. Amsterdam: Academic Press. p. 476. ISBN 0-12-660570-X.
  15. ^ Bonan, Gordon (2015). Ecological Climatology: Concepts and Applications. Cambridge University Press. p. 294. ISBN 9781316425190.
  16. ^ Labandeira, C. C.; Dilcher, D. L.; Davis, D. R.; Wagner, D. L. (1994). "Ninety-seven million years of angiosperm-insect association: paleobiological insights into the meaning of coevolution". Proceedings of the National Academy of Sciences of the United States of America. 91 (25): 12278–12282. Bibcode:1994PNAS...9112278L. doi:10.1073/pnas.91.25.12278. PMC 45420. PMID 11607501.
  17. ^ Cundall, Peter (2005). Flora: The Gardener’s Bible: Over 20,000 Plants. Ultimo, NSW, Australia: ABC Publishing. ISBN 0-7333-1094-X.
  18. ^ Röhrig, Ernst; Ulrich, Bernhard, eds. (1991). Temperate deciduous forests. Ecosystems of the world, 7. Amsterdam: Elsevier. ISBN 0-444-88599-4.
  19. ^ Bullock, Stephen H.; J. Arturo Solis-Magallanes (March 1990). "Phenology of Canopy Trees of a Tropical Deciduous Forest in Mexico". Biotropica. 22 (1): 22–35. doi:10.2307/2388716. JSTOR 2388716.

External links

Banda Sea

The Banda Sea is a sea in the Maluku Islands of Indonesia, connected to the Pacific Ocean but surrounded by hundreds of islands, as well as the Halmahera and Ceram Seas. It is about 1000 km (600 mi) east to west, and about 500 km (300 mi) north to south.

Chota Nagpur Plateau

The Chhota Nagpur Plateau is a plateau in eastern India, which covers much of Jharkhand state as well as adjacent parts of Odisha, West Bengal, Bihar and Chhattisgarh. The Indo-Gangetic plain lies to the north and east of the plateau, and the basin of the Mahanadi River lies to the south. The total area of the Chota Nagpur Plateau is approximately 65,000 square kilometres (25,000 sq mi).

Deciduous teeth

Deciduous teeth, commonly known as milk teeth, baby teeth and temporary teeth, are the first set of teeth in the growth development of humans and other diphyodont mammals. They develop during the embryonic stage of development and erupt—that is, they become visible in the mouth—during infancy. They are usually lost and replaced by permanent teeth, but in the absence of permanent replacements, they can remain functional for many years.

Evergreen

In botany, an evergreen is a plant that has leaves throughout the year that are always green. This is true even if the plant retains its foliage only in warm climates, and contrasts with deciduous plants, which completely lose their foliage during the winter or dry season. There are many different kinds of evergreen plants, both trees and shrubs. Evergreens include:

most species of conifers (e.g., pine, hemlock, blue spruce, and red cedar), but not all (e.g., larch)

live oak, holly, and "ancient" gymnosperms such as cycads

most angiosperms from frost-free climates, such as eucalypts and rainforest trees

clubmosses and relativesThe Latin binomial term sempervirens, meaning "always green", refers to the evergreen nature of the plant, for instance

Cupressus sempervirens (a cypress)

Lonicera sempervirens (a honeysuckle)

Sequoia sempervirens (a sequoia)Leaf persistence in evergreen plants varies from a few months to several decades (over thirty years in the Great Basin Bristlecone Pine).

FDI World Dental Federation notation

FDI World Dental Federation notation is a dental notation widely used by dentists internationally to associate information to a specific tooth.Developed by the FDI World Dental Federation, World Dental Federation notation is also known as ISO 3950 notation.

Orientation of the chart is traditionally "dentist's view", i.e. patient's right corresponds to notation chart left. The designations "left" and "right" on the chart below correspond to the patient's left and right.

Hardwood

Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood contrasts with softwood (which is from gymnosperm trees).

Kathiawar-Gir dry deciduous forests

The Kathiawar-Gir dry deciduous forests is a mostly arid ecoregion in northwestern India that stretches over 103,100 sq mi (267,000 km2) across Gujarat, Rajasthan and Madhya Pradesh. The dry deciduous forests in the region are dominated by teak, and thorny trees and scrub in drier areas.

Lesser Sunda Islands

The Lesser Sunda Islands (Indonesian: Kepulauan Nusa Tenggara "southeastern archipelago"

or Kepulauan Sunda Kecil "lesser Sundanese archipelago")

are a group of islands in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up the Sunda Islands. The islands are part of a volcanic arc, the Sunda Arc, formed by subduction along the Sunda Trench in the Java Sea.

The main Lesser Sunda Islands are, from west to east: Bali, Lombok, Sumbawa, Flores, Sumba, Timor, Alor archipelago, Barat Daya Islands, and Tanimbar Islands.

List of ecoregions in India

The Himalaya, which runs across India's northern tier, is the boundary between two of the Earth's great ecozones — the Palearctic, which covers most of temperate-to-arctic Eurasia, and Indomalaya, which covers most of the Indian subcontinent and extends into Indochina, Sundaland (Malaysia and western Indonesia) and the Philippines.

Lower Gangetic plains moist deciduous forests

The Lower Gangetic plains moist deciduous forests is a tropical moist broadleaf forest ecoregion of Bangladesh and eastern India. The ecoregion covers an area of 254,100 square kilometres (98,100 sq mi), covering most of Bangladesh and the Indian states of West Bengal, Bihar and Tripura, and extending into adjacent portions of Assam, Uttar Pradesh and Orissa states.

Palearctic realm

The Palearctic or Palaearctic is one of the eight biogeographic realms on the Earth's surface, first identified in the 19th century, and still in use today as the basis for zoogeographic classification. The Palearctic is the largest of the eight realms. It stretches across all of Europe, Asia north of the foothills of the Himalayas, North Africa, and the northern and central parts of the Arabian Peninsula.

The realm consists of several ecoregions: the Euro-Siberian region; the Mediterranean Basin; the Sahara and Arabian Deserts; and Western, Central and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions. Some of the rivers were the source of water for the earliest recorded civilizations that used irrigation methods.

Sumba

Sumba (Indonesian: Pulau Sumba) is an island in eastern Indonesia. It is one of the Lesser Sunda Islands and is in the province of East Nusa Tenggara. Sumba has an area of 11,059.6 square kilometres (4,270.1 square miles), and the population was estimated to be 755,849 in 2015. To the northwest of Sumba is Sumbawa, to the northeast, across the Sumba Strait (Selat Sumba), is Flores, to the east, across the Savu Sea, is Timor, and to the south, across part of the Indian Ocean, is Australia.

Temperate broadleaf and mixed forest

Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions.These forests are richest and most distinctive in central China and eastern North America, with some other globally distinctive ecoregions in the Caucasus, the Himalayas, southern Europe, and the Russian Far East.

Temperate deciduous forest

Temperate deciduous or temperate broad-leaf forests are a variety of temperate forest dominated by trees that lose their leaves each year. They are found in areas with warm moist summers and cool winters. The six major areas of this forest type occur in the Northern Hemisphere: North America, East Asia, Central and Western Europe (except Brittany, Cornwall, Wales, Ireland and western Scotland), Denmark, southern Sweden and southern Norway. Smaller areas occur in Australasia and southern South America. Examples of typical trees in the Northern Hemisphere's deciduous forests include oak, maple, beech and elm, while in the Southern Hemisphere, trees of the genus Nothofagus dominate this type of forest. The diversity of tree species is higher in regions where the winter is milder, and also in mountainous regions that provide an array of soil types and microclimates. The largest intact temperate deciduous forest in the world is protected inside of the six-million-acre Adirondack Park in Upstate New York in the United States.

Temperate forest

A temperate forest is a forest found between the oceans and arctic regions in the area of space with the widest seasonal changes, the temperate zone. They fall into one of several main types: deciduous, coniferous, broadleaf and mixed forest and rainforest.

Timor

Timor is an island at the southern end of Maritime Southeast Asia, north of the Timor Sea. The island is divided between the sovereign states of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, also known as West Timor, constitutes part of the province of East Nusa Tenggara. Within West Timor lies an exclave of East Timor called Oecusse District. The island covers an area of 30,777 square kilometres (11,883 square miles). The name is a variant of timur, Malay for "east"; it is so called because it lies at the eastern end of the Lesser Sunda Islands. Mainland Australia is less than 500 km away, separated by the mentioned Timor Sea.

Tooth fairy

The Tooth Fairy is a fantasy figure of early childhood in Western and Western-influenced cultures. The folklore states that when children lose one of their baby teeth, they should place it underneath their pillow or on their bedside table and the Tooth Fairy will visit while they sleep, replacing the lost tooth with a small payment.The tradition of leaving a tooth under a pillow for the Tooth Fairy to collect is practiced in various countries.

Tropical and subtropical dry broadleaf forests

The tropical and subtropical dry broadleaf forest is a habitat type defined by the World Wide Fund for Nature and is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive several hundred centimeters of rain per year, they have long dry seasons which last several months and vary with geographic location. These seasonal droughts have great impact on all living things in the forest.

Deciduous trees predominate in most of these forests, and during the drought a leafless period occurs, which varies with species type. Because trees lose moisture through their leaves, the shedding of leaves allows trees such as teak and mountain ebony to conserve water during dry periods. The newly bare trees open up the canopy layer, enabling sunlight to reach ground level and facilitate the growth of thick underbrush. Trees on moister sites and those with access to ground water tend to be evergreen. Infertile sites also tend to support evergreen trees. Three tropical dry broadleaf forest ecoregions, the East Deccan dry evergreen forests, the Sri Lanka dry-zone dry evergreen forests, and the Southeastern Indochina dry evergreen forests, are characterized by evergreen trees.Though less biologically diverse than rainforests, tropical dry forests are home to a wide variety of wildlife including monkeys, deer, large cats, parrots, various rodents, and ground dwelling birds. Mammalian biomass tends to be higher in dry forests than in rain forests, especially in Asian and African dry forests. Many of these species display extraordinary adaptations to the difficult climate.This biome is alternately known as the tropical bane forest biome or the tropical and subtropical deciduous forest biome.

Tropical and subtropical moist broadleaf forests

Tropical and subtropical moist broadleaf forests (TSMF), also known as tropical moist forests, are a tropical and subtropical forest habitat type defined by the World Wide Fund for Nature. The habitat type is sometimes known as jungle.

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