Related Research Articles
Bark is the outermost layer of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner bark, which in older stems is living tissue, includes the innermost layer of the periderm. The outer bark on older stems includes the dead tissue on the surface of the stems, along with parts of the outermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the living periderm is also called the rhytidome.
Arboriculture is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants. The science of arboriculture studies how these plants grow and respond to cultural practices and to their environment. The practice of arboriculture includes cultural techniques such as selection, planting, training, fertilization, pest and pathogen control, pruning, shaping, and removal.
Betula pendula, commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found at higher altitudes. Its range extends into Siberia, China, and southwest Asia in the mountains of northern Turkey, the Caucasus, and northern Iran. It has been introduced into North America, where it is known as the European white birch or weeping birch and is considered invasive in some states in the United States and parts of Canada. The tree can also be found in more temperate regions of Australia.
Armillaria mellea, commonly known as honey fungus, is an edible basidiomycete fungus in the genus Armillaria. It is a plant pathogen and part of a cryptic species complex of closely related and morphologically similar species. It causes Armillaria root rot in many plant species and produces mushrooms around the base of trees it has infected. The symptoms of infection appear in the crowns of infected trees as discoloured foliage, reduced growth, dieback of the branches and death. The mushrooms are edible but some people may be intolerant to them. This species is capable of producing light via bioluminescence in its mycelium.
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus Scolytus, namely the European elm bark beetle S. multistriatus and the large elm bark beetle S. scolytus, which like the American elm bark beetle Hylurgopinus rufipes, transmit Dutch elm disease fungi (Ophiostoma). The mountain pine beetle Dendroctonus ponderosae, southern pine beetle Dendroctonus frontalis, and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips Ips typographus. A tiny bark beetle, the coffee berry borer, Hypothenemus hampei is a major pest on coffee plantations around the world.
Oak wilt is a fungal disease caused by the organism Bretziella fagacearum that threatens Quercus spp. The disease is limited to the eastern half of the United States; first described in the 1940s in the Upper Mississippi River Valley. The pathogen penetrates xylem tissue, preventing water transport and causing disease symptoms. Symptoms generally consist of leaf discoloration, wilt, defoliation, and death. The disease is dispersed by insect vectors and to adjacent trees through underground root networks. However, human spread is the most consequential dispersal method. Moving firewood long distances can potentially transport diseases and invasive species.
Girdling, also called ring-barking, is the circumferential removal or injury of the bark of a branch or trunk of a woody plant. Girdling prevents the tree from sending nutrients from its foliage to its roots, resulting in the death of the tree over time, and can also prevent flow of nutrients in the other direction depending on how much of the xylem is removed. A branch completely girdled will fail and when the main trunk of a tree is girdled, the entire tree will die, if it cannot regrow from above to bridge the wound. Human practices of girdling include forestry, horticulture, and vandalism. Foresters use the practice of girdling to thin forests. Extensive cankers caused by certain fungi, bacteria or viruses can girdle a trunk or limb. Animals such as rodents will girdle trees by feeding on outer bark, often during winter under snow. Girdling can also be caused by herbivorous mammals feeding on plant bark and by birds and insects, both of which can effectively girdle a tree by boring rows of adjacent holes.
Birch bark or birchbark is the bark of several Eurasian and North American birch trees of the genus Betula.
In trees, heart rot is a fungal disease that causes the decay of wood at the center of the trunk and branches. Fungi enter the tree through wounds in the bark and decay the heartwood. The diseased heartwood softens, making trees structurally weaker and prone to breakage. Heart rot is a major factor in the economics of logging and the natural growth dynamic of many older forests. Heart rot is prevalent throughout the world affecting all hardwood trees and can be very difficult to prevent. A good indication of heart rot is the presence of mushrooms or fungus conks on the tree.
Diplodia tip blight, also known as Sphaeropsis blight, is a widespread disease affecting conifers caused by an opportunistic fungal pathogen, Diplodia sapinea. It is found in “both hemispheres between the latitudes 30° and 50° north and south". The diseases symptoms include: damping off and collar rot of seedlings, stem canker, root disease, and, most commonly, shoot blight. These symptoms have caused significant economic loss to nurseries and pine plantations. In a nursery in the north-central United States, losses of 35% have been reported. Shoot blight and eventual die back can cause a reduction of marketable volume in timber by 63%. Infection of terminal shoots can result in dead-top which significantly limits the usable length of the tree trunk. The presence of the pathogen in concert with severe weather conditions can lead to extreme loss. Following a severe hailstorm in South Africa, nearly 5,000 acres of pine plantation were infected with Diplodia tip blight. It was necessary to prematurely harvest large swaths of the plantations resulting in a loss of 45%. Areas that were not harvested prematurely still suffered an average timber loss of 11%.
Beech bark disease is a disease that causes mortality and defects in beech trees in the eastern United States, Canada and Europe. In North America, the disease occurs after extensive bark invasion by Xylococculus betulae and the beech scale insect, Cryptococcus fagisuga. Through a presently unknown mechanism, excessive feeding by this insect causes two different fungi to produce annual cankers on the bark of the tree. The continuous formation of lesions around the tree eventually girdles it, resulting in canopy death. In Europe, N. coccinea is the primary fungus causing the infection. Infection in European trees occurs in the same manner as it does in North American trees. Though the disease still appears in Europe, it is less serious today than it once was.
A branch collar is the "shoulder" between the branch and trunk of woody plants; the inflammation formed at the base of the branch is caused by annually overlapping trunk tissue. The shape of the branch collar is due to two separate growth patterns, initially the branch grows basipetally, followed by seasonal trunk growth which envelops the branch.
Nectria cinnabarina, also known as coral spot, is a plant pathogen that causes cankers on broadleaf trees. This disease is polycyclic and infects trees in the cool temperate regions of the Northern Hemisphere. N. cinnabarina is typically saprophytic, but will act as a weak parasite if presented with an opportunity via wounds in the tree or other stressors that weaken the tree's defense to the disease. A study published in 2011 showed that this complex consists of at least 4 distinct species. There are only a few ways to manage this disease with techniques such as sanitation and pruning away branches that have the cankers. N. cinnabarina is not as significant a problem as other Nectria spp., some of which are the most important pathogens to infect hardwood trees.
Erythricium salmonicolor is a species of fungus in the family Corticiaceae. Basidiocarps are effused, corticioid, smooth, and pinkish and grow on wood. The fungus is a commercially significant plant pathogen which has become a serious problem, especially in Brazil. Erythricium salmonicolor causes Pink Disease, most commonly in Citrus, although E. salmonicolor has a wide host range including rubber and cacao trees. Pink Disease causes branch and stem die-back due to canker formation. The cankers are recognizable by gum exudation and longitudinal splitting of the bark.
Phytophthora megakarya is an oomycete plant pathogen that causes black pod disease in cocoa trees in west and central Africa. This pathogen can cause detrimental loss of yield in the economically important cocoa industry, worth approximately $70 billion annually. It can damage any part of the tree, causing total yield losses which can easily reach 20-25%. A mixture of chemical and cultural controls, as well as choosing resistant plant varieties, are often necessary to control this pathogen.
Hymenochaete corrugata is a plant pathogen that causes glue crust in its hosts.
Bursaphelenchus xylophilus, commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the Pinus genus of coniferous trees and causes the disease pine wilt. While native to North America, it spread in the early 20th century to Japan and in the latter half of the century to other areas of Asia, including China, Taiwan, and Korea, as well as to Europe, including Portugal and Spain.
Sun scald is the freezing of bark following high temperatures in the winter season, resulting in permanent visible damage to bark. Fruits may also be damaged. In the northern hemisphere, it is also called southwest injury.
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees.
Phytobia betulae is a species of fly in the family Agromyzidae. It is native to Northern and Eastern Europe, being common in Scandinavia. Its larvae tunnel through the branches and trunk of birch trees, often leaving a dark stain in the timber but not adversely affecting the tree's growth.
References
- ↑ International Library of Technology. (1913). Apple Pests and Injuries. Vol. 124. Scranton, Pennsylvania: Scranton International Textbook. pp. 79–80. doi:10.5962/bhl.title.46116.
