|
High Forest (woodland)
A high forest is a type of forest originated from seed or from planted seedlings. In contrast to a low forest (also known as a coppice forest), a high forest usually consists of large, tall mature trees with a closed canopy. High forests can occur naturally or they can be created and maintained by human management. Trees in a high forest can be of one, a few or many species. A high forest can be even-aged or uneven-aged. Even-aged forests contain trees of one, or two successional age classes (generations). Uneven-aged forests have three or more age classes represented. High forests have relatively high genetic diversity compared with coppice forests, which develop from vegetative reproduction. A high forest can have one or more canopy layers. The understory of a high forest can be open (parklike, easy to see and walk through), or it can be dense. A high forest's understory can have high or low vegetation species diversity. See also * Coppicing * Ecological thinning *Old ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds ''in situ''. It does not include land that is predominantly under agricultural or urban use." Using this definition, '' Global Forest Resources Assessment 2020'' (FRA 2020) found that forests covered , or approximately 31 percent of the world's land area in 2020. Forests are the predominant terrestrial ecosystem of Earth, and are found around the globe. More than half of the world's forests are found in only five countries (Brazil, Canada, China, Russia, and the United States). The largest share of forests (45 percent) are in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coppicing
Coppicing is a traditional method of woodland management which exploits the capacity of many species of trees to put out new shoots from their stump or roots if cut down. In a coppiced wood, which is called a copse, young tree stems are repeatedly cut down to near ground level, resulting in a stool. New growth emerges, and after a number of years, the coppiced tree is harvested, and the cycle begins anew. Pollarding is a similar process carried out at a higher level on the tree in order to prevent grazing animals from eating new shoots. ''Daisugi'' (台杉, where ''sugi'' refers to Japanese cedar), is a similar Japanese technique. Many silviculture practices involve cutting and regrowth; coppicing has been of significance in many parts of lowland temperate Europe. The widespread and long-term practice of coppicing as a landscape-scale industry is something that remains of special importance in southern England. Many of the English language terms referenced in this article are pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Even-aged Timber Management
Even-aged timber management is a group of forest management practices employed to achieve a nearly coeval cohort group of forest trees. The practice of even-aged management is often pursued to minimize costs to loggers. In some cases, the practices of even aged timber management are frequently implicated in biodiversity loss and other ecological damage. Even-aged timber management can also be beneficial to restoring natural native species succession. Process The first step in even aged timber management is to select a suitable stand for harvest. Trees must be of merchantable size, a desirable species, and in an area accessible to harvesting equipment. Once selected, the stand is harvested (usually using feller-bunchers, skidders, and processors). Merchantable trees (trees with boles large enough to be sold to a mill) are harvested and processed whereas unmerchantable trees (trees that are too small or of an undesirable species) are either crushed by machinery or cut to make eq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of Genetics, genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vegetative Reproduction
Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or specialized reproductive structures, which are sometimes called vegetative propagules. Many plants naturally reproduce this way, but it can also be induced artificially. Horticulturists have developed asexual propagation techniques that use vegetative propagules to replicate plants. Success rates and difficulty of propagation vary greatly. Monocotyledons typically lack a vascular cambium, making them more challenging to propagate. Background Plant propagation is the process of plant reproduction of a species or cultivar, and it can be sexual or asexual. It can happen through the use of vegetative parts of the plants, such as leaves, stems, and roots to produce new plants or through growth from specialized vegetative plant parts. Wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canopy (biology)
In biology, the canopy is the aboveground portion of a plant community, plant cropping or crop, formed by the collection of individual Crown (botany), plant crowns. In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms (epiphytes, lianas, Arboreal, arboreal animals, etc.). The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree or group of trees. Shade trees normally have a dense canopy that blocks light from lower growing plants. Observation Early observations of canopies were made from the ground using binoculars or by examining fallen material. Researchers would sometimes erroneously rely on extrapolation by using more reachable samples taken from the understory. In some cases, they would use unc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Understory
In forestry and ecology, understory (American English), or understorey (Commonwealth English The use of the English language in current and former member countries of the Commonwealth of Nations was largely inherited from British colonisation, with some exceptions. English serves as the medium of inter-Commonwealth relations. Many ...), 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 broadleaf and mixed forest, temperate deciduous forests, many understory plants start into growth earlier in the year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Diversity
Species diversity is the number of different species that are represented in a given community (a dataset). The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundance as that observed in the dataset of interest (where all species may not be equally abundant). Meanings of species diversity may include species richness, taxonomic or phylogenetic diversity, and/or species evenness. Species richness is a simple count of species. Taxonomic or phylogenetic diversity is the genetic relationship between different groups of species. Species evenness quantifies how equal the abundances of the species are.Hill, M. O. (1973) Diversity and evenness: a unifying notation and its consequences. Ecology, 54, 427–432Tuomisto, H. (2010) A diversity of beta diversities: straightening up a concept gone awry. Part 1. Defining beta diversity as a function of alpha and gamma diversity. Ecography, 33, 2-22. Tuomisto, H. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old-growth Forest
An old-growth forestalso termed primary forest, virgin forest, late seral forest, primeval forest, or first-growth forestis a forest that has attained great age without significant disturbance, and thereby exhibits unique ecological features, and might be classified as a climax community. The Food and Agriculture Organization of the United Nations defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. More than one-third (34 percent) of the world's forests are primary forests. Old-growth features include diverse tree-related structures that provide diverse wildlife habitat that increases the biodiversity of the forested ecosystem. Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollarding
Pollarding is a pruning system involving the removal of the upper branches of a tree, which promotes the growth of a dense head of foliage and branches. In ancient Rome, Propertius mentioned pollarding during the 1st century BCE. The practice occurred commonly in Europe since medieval times, and takes place today in urban areas worldwide, primarily to maintain trees at a determined height or to place new shoots out of the reach of grazing animals. Traditionally, people pollarded trees for one of two reasons: for fodder to feed livestock or for wood. Fodder pollards produced "pollard hay" for livestock feed; they were pruned at intervals of two to six years so their leafy material would be most abundant. Wood pollards were pruned at longer intervals of eight to fifteen years, a pruning cycle tending to produce upright poles favored for fencing and boat construction. Supple young willow or hazel branches may be harvested as material for weaving baskets, fences, and garden constr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silviculture
Silviculture is the practice of controlling the growth, composition/structure, and quality of forests to meet values and needs, specifically timber production. The name comes from the Latin ('forest') and ('growing'). The study of forests and woods is termed '' silvology''. Silviculture also focuses on making sure that the treatment(s) of forest stands are used to conserve and improve their productivity. Generally, silviculture is the science and art of growing and cultivating forest crops, based on a knowledge of silvics (the study of the life-history and general characteristics of forest trees and stands, with particular reference to local/regional factors). The focus of silviculture is the control, establishment and management of forest stands. The distinction between forestry and silviculture is that silviculture is applied at the stand-level, while forestry is a broader concept. Adaptive management is common in silviculture, while forestry can include natural/conserved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
