Tree microhabitat
A “microhabitat” ( ancient Greek μικρός mikrós , German “small, narrow” , Latin habitat- “[he, she, it] inhabits” ) is a habitat with a small spatial extent. Tree microhabitats thus represent delimitable habitats in, on or on trees.
The term tree microhabitats covers changes in the bark, trunk or crown structure of living and dead trees. These can weaken the tree's natural defense reactions and, for example, colonization by various wood fungi , microorganisms or xylobiont insect species can occur. Many birds and mammals also use or create such special structures as breeding grounds or retreats. The additional colonization of different organisms bound to tree microhabitats can enormously increase the diversity of species and therefore plays an increasingly central role, both in biodiversity research and in the goal of maintaining or increasing biodiversity .
Trees that have microhabitat structures or have the potential to do so are, however, often removed during thinning in a commercial forest, as the wood structures change and therefore future use does not appear sensible from an economic perspective.
Tree microhabitats can have already decomposed wood or provide a habitat without wood decomposition. The probability of a tree developing microhabitats increases with increasing dimension, age, tree species and declining vitality . In general, one can say that a larger tree diameter, due to a larger life span, crown deadwood, loose bark and cracks promotes biodiversity. In some studies it has been shown that in Central Europe, deciduous tree stands or mixed stands have a greater number and diversity of microhabitats than pure conifer stands. Due to forest management, the density of tree microhabitats generally decreases, but some tree microhabitats, such as bark injuries, can also be promoted by wood harvesting measures.
Tree microhabitats can be grouped according to different shapes:
| Tree microhabitat shape | Examples |
| Tree hollows | Woodpecker holes, sludge holes, insect-feeding holes |
| Trunk injuries and exposed splint | Detached bark, trunk or branch breaks |
| Crown deadwood | Dead branches in the treetop |
| Growths | Measles bulbs, crabs, mistletoe |
| Mushroom fruit bodies | Mushroom consoles or fruiting bodies of annual mushrooms |
| Epiphytic structures | Nests, overlying plants and lichens |
| Outflows | Juice or resin flow |
Tree hollows
Tree hollows come in a wide variety of sizes and shapes. In the caves Mulmkörper develop and bags, nests, populated with mushrooms indoors and rugged gear systems and deadwood zones . Depending on the tree cavity, there are differences in the type of fungus, the stage of wood decomposition and moisture penetration, which can lead to insects differing in their species. Large caves develop over decades and are used by birds , smaller mammals and amphibians because of the large food supply and the stable microclimate. A prominent colonist of sludge bodies is the hermit . Caves can be built by cave-building species such as the woodpecker, and these in turn can be colonized by secondary users such as bees and hornets .
Characteristic species: wildcat ( Felis silvestris ), dormouse ( Glis glis ) and many native woodpecker species
Woodpecker and branch caves
A woodpecker den is a breeding cave built by a woodpecker on a living or dead tree. Woodpecker caves can be found in the upper crown area ( small woodpecker ), on dead branches, high stumps or in trunk areas populated with fungi. The woodpecker caves not only provide a habitat for the woodpecker, but also for a large number of other organisms such as insects. However, most insect species do not colonize the cave for a few years after the wood decomposition has progressed. If more than two woodpecker holes in max. 2 m above each other on the trunk, this is called the cave floor. Possible reasons for the formation of floors are: construction of separate sleeping and breeding caves by black woodpeckers or creation of new replacement entrances due to advanced decomposition of the previous entrances. Other variants: severe trunk or bark injuries but also decomposition by fungi with subsequent cavity formation. Cave floors are potential preliminary stages of a large cave. Secondary inhabitants of woodpecker holes are u. a. Stock dove ( Columba oenas ) or pygmy owl ( Glaucidium passerinum ).
Characteristic species: blue longhorn beetle ( Ischnomera cyanea and Ischnomera caerulea ), tawny owl ( Strix aluco ), gold-fur scabbard ( Pholiota cerifera ).
Knot cavities are septic caverns created by breaking off branches.
Characteristic species: large gold beetle ( Protaetia aeruginosa ), black woodpecker ( Dryocopus martius ), woodpecker-hole schillerporling ( Inonotus niduspici ), common rose beetle ( Cetonia aurata ), great crested tit ( Lophophanes cristatus )
Hollowed out trunks
Hollowed out trunks are long, tubular caves in the trunk with stable microclimatic conditions. Hollowed out trunks often have a thickened trunk base due to lignin degradation with subsequent wood softening. The fungus can work its way up the trunk or down to the ground.
Characteristic species: blood-necked click beetle ( Ischnodes sanguinicollis ), crusted mushroom ( Hypoxylon deustum ), tawny owl ( Stix aluco ) and dormouse ( Muscardinus avellanarius )
Caves with ragged bodies
Caves with sludge bodies are tree hollows that contain wood sludge with an amount of at least 8 dm ^ 3. For decades, different types of fungi attack areas on the tree that are important for survival in a much less aggressive way. Cambium and sapwood in particular are attacked in this way and, as a result, gnawed and reduced in size by lignicolous insects. Initial points are open fractures, crevices, cracks and not surrounded by the bark , as well as grazed areas or smaller cavities. Wood ants form their colonies in this so-called gnawing meal and break it up even more (primary wood mulm). Additional organic material is brought in by small mammals, birds and insects such as bees or hornets, which leads to an increased supply of nutrients.
Characteristic species: Ocher-colored hydrabasidia ( Uthatobasidium ochraceum ), violet- blue root- necked snapback beetle ( Limoniscus violaceus ), dormouse ( Muscardinus avellanarius )
Insect holes
Insect holes are galleries and boreholes created by insects, such as those created by bark beetles . These preferentially attack weakened and dying trees and lay their eggs in the bark (bark breeders) or in the sapwood (wood breeders). This is accompanied by the easily recognizable feeding and breeding channels. A well-known example is the hero buck ( Cerambyx cerdo ), one of the largest beetles in Central Europe. The Heldbock colonizes only very old oaks that are in a light, warm location.
Indentations
Water pots ( dendrotelme ): bulges or hollows that open upwards with the possibility of water accumulation. The depressions are often caused by injuries. Typical are branched overground roots trunk base, closely upward, to each other branches in branch forks, over flashes at crotches, Stammverwachsungen and avulsion of branches. The water level in the water pots depends on precipitation and evaporation. With permanent accumulation, a dendrotelm is an ideal habitat and reproduction site for amphibians such. B. the tree frog ( Hyla arborea ). Fungal colonization in rotten areas with periodic drying out. Water pots house a few but very specialized insect species.
Characteristic species: Marsh fever beetle ( Prionocyphon serricornes ), bumblebee hover fly ( Mallota fuciformis )
Further indentations: woodpecker feeding holes, bark-covered indentations on the trunk
Trunk injuries and exposed splint
Lightning gutters
A lightning gutter is a gutter on a tree trunk that is caused by a lightning strike. The sapwood now exposed can be colonized by wood-degrading fungi. The resulting gaps can be used as hiding places.
Characteristic species: black beetle ( Corticeus unicolor ), pipistrelle bat ( Pipistrellus pipistrellus ), hedgehog goatee ( Hericium erinaceum )
Cracks and crevices
Strong and, over time, damaging stresses in the tree can lead to expanded cracking in trunk and branches. This is usually caused by an uneven distribution of the crown load, twisting growth, the effects of frost or extreme forces caused by strong winds. In the further course, cracks and crevices can develop into sludge caves due to the settlement of fungi. Columns are also used as hiding places.
Characteristic species: slime river beetle ( Nosodendron fasciculare ), treecreeper ( Certhia brachydactyla ), bump-headed ram ( Rhamnusium bicolor ), great linden beetle ( Scintillatrix rutalins )
Digs
Relatively large areas of imperfection in the bark on the trunk or base of the trunk are called scrapes. These are caused by neighboring trees falling over, parts of the crown breaking off or damage caused by game, but also by timber harvesting measures. Possible consequences are fungal and insect infestation due to a missing bark.
Characteristic species: Beetle comb beetle ( Isorhipis melasoides ), gold skin scabbard ( Pholiota cerifera ), rust-haired buck ( Anisarthron barbipes )
Crown and partial crown fractures
In the case of a crown fracture, more than half of the crown has broken off, in the case of a partial crown fracture, less than half of the crown has broken off, but at least one major branch of the 1st order must be affected. The demolition leads very quickly to deep injuries to the trunk, the result is a rapid settlement of mushroom species with the result of a rapidly growing cave up to a large cave.
Characteristic species: Mesosa curculionoides , yellow-scaly click beetle ( Lacon quercus ), red-necked longhorn beetle ( Ischnomera sanguinicollis ), common oyster mushroom ( Pleurotus ostreatus ) , corn goat ( Megopis scabricornis )
Broken trunk
In the event of a trunk break, the tree crown breaks off completely, but branches can develop into a replacement or secondary crown while the trunk area has almost completely died off.
Characteristic species: blood-necked longhorn beetle ( Ischnomera sanguinicollis ), matt black click beetle ( Megapenthes lugens ), miniature flycatcher ( Ficedula parva )
Zwiesel abort
Complete demolition of a Zwiesel trunk at the base of the Zwiesels leads to sapwood and heartwood being exposed. This is the preliminary stage for wood, sludge pockets and hollows / hollows that have been populated with mushrooms.
Characteristic species: Lung oyster mushroom ( Pleurotus pulmonarius ), blood-red skin head ( Cortinarius sanguineus ), beetle beetle ( Tillus elongatus )
Bark pockets
Detached pieces of bark on dying or already dead tree areas are bark pockets. Use by / protection for insects or breeding place / hiding place for birds e.g. B. treecreeper and some bat species such. B. Pug Bat ( Barbastella barbastellus ). Smooth transition between cattle pockets with or without sludge .
Mulm pockets are bark pockets with accumulated gnawing dust, nesting material, wooden mulm and small pieces of wood, often mixed with nutrient-rich organic material (remains of prey or arthropod droppings). Because of the richness of nutrients, fungal attack often takes place, e.g. B. by inks and crumbs.
Characteristic species: billy buck ( Cerambyx cerdo ), fur beetle ( Trinodes hirtus ), pug bat ( Barbastella barbastellus ), dormouse ( Glis glis )
Crown deadwood
Dead branches in the lower crown area are caused, among other things, by shading, dead crown tips by drought stress and large branches breaking off by mechanical impact. By opening the canopy, mainly light- and heat-loving insect species benefit. The dead wood in living trees can still be partially supplied by transpiration and assimilation currents and connected with fungal mycelia .
Characteristic species: Fir goatee ( Hericium flagellum )
Growths
Cancer : uneven bulging on the branch and trunk. Triggers are bacteria or fungi in the bark, e.g. B. Ashes of the genus Nectria. The result is an attempted wound closure in the areas of dead parts of the bark. This provides a habitat for fungi and arthropods and is therefore a suitable food source for many bird species.
Measles bulbs : Often triggered by the microorganism Agrobacterium tumefaciens , forces the host to grow above average. The cracks and crevices provide a habitat for fungi and arthropods. Over time, a large cave can develop.
Characteristic species: oak glass winged ( Synanthdon conopiformis ), wasp glass winged ( Synanthdon vespiformis ), pine marten ( Martes martes ), middle woodpecker ( Dendrocopos medius )
Witch's broom : Permanent formation of many short branches as a result of a fungal attack.
Water tear : sprout that sprouts out of a sleeping bud in the area of the trunk after an injury or after a change in light conditions .
Mushroom fruit bodies
A distinction must be made between perennial (perennial porlings), short-lived mushroom fruit bodies (annual porlings, stand mushrooms , large hose mushrooms) and slime molds . Tinder and tree sponges ( Fomes fomentarius , Fomitopsis pinicola ) are among other representatives the most common lignicole fungi that can develop a tree microhabitat with their fruiting bodies.
Tinder fungi
The tinder sponge can only be found in living, by natural aging or by z. B. drought stress or mechanical injuries of already damaged trees settle. The fruiting bodies provide habitat for up to 600 different species in different stages of decomposition.
Characteristic species: Olive-colored wooden cup ( Catinella olivacea ), notched-necked sponge beetle ( Bolitophagus reticulatus ), small woodpecker ( Dendrocopos minor ), common Krausblattmoos ( Ulota crispa )
Sponge trees
Tree sponges are trees with the fruiting bodies of the red rimmed tree sponge. Growth takes place on deciduous and coniferous trees that are still alive but already weakened or even dead.
Characteristic species: butterfly tramete ( Trametes versicolor ) , notched-necked mold beetle ( Pteryngium crenatum ), real moth ( Triaxomera fulvimitrella )
Other species: Tooth-necked tree sponge black beetle ( Eledonoprius armatus ), blue-winged rotterwood beetle ( Triplax aenea ), black woodpecker ( Dryocopus martius )
Epiphytic, epixylic and parasitic structures
Climbing plant trees or lichen and moss cushion training
Minimum height and coverage of climbing plants: 3 m and 2 m². The interweaving of the tendrils serves as a climbing aid but also as a resting place / resting place for z. B. wildcats, at the same time it serves as a breeding and sleeping place for birds. The plant cover stabilizes a moist microclimate ideal for a species-rich fungal flora. Moss stores moisture for a long time and leads to the initial formation of humus . Together with the lichen growth, it houses a large number of different types of fungus.
Characteristic species are: blue bark helmetling ( Mycena pseudicorticola ), pine marten ( Martes martes ), wild cat, wren ( Troglodytes troglodytes )
Eyrie trees
Eyries (large nests) are created by some species of birds such as sea eagles, ospreys and spotted eagles, hawks, sparrowhawks, herons and storks. Requirements are large crowns, good approach aisles and suitable, strong branch structures. Some bird species use already existing clumps, such as B. the long-eared owl ( Asio otus ), other species use smaller clumps of other birds as a basis to build their own eyrie on it, for example the common buzzard ( Buteo buteo ).
Characteristic species that colonize or use eyries: Stutz beetles ( Histeridae ), Raven- winged beetles ( Haploglossa gentilis )
Micro soils in the bark and crown
Micro-soils are humus forms in the bark and crown that are formed by decomposition.
Outflows
Sap flow: Clearly visible, considerable flow of sap, which occurs predominantly in deciduous tree species. The flow of sap is a defense reaction of the tree as a result of minor injuries or fungal infections and at the same time an important food source for many species of beetles. The sugar-rich sap flow points on the oak also serve as mating sites for the stag beetle ( Lucanus cervus ).
Resin flow: After injuries, for example through broken branches, damage to the bark from felling or insect infestation, conifers try to close the wound with resin flow and thus prevent the entry of harmful organisms.
Characteristic species: golden beetle ( Protaetia spp . )
Application and practical significance
In comparison to individual species, tree microhabitats are structural elements that are true to their location and can be easily identified. Through the possibility of linking tree microhabitats with associated species that may be endangered, tree microhabitats can be assigned an indicator function. The aim of classifying and describing tree microhabitats (e.g. in the form of a detailed catalog) is to map them in a standardized, comprehensive and repeatable manner. Based on the diversity and number of tree microhabitats, conclusions can be drawn about possible species occurrences.
Detailed descriptions and illustrations can be found in a tree microhabitat catalog for guidance. The recording forms the settlement potential for microhabitat-dependent species such as B. Certain species of birds, insects and fungi instead of actively searching for these species. However, whether these species actually colonize the structures found and whether other species are just as important or colonize these structures remains unclear without special studies.
Marteloscope
A marteloscope is a concept for silvicultural education and training. It serves as a demonstration and training area for the consideration of nature conservation aspects in forest management. Marteloscopes are also a useful tool to illustrate tree microhabitats and their importance or function in the forest ecosystem. The focus is on the exchange of experience and silvicultural training. Marteloscopes are demarcated areas in a real tree population. With the help of software, different treatment scenarios can be displayed. The primary goals are an objective view and discussion of simulated silvicultural interventions as well as a representation of the resulting ecological and economic effects. To ensure this, the entire real tree population is mapped and numbered in advance. Individual trees are evaluated according to ecological (recording according to a set standard of existing and potential tree microhabitats according to criteria in the catalog and according to rarity or duration of emergence) and economic (volume calculation, current and regional price lists and future quality assessment) criteria.
literature
- Möller et al .: Der Fauna-Käferführer1-Käfer in and on the forest. Fauna Verlag, Nottuln 2006.
- G. Möller: Structure and substrate binding of wood-dwelling insects, focus on Coleoptera beetles. Dissertation Free University of Berlin 2009.
- UNESCO- United Nations Educational, Scientific and Cultural Organization, World Heritage Conservation: Primeval Beech Forests of the Carpathians and Ancient Beech Forests of Germany. Application dossier, 2011 whc.unesco.org .
- S. Winter: Determination of structural indicators to estimate the influence of forest management on the biocenoses of lowland beech forests. Dissertation, Technical University of Dresden 2005.
Individual evidence
- ↑ Stefan Nehring, Ute Albrecht: Biotop, Habitat, Microhabitat - A contribution to the discussion on the definition of the term. (PDF) Retrieved November 14, 2018 .
- ↑ Susanne Winter: Microhabitats and phase mapping as the core of the biodiversity assessment in the forest. (PDF) Retrieved November 14, 2018 .
- ↑ Which factors influence the occurrence and density of tree microhabitats in Mediterranean oak forests? In: Forest Ecology and Management . tape 295 , May 1, 2013, ISSN 0378-1127 , p. 118–125 , doi : 10.1016 / j.foreco.2013.01.009 ( sciencedirect.com [accessed November 14, 2018]).
- ^ Asbeck et al .: Predicting abundance and diversity of tree-related microhabitats in Central European montane forests from common forest attributes. Retrieved November 14, 2018 .
- ↑ Großmann et al .: Predictors of Microhabitat Frequency and Diversity in. Retrieved November 14, 2018 .
- ↑ Larrieu et al .: Tree related microhabitats in temperate and Mediterranien European forests: A hierarchical typology for inventory standardization. Retrieved November 14, 2018 .
- ↑ a b c d e f g h i j k l m n o p q r s t u v Winter et al .: Praxishandbuch- Naturschutz im Buchenwald . Ed .: Ministry for Rural Development, Environment and Agriculture Brandenburg, 2015. Ministry for Rural Development, Environment and Agriculture Brandenburg, Schorfheide-Chorin 2015, ISBN 978-3-00-051827-0 .
- ↑ Fritz Schwerdtfeger: The forest diseases . Textbook of forest pathology and forest protection . ISBN 3-490-09116-7 .
- ↑ Schütt et al .: Lexicon of tree and shrub species . Hamburg 2002, ISBN 3-933203-53-8 .
- ↑ a b Integrate + Marteloskope, calibration of silvicultural decisions. (PDF) Retrieved November 14, 2018 .
- ↑ INFORMAR-Integrated Forest Management Learning Architecture. Retrieved November 15, 2018 .