A B C D E F G H I L M N O P R S T U V W Y 



Adaptation – morphological behavior of species or population ensuring normal bioactivity of the organism under certain environmental conditions.

Afforestation – establishment of forest areas with seedlings and planting stocks grown in the nursery. It is performed by relevant machinery or by hand (spade) based on the planting stock, relief and condition of the soil.

Age class – Tree age calculation indicator. It is used to determine the age of the forest stand. Age class is defined by the time period, tree growth rate and climatic conditions. In the moderate climate zone one age class is equal to 20 calendar years for stiff-leaved and mixed wood stands, 10 years for fast-growing tree varieties and 5 years for bush varieties. In the tropical zone one age class is equal to 5 years, and in the subtropical zone it is equal to 10 years.

Agro-forestry reclamation zoning – division of land into reforestation areas, based on forest-growing conditions. Division is based on soil-climatic, hydrological, geological, topographic factors and agricultural orientation. Agro-forestry reclamation zoning is applied in the planning of agro-forestation activities, selection of tree and shrub species, establishment of forest belts and planning of agro-technical activities for their development.

Annual rings – emerge due to the division of cells, which form wood in their inward vegetation process, and a layer of phloem – in case of outward vegetation. At the beginning of vegetation relatively big cells appear in the wood, and small cells appear in summer. Light and dark colors observed in wood transaction make the annual growth rings visible.

Anthropogenic Factors -human-induced environmental changes. These changes can be direct –forest cover destruction, and indirect, which can be caused by the changes in the landscape, climate, physical property and composition of air, soil, etc. Environmental pollution by domestic and industrial wastes results in ecological misbalance, disintegration (biocoenosis) of the coexistence of organisms. Humans have created a new environment for crops and animals (agrocoenosis) by improving soil fertility.



Beech tree – beech family deciduous, single-stem tree of up to 45-50 m height and 1-2 m trunk length. One beech variety grows in Armenia – Eastern Beech. The leaves are ellipse-shaped and dark green. Photic leaves are coriaceous, lanate on the back side. Foliage is well-composed, trunk is smooth and grey. Flowers are diclinous. Male flowerages hang on long tendrils. Female flowerages are composed of binate flowers and are arranged in the crown of the branches. Blooming stage overlaps with leaf-formation stage. Fruit is the triquetrous acorn with thin, hard shell, and it contains up to 50 per cent fat. Roots are shallow. Duration of life is up to 250 years. They also reproduce by coppice shoots at young age (40-50 year-old). It is a shadow-tolerant, hydrophilic, relatively cold-resistant tree variety, has high soil fertility requirements. It grows in the Caucasus, Transcaucasia, at the elevation of up to 2200 m. It grows in the Northern regions of Armenia on 91,2 thousand hectares of area. High efficiency forest stands grow on the northern slopes of the mountains, on the elevation of 1200-1600 m. It forms uniform and sometimes mixed forest stands together with linden, sharp-leaf maple and forest cherry. It forms complex forest stands on the southern slopes of the mountains together with hornbeam.

Beech wood –homogeneous beech stand or a stand where beech trees prevail. It is common to the northern forest areas of Armenia, where it forms highly efficient forest stands at the elevation of 1200-1600 m.

Biological methods of pest control of forests – Integrated use of the materials produced by the organisms or during their life cycle for pest and disease control.

Biomass – total mass of an individual, certain variety or a group and general coexistence in a unit area calculated by weight or other indicators. Plant biomass is called phytomass and animal biomass is called zoomass.

Board – 13-100 mm-thick sawn timber. If the thickness of the board is below 32 cm, it is considered to be thin, if it is over 32 mm, it is considered thick.

Broad-leaved deciduous forests – Forests formed of fine-leaved or broad-leaved tree species. Tropical rainforests, seasonal evergreen and seasonal deciduous forests, subtropical stiff-leaved and wintergreen (savannah) forests are included in this group.  Species composition of broad-leaved deciduous forests depends on the climatic conditions.

Burnt-out forest – part of the burnt forest, where there are partially burnt, drying, standing and fallen trees.



Callipers –device for measuring the thickness of a growing tree. Vernier caliper type wooden or soft aluminum ruler is used for that purpose. Capillers can also be used to measure the height of trees.

Classification of forest fires – forest fires are practically classified into 3 types – lower, or surface, upper or crown and ground fire. Sometimes the fourth type of fire is also distinguished – trunk fire. In addition to the above mentioned types there are also mixed fires, when fires of the second or third types come together, and transitional fires, when the fire of one type changes into a fire of another. Based on intensity criterion, surface fires can be weak, mild and intensive. Based on the nature of expansion, surface fires are divided into instantaneous, which moves very fast burning the live cover, upper layer of the ground cover, partially young trees and underwood, and steady, which propagates slowly, comprising the entire ground cover and tree trunk bases. Crown fires are divided into storm fires, which quickly pass over tree crowns, burning the branches; and extensive fires – when the fire is steadier and covers the entire foliage. Ground fires can be deep-ground and surface-ground (typical to turf soils).

Classification of trees by Kraft – is defined by the indicator of the tree growth rate in the forest stand. Five classes are identified: First class includes overmature trees, the foliage of which stands out of the general foliage of the forest stand and dominates over it. Second class are trees that form the main foliage of the forest stand. Third class – trees included in the main foliage of the forest stand by their height, but their crown looks depressed. Trees belonging to classes 1-3 form the main foliage of the forest. The height of trees of the forth social class reaches the main foliage, and they look suppressed. The trees of the fifth social class are under the main foliage, and are sometimes semidry. The number of the trees of certain classes depends on the composition and age of the forest stand. The ratio of trees of different classes in the general forest stock is as follows: first class in the uniform forest stand of pine – 12%, oak – 11-27%; second and third classes are 50-60% and 48-71% respectively. Trees belonging to other classes have a minor share in the general stock.

Classification of trees by shadow tolerance – Trees can be shadow tolerant, heliophytic, and medium-heliophytic. The need for light is a morphological property of the varieties, which affects the formation of foliage, leaves, bark and other organs. Regardless of the level of the need for sun, the young stock of all the tree varieties has certain shadow tolerance. Along with the growth, the need for the light increases, and at polewood age tree develops the need for light typical of the given species.

Classification of trees by their thermophilic level – they are classified as follows- thermophil, cold resistant, average cold resistant and medium-thermophil.

Crown fire – during which the crown of the wood – foliage burns. It may be caused by ground fires due to strong winds. Propagation speed reaches to 15-20 km/hour.



Dead Soil Cover – leaves, branches, bark, fruits and other plant residues fallen in the forest during a year. Tree waste participates in the formation of forest floor and the soil itself. A great amount of organic matter penetrates into the soil annually. The amount of dead soil cover and organic matter penetrating in the soil is based on the composition, age and integrity of the forest stand. The lowest amount of dead soil cover is in the coniferous forests – 1,5 – 3 tones, the highest amount is in the broad-leaved forest stands – 3,5-4,5 t.

Dead soil covering – when vegetation is missing under the foliage and soil is covered with forest mat.

Deciduous trees bloom along with the opening of the leaves. They reproduce by seeds and coppice shoots. Five (5) oak tree varieties occur in the forests of Armenia – Caucasian Oak (Q. macranthera), Georgian Oak (Q. iberica), Araxian Oak (Q. araxina), Long-stalk Oak (Q. longipes) and Golden Oak (Quercus hypochrysa), the first three varieties are principal forest formation species. Oak stands in Armenia cover approximately 116, 000 ha area. Caucasian Oak– is common in all the forest areas of Armenia; it grows at elevations ranging from 1200-1400 m to 2400-2600 m. It is heliophitic, hydrophilic, cold-resistant, has particular soil requirements. Georgian Oak – grows in northern area of Armenia and in Zangezur at the elevations of 550 m to 1200-1400 m. It is heliophytic, of medium drought resistance, thermopile, prefers nutrient-rich soil. Araxian Oak – is common in the regions of Meghri and Kapan, in the lower forest belt, at the elevations below 900 m. It is thermophilic, heliophitic, drought-resistant, doesn’t have high soil requirements. Long-stalk Oak – individual trees or small groups are identified on the banks of the rivers Debed, Hakhum, Aghstev, Voghji, at the elevation of up to 1000 m. It is thermophilic, hydrophilic, has high soil requirements. Golden Oak – grows in the northern area of Armenia in Georgian oak forest stands.

Density of forest stand – number of trees and bushes per hectare of forest stand.  The following types of density are identified – primary planting (seeding) density and density of plantation. Optimal primary density of the plantation is based on the growth energy and natural-climatic factors of the transplanted (sown) species. The trees should be planted relatively densely if conditions are unfavourable. After the closure of the tree crowns, density of the plantation should be is regulated by sanitary cuttings.

“Drunk” forest –forest with crooked, recumbent trees, trees with oblique trunk, which generally grow on moving grounds, areas of permanent landslide and snowslide.



Economic age – is based on the age and growth factors of the tree. The growth of the annual rings decreases drastically in the old trees, as well as in young trees growing in bad conditions (the rate of transversal growth decreases). Economic age of the aforementioned trees is generally calculated in addition to the absolute age, by the following formula. –

Elite tree –  best tree, meeting one or several criteria, that is selected for seed-breading and selection purposes. If the selection is made based on the growth rate, diameter of the select tree should be 30 per cent, and height – 10 per cent more of the average tree of the given species.

Even-aged Forest – forest stand, where all the trees belong to the same age class. Absolute even-aged stands are artificial stands, and only at the young or medium age. Absolute even-aged trees are rarely detected in natural forests, and at young age only.



Fire hazard classification – Based on climatic conditions, forests are classified by fire-safety criteria, which enables to prevent and extinguish the fire. Four fire hazard classes are identified: 1) extremely high fire hazard – may be observed in warm, dry climatic conditions with average air temperature above 20˚ and relative humidity of air below 40%, 2) high fire hazard – areas, where dry climate prevails, and precipitations are occasional and light, relative humidity of air is 40-60 %, 3) slight fire hazard – rains are frequent, relative humidity of air is 60-80%, ground cover is moist. 4) fire-safe – long-lasting rains, relative humidity of air is above 80%.

Fire line – Forest area that is cleaned from flammable materials and thoroughly tilled to prevent forest fires.

Forest age – forest age is identified by age classes. Based on the conditions of growth and rate of growth of the given species, a class is 5 calendar years in the tropical zone, and 10-20 years in the temperate zone. Age class of the trees in northern latitude is often accepted 40 years, regardless of the species. Forest is even-aged if it is formed of trees of the same age group.  It is multiple-aged if the forest stand is formed of trees of more than two age groups. Artificial forest plantations, as well as trees of coppice shoot origin are even- aged. The term “forest age stage” is also used – young (wand), medium age, maturing, mature, over-mature.

Forest and Climate – Forest and Climate closely interact. Climate determines the type, composition and development of the plant cover. Since forests occupy enormous space, they have a substantial impact on meteorological elements creating microclimate typical of forests. Impact of Climate on the forest – in northern latitudes forest vegetation grows up to 10˚  isotherm, which is conditionally accepted as the northern border of forest, above which is tundra forest belt. Coniferous forests stretch out below 10˚ isotherm from west to east with forests composed of birch, oak, rowan and other broad-leaf deciduous tree species. Northern border of propagation of tree plants overlaps with daily average isoline of above 50, which is conditionally accepted as the start of vegetation. For example, northern border of larch propagation passes through the isoline, where the number of days with temperature above 5˚is 200, it is 150 days for tillet, and 210 days for beech. Volume of precipitations also has a great impact on vegetation reproduction. In the northern part of Russia, from west to east and south east, precipitations decrease particularly in the summertime whereas the temperature increases. This affects the composition, type and qualities of the forest.

Forest compartment – certain area of forest demarcated by pathways, roads or by natural borders (river, lake, mountain chain, etc.). Forest may be divided into compartments in a natural way, when it is demarcated by natural borders (forest compartment is shapeless), mixed, when one of its borders is natural, the other is artificial, and artificial when forest compartment is demarked by forest pathways.

Forest crop plantations – Establishment of forest plantations is one of main objectives of forestry. Forest plantations are artificially established plantations, by means of sowing or transplanting, for the purpose of forest rehabilitation, expansion of forest cover and reforestation, where no crown closure has yet occurred  and where forest management activities are performed (ploughing, weeding, etc.). Natural forest rehabilitation often requires small volume cuttings, when for some reason or another it becomes impossible to ensure seed reproduction, or unwanted varietal changes occur, it becomes necessary to perform silvicultural activities. Establishment of a successful forest plantation depends on accurate and timely agro-technical activities in addition to proper selection and distribution of tree species. Forest plantations become common practice when natural regeneration is missing, and partial, when natural regeneration is insufficient or does not occur with the primary species. Selection of primary species in forest plantations is based on the forest growth conditions- mainly soil productivity, eco-biological features of the species, and purposiveness of the established plantation. Based on forest growth conditions and growth rate of the species, 5-12 year old joined forest cultures are transplanted in the forest cover area.

Forest Density – one of the important forest assessment indicators, which used for the determination of the condition of forest stand and its resources, as well as for the planning of forest management activities. Forest integrity is determined by the sum of trunk surfaces on the level of 1, 3 meters (forest assessment integrity) or by the level of the tree crown closure (forestation integrity).  Forest assessment and forestation integrity correlation is not constant; it may vary due to the species, age and conditions of the tree. Two types of integrity are identified – absolute and relative. Absolute integrity is expressed by the sum of tree trunk surfaces per hectare or by the sum of total tree foliages (m²). Relative integrity is expressed by the tenth part of the total (0,9,0,7,0,8  etc.) ,where  complete crown closure is considered as one. In complex and mixed forest stands integrity is determined separately for different layers and species.

Forest district – regional industrial unit of Forestry enterprise where the following activities are implemented –1) forest marking (sealing), and release of timber to timber marketers and people, 2) control over the relevant implementation of rules and regulations for timber and non-timber forest use, 3) forest conservation and protection, 4) forest management activities (reforestation, care, afforestation, etc.), 5) sanitary logging. Forester is responsible for the implementation of forest management activities in the forestry enterprise, and is accountable to the Forestry Director. Forestry district area may vary from 5-8 up to several dozens of thousands of hectares, based on the volume of activities.

Forest fires – type of landscape fires, at which fire spontaneously spreads out in the forest. Forest fires can be surface fires – when the residue, leaf mold, moss and grass cover burn. The speed of fire spread is 1-3 meters per minute. Undergrowth and young tree stocks also get burnt in case of high speed surface fire. Surface fires generally do not cause much harm to the main tree stock. Crown fires – tree canopy also burns together with the grass cover, residue, and leaf mold. Crown fires spread unevenly at the average speed of 40 m/minute. Sometimes surface and crown fires come together. Ground/turf/ fires are characterized by flameless burning of 0,3-1,5m turf layer. The speed of the ground fire doesn’t exceed 7 meters per day; it may last from a day or a couple of days to several months.

Forest floor – accumulation of forest biocenose residue on the soil under the forest foliage, which is formed by forest litter layer, creating a favourable environment for animals and micro-organisms. Organic residue is at different stages of decomposition and humification at various layers of forest ground cover. The power of the forest floor is based on the structure, type, integrity, age of the forest stand, type and level of prevalence of the living cover, soil water regime, climate conditions, activity of rodents, and other factors. There are three types of forest floors: soft – which is formed in the forest stands of broadleaf trees under conditions of high temperature and low humidity, hard or acid – which is formed in fine-leaved and coniferous forests, under conditions of high humidity and low temperature; modern – which is in-between the previous two types. The amount of the residue reaches up to 3000 kg/ha annually in broad-leaf mature deciduous forests, 3000-6000 kg/ha in dry coniferous forests, and 25-30 per cent more in fresh and wet forests. It has a very important soil-formation function. It synchronizes the chemical reaction, water regime and physical features of the soil, improves soil fertility, creates conditions for the seed regeneration of the forest, etc.

Forest Impact on Climate (microclimate) –Forests have a slight impact on the climate in relatively scarcely forested areas and forest-steppe zone. Forest foliage decreases the temperature of air and soil under the foliage in the summertime by preventing the penetration of sun rays significantly, whereas the temperature increases fairly in winter due to the decrease of thermo-emission from the soil under the foliage. Evaporating huge amounts of water by transpiration, forest increases relative humidity of the air. Accelerating the condensation of vapour, forest results in the increase of horizontal precipitations (dew, rime), contributes to the accumulation of snow under the canopy and its even distribution, protects the soil from freezing, and creates conditions for the slow absorption of snowmelt water. It changes the direction and reduces the speed of wind. In dense forests the wind dies out at 200-300 meters from the edge. Blowing away the steams, wind causes an increase of humidity outside the forest.

Forest Inventory – Integrated forest description and mapping activity. It may be performed during forest management activities or upon special assignment.

Forest land capability class (bonity) – forest soil fertility indicator expressed in the growth of trees, their age, density, composition, type, origin (seed vegetative). It is determined at a relevant age by the average height of trees.

Forest management – utilization of useful properties of the state unified forest fund. Forest Code allows the harvesting of timber and secondary forest products (stump, phloem, bark, etc). Non-timber use of forest resources – using forests for research, hunting enterprise, recreation-health improvement purposes, etc. Water-conservation, protective, sanitary and other beneficial properties of the forest are also used. Forest utilization is performed upon special permit by logging licenses and forest use licenses. Terms are defined by RA legislation and upon the regulation of the authorized body.

Forest Map – Map with certain conditional signs to indicate biological and economic characteristics of the forests. They are widely used in the detection of forest resources, productivity assessment, conservation and protection of forests.

Forest Protection –1) Forestry department, which ensures the protection of the constituents (forest plantations, forest seed production units, etc.) of forest and forestry production from pests and negative environmental impacts. 2) Science on pest and harmful plant management mechanisms and methods. Forest protection studies and designs integrated prevention and control activities.

Forest Reclamation – Forestry branch that studies technological and organizational issues for land capacity improvement. It is based on soil protection, water-regulatory, water protection, and other functions of forests.

Forest section – certain section of a forest that is considerably different from the adjacent forest areas (by shape, composition, origin, age, forest capacity, type, integrity, etc.)

Forest seeding – establishment of forest plantations through seeding. It is performed to develop a new generation under old forest stands, as well to ensure the afforestation of the logging areas. It is performed after tilling the soil with horse-drawn equipment or hand-ploughs. Seeding seasons are fall and spring, but for the plants that are easy to lose their germination capacity it is done in summer. Seeds are covered with soil based on their size and the condition of the soil.

Forest Stand – a separate forest phytocenosis. It is a coexistence of trees and bushes that is biologically uniform by its assessment elements (formation, type, age, growth class, etc.) and is different from the surrounding environment. It comprises the young stock, underwood live cover (grass and moss). Separately standing trees cannot be called forest stand. Forest stand is mixed if two and more tree species participate in its formation. The mixed forest stand is called by the name of the dominating variety (oak stand, hornbeam stand, birch stand or oak-hornbeam stand, etc.).  Forest stand is pure if it is composed of one tree variety, and is called by the name of that variety. Forest stand is even-aged when it is composed of trees of the same age class (10-20 years), and it is multiple-aged if it is composed of trees of different age classes. Forest stands can be plain, if all the tree crowns are of the same height, creating one foliage; it is considered complex, when trees form foliage on two or more storeys. Complex forest stands have high efficiency and favorable environmental properties.

Forest Stand Age Classification – Forest stand is even-aged if it is composed of trees of the same age class. It is multi-aged if it is composed of trees of 2 and more age classes.

Forest stand diameter (average) – is a forest assessment indicator. Forest stand average diameter is calculated by measurements made on the 1,3 m level of the trunk in the uniform, even-aged forest stand, and by species and tree storeys in mixed and complex forest stands. Fluctuations of trunk diameters in the same species of tree at different storeys are a natural phenomenon. The diameter of the thinnest tree is generally 2 times less than the average diameter of the forest stand, and the diameter of the thickest tree is approximately 2,7 times more than the average diameter of the forest stand.  Forest stand diameter indicator depends on its age and growth class. It determines the type and composition of the tree along with the merchantability class. During the overall forest inventory, trees are classified by the diameter difference of 2 cm, if the average diameter does not exceed 32 cm, and based on the diameter difference of 4 cm for higher average diameter. At experimental sites forest stand diameter is measured at 0,1 cm accuracy level.

Forest stand quality (merchantability) class –wood merchantability indicator of forest stand. It is determined by the output of timber. It is applied in the assessment of growing and mature forest stands. Four forest stand quality classes are identified – 1) when the output in 1 ha area is over 70% in coniferous forest stand and over 45% in broad-leaved forest stand, 2) 51-70% and 31-44% respectively, 3) 30-40%, 4) 30% and below 10%

Forest stand stocking rate (density) – is determined by the number of trees per hectare and by the thickness of trunks. Forest stand can be differentiated into dense, of average density and thin. It is used in the evaluation description of the young stock and underwood. Forest stand density determination is highly important for the establishment of plantations and sanitary cuttings. It is defined by calculating either the overall number of the trees, or the number of the trees in the experimental site. The growth of the trees both height-wise and width-wise, self cleaning of the trunk from branches and self-thinning is based on it. The number of trees per unit of area decreases along with age.

Forest valuation scale – 1-5 yield classes are identified. The additional scale indicator used for the trees exceeding the size of the scale is 1 ha, 5 ha, 5b, which indicate that the average tree height in the given forest stock is above the first yield class (1ha) or below the fifth yield class level (5ha, 5b).

Forested area – Area covered by natural forests or coalesced planting stocks transferred to the state forest fund.

Fruit bearing – Plant vegetation, during which it blossoms and gives fruits. Fruit bearing has an interrupting, annually repeating character in the areas of seasonal climate. In humid subtropical areas no fruit bearing seasonality is observed. Fruit bearing age of different species is different. Free-standing trees reach their fruit bearing age earlier than the trees in the forest. As far as coniferous trees do not bear fruits, their fruit bearing process is called seed development.

Fuel-wood – wood used for fuel. It is harvested from trees and tree side-branches, with the diameter of over 3 cm in the upper cutting, which are not fit for use as timber.

Fuel-wood tree – a tree, which has trunk defects, or is short to be used for timber – does not exceed 2 meters.



Germination capacity of seeds – Two types of germination capacities are identified – absolute germination capacity (indicating the number of germinated seeds, regardless of the time period, expressed in percentage term) and technical germination capacity (number of germinated plantlets grown from planting of unselected seeds, expressed in percentage term)

Ground Wood – Trees or branches fallen by some natural cause – mostly dry trees. It mainly refers to the dry trees. Causes of the tree-fall are natural death, wind-fall, snow-break, damage caused by pests and diseases, wood-fire. It is particularly typical of young thick wood stands formed of deciduous trees (aspen, linden, birch, etc.) during trunk classification and intensive self-thinning.



Heaving of seedlings – occurs in the fall, sometimes in spring, when the upper layer of the soil (15-20 cm) swells due to the frost and when it melts the plants, roots or a considerable part of the roots of even 4-5 year old plants come out of the soil, bringing about drastic decrease of growth rate or causing plantlets to die.

High forest stand – Forest formed of long-boled trees of seed origin.

Hollow of a tree trunk – hallow in the tree trunk, skeletal branches, thick roots caused by the destruction of the wood. It generally appears on mechanically damaged areas of broad-leaf overmature trees due to the activity of saprophytic fungi, sometimes of ants and birds. The hollow is often used by birds and animals as a place to hide or as a nest.

Horizontal Canopy Closure – when crowns of trees at certain height come closer to each other and crown closure occurs. Degree of canopy closure is determined by a 10-point scoring system, which shows the degree of direct sunlight penetration through the foliage (what percentage of the soil surface is irradiated by the direct solar beams).

Hornbeam – Species of single-stem deciduous trees (rarely bushes) of Birch family. Height of the tree is up to 25 m, trunk is vertical, buttress, smooth and slightly chapped with a grey bark. The crown is thick, oval-shaped. One year-old shoots are thin, lanate at the beginning, bare later.  Leaves are dark green, arranged in two layers, simple oval-shaped, 5-25 cm long, with serrate edges.  Back side of the leaves is slightly lanate. Flowers are diclinous, greenish-red with up to 6 cm long hanging aments. Its blooming and leave opening seasons coincide. Fruit is a small nut. It bears fruit every year. Seeds mature in the fall, germinating capacity lasts up to 10 years. It may be reproduced by coppice shoots as well. The tree maintains its shoot generation capacity for up to 80 years, the stump – 3 years. Two species of hornbeam grow in Armenia – Caucasian and Eastern. Caucasian hornbeam (Carpinus caucasica) is a tree, with maximum height of 20 m, trunk diameter – 40-60 cm. It is a principal forest formation tree species. It lives 100-150 years, sometimes 300 years. It grows in oak and beech forest stands as a second-story tree species. Uniform hornbeam forest stands may sometimes be observed, which are mainly of secondary origin. It covers approximately 45 hectare, of which 8 ha are of stump-branch origin.



Inventory of forestry crops – inspections for identifying the quality and efficiency of forest crops, as well as for planning further forest plantation and management activities.  It is performed in the fall for 1-2 year old plantations, after the final plant growth cessation. Inventory of forest crops is conducted in experimental sites. Experimental site should occupy 5 percent of the territory if the plantation is up to 3 hectares, in case of 3-5 hectares – 4 per cent,  5-10 hectares – 3 per cent,  10-50 hectares – 2 per cent, over 50 hectares – 1 per cent. Forest crops with survival rate under 25 per cent are to be excluded.



Land Capability Class (bonity) – unit of forest stand (forest) efficiency assessment. 5 land capability classes-1-5, are identified in silviculture.  Based on the growth rate the following classes are also used – 1 ha, 5 ha and 5b, which show that the growth of the given tree is above the first or below the fifth land capability class indicators.

Life cipher – temperature at which sap movement and vital processes start in plants. It is +6-8˚C for most tree species in the temperate zone.
Lighthouse (reserve) Trees – trees that have high productivity and other positive features, which remain untouched during general wood-cuttings, to ensure the natural regeneration of forests by seeds.

Log – certain section of the tree trunk, which is used as special timber in aircraft construction, ski and resonance production, as well as in the production of matches, board paper, etc.



Marketability of Forest Stand – Unlike the land capability class, it shows the overall quality of the forest stand and not the soil conditions. In forest assessment marketability of forest stand, expressed by classes, is mainly used instead of the forest stand quality factor. Forest stand marketability class drops if there are infected dry trees available. If urgent cutting is required, the cut trees should be recorded in the registry and marked in red ‘P’.

Marketable volume of timber – covers the entire volume of the timber (without bark) and firewood. Volume of marketable timber reflects the actual volume of wood stand timber. During internal accounting only 90% is marketable. Small branches, together with wood bark, constitute the remaining 10 per cent.
Merchantable tree – tree with efficient usable portion of stem and with excellent technical features. Merchantable wood of the tree of above 20 m height is 6,5 meters and more.  Merchantable wood of short trees is not less than 1/3 of the tree height. Merchantable wood volume is calculated to estimate the monetary value of the forest stand.

Mountain forests – grow on mountain slopes and are of great environmental importance. They have the peculiarities of the vertical climate zone, absolute expressions of which are based on the geographical location of the forest and absolute altitude of the massif.



Native (Primary) Forest – forests that have grown in the same location without varietal changes for a long period of time, without any human interference. They are longevous, capable of self-regeneration, are comprised of trees that have biological feature completely relevant to the soil and climatic conditions.

Natural regrowth – Can take place in a natural way or through human interference. In both cases regeneration is called natural if no artificial seeding or planting is performed, even if soil preparation activities have been implemented.

Natural regrowth (in forest) – value, the change of which causes the expansion of forest stand resources during growth period. Factors affecting wood growth are as follows – biological features of the tree, origin of forest stand, age, density, sanitary condition, conditions of growth and forest management activities (intermediate cuttings in particular).Two types of growth have been observed – average growth and current growth, absolute indicators of which at the young age are about the same and small. They grow with age, reach their maximum level and gradually decrease at various rates. The increase in forest growth rate at the primary stage is above the average growth rate. Before quantitative maturity age, growth rate surpasses the average growth, but later becomes slower than that. Growth rate variation intensity mainly depends on forest stand density, which serves as a typical quantitative indicator to determine the bioactivity of trees and forest stand. Forest stand growth indicator expresses the nature of its growth, and makes it possible to determine the efficiency of the planned, as well as already performed forest management activities.

Natural thinning – Natural thinning of the forest is a result of natural selection, which takes place in the intricate coexistence of the environment and vegetation in the conditions of the cooperation of individual plant features. Weak trees, that do not adapt to the conditions, die out in that process. Plants that have advantages over the others survive and form a forest stand. Forest stand is formed spontaneously, by natural selection.  Forests formed spontaneously by natural selection do not always meet the practical requirements of the people, therefore, in order to have economically efficient forest stands, forest management interference is required in the thinning process, giving it a possible desired direction.

Non-timber use  of forest – any use (hay harvesting, animal grazing, bee-keeping, collection of fruits, berries, officinal herbs, mushrooms, etc. that are not related to wood ) of forest fund (in forest cover and non-forest area). It is of great economic importance for forestry.



Oak tree – Belongs to family Fagaceae, or the beech family. The family includes approximately 60 evergreen and deciduous tree and shrub species. The tree height is 30-40 m, trunk diameter is 1-1,5 and more. The foliage is vigorous, wide, cone-shaped, spread out or pendulous with thick skeletal branches. In dense forest stands the trunk is clean of side branches. The bark is dark grey, with deep longitudinal section. The leaves of ever-green tree species are small, whole or with serrated edges. Leaves of deciduous tree varieties are broad, 7-15 cm and more, the edges are cotyledonous-serrate. The leaves are small, monoclinous. Male flowers are long, have a light green colour, ament; female leaves are solitary, sessile or with long pedicle. The fruit is acorn with shiny brown shell. The size of the shell may be from a couple millimetres to some 5-6 cm. The root system is powerful, the main root is well developed.

Open Woodland – Short sparse forests, where tree crown is not closed. They are common in mountain areas, subalpine regions, valleys, on the borderline of forest belt and tundra. Light forests may be uniform and mixed. In arid, steppe and semi-desertic areas light forests are composed of diverse tree varieties, based on natural climatic and topographic conditions. Juniper, almond, nettle, pistachio and other trees participate in the formation of the open woodlands in the eastern Transcaucasus.

Origin of Forest Stand – it can be natural and artificial. Natural origin – seed, vegetative, coppice shoot, root-stock. Artificial origin – established by means of seeding, planting spermaphytes, saplings and sprigs. Forests of seed origin have high efficiency and longevity.

Overmature forest stand – forest age stage which follows the maturity stage of the forest stand. It is characterized by slow rate of growth in the upper storey. Overmature trees are often more susceptible to diseases, windbreak and snowbreak. Absolute forest maturity age, is based on the tree species and conditions of growth. The age of overmature forest stand is always above the cutting age, which is defined by the given technical maturity.



Percentage of Forest Cover – is determined by the correlation of the given area and the forests within it, expressed in percentage rate. The level of forest cover depends on the physical-geographic location and soil-climatic conditions. Its dynamics is based on natural phenomena as well as by human economic activities. Types of forest cover are – optimal percentage of forest cover, hydrological forest cover and necessary minimum forest cover.

Plantation – Uniform area of artificially planted forest.

Principal tree species – tree species that meets the economic requirements under certain wood growing conditions. It provides highly efficient timber of certain technical (physio-mechanical) and chemical properties.



Recreational forests – this group includes suburban woods, wood parks, green zones, as well as recreation areas located in wood health and recreation zones. Protection Forest belts of 50-100 m length and 50-250 m wood belt adjacent to tourism bases may perform a recreational function. Recreational forests are divided into zones of intensive and moderate attendance.

Reforestation – emergence of young trees under the foliage or in the former logging area to replace the old forest. Reforestation period may vary from one year to several decades. It is impossible to detect the begging and the end of reforestation in virgin forests and in the areas, where selective logging is performed, and where reforestation is an ongoing process. Reforestation of the cut-down forests terminates, when young trees coalesce and the struggle for the growth and formation of individual trees begins. It has two stages; initial stage – when young stocks emerge under the foliage before the logging of the forest, and subsequent stage – re-establishment of the forest after logging through natural seed dispersal or tree transplanting. By origin reforestation can be by seeds or vegetative (stump sprout, in particular). By the nature of regeneration it can be natural and artificial. Forests of seed origin are distinguished by their longevity, high efficiency and best environmental qualities.

Reforestation – forestation of the woodless areas by establishing artificial forests. It is performed by planting or seeding. Relevant tree and bush species and various soil cultivation methods are used based on the geographic location, relief and reforestation objectives.

Replenishment of Forest Stands – is implemented during the first two years of the establishment of the plantation to maintain the initial density through additional planting and seeding of trees and bushes to replace dried plants. Plantation replenishment need and amount is identified based on forest plantation inventory results. Replenishment is performed if the survival rate is 30-80 per cent, by using standard planting stocks that match the age and type of the plantation established in the particular area.



Sapwood – the section between the cambium and pith of the wood or mature wood. It is composed of dead and live parenchyma cells.  It is different from sapwood pith by its relatively light colour. In mature wood varieties it is possible to identify only in fresh cuttings. Sapwood is the physiologically active part of the trunk; the up-flow from the roots to the leaves takes place through its vessels.  Nutrients accumulate in the sapwood parenchyma cells. Disease immunity is based on its live cells. The volume of sapwood in the trunk depends on the species, age and physiological condition of the tree. Young tree trunks are composed of almost sapwood only.  Sapwood volume in the trees with thick crown is big. Its bio-resistance is lower than that of the pith.

Second growth (low) forest – forest that grows out of coppice shoots and root-stock.

Shrub-wood –forests of mostly coppice-shoot origin, which have lower efficiency versus seed-origin forests of the same variety in the same conditions.

Sideboard – board cut from the edge of the log

Single-storey forest stand – Single-storey forest stand, where the foliage of all the trees form one storey.

Small-leaved forests – Forests that are composed of small-leaved tree varieties –birch, aspen, alder, etc., which have soft wood unlike broad-leaved tree varieties. Small-leaved forests are mainly of secondary origin, developed as a result of human interference in the areas of coniferous and broad-leaved forests.

Sparse stand – thinned forest stand, with 0,3-0,1 density.  It may be caused by strong windfalls, or dying of individual trees or groups of trees due to pests or long-term drought, as well as by wrongly performed selective cuttings. Light forest is a negative phenomenon from the forestry standpoint; it reduces forest stand productivity and timber quality. Grass grows intensively in the sparse forest, causing turfing and hindering the natural reproduction of forest through seeds; thus forest stand loses its soil protection and water-regulating properties.
Sprouts (seedling, plantlet)



Timber – Big batch of wood mainly obtained for industrial use. It can be used as log or raw material for further processing.  Timber outcome may be up to 72% of the wood.

Timber harvesting – main use of the forest. It covers the entire process of cutting the tree, hauling from the logging area, and partial processing in the internal storage.

Tree Age – is determined by the number of annual rings on the base of the tree (next to the root neck). Annual rings of coniferous and stiff-leaved vascular species are fairly visible.

Tree diameter – The diameter of the growing tree is measured on the 1,3 meter height of the tree. In certain cases it is measured on the base. It is an important forest assessment indicator.

Tree dieback – mortality of trees caused by the self-thinning process in the forest stand. The main reasons are genetic features, correlation of various trees, conditions of growth, etc. In uniform forest stands mortality in young trees, before the closure of the crown, is a result of interspecies struggle; weak and sick trees are mainly affected. After the crown closure, tree mortality occurs due to the struggle of individual trees for light, humidity, soil fertility. Mortality rate between the stages of forest stand struggle and the maturity stage in the unit area is 95% of the total number of trees. Tree mortality after maturity is a result of their individual ageing.

Tree felling – cutting of the tree from the root in the determined direction. Timber harvesting starts from tree felling. To fell a tree in the determined direction, 1/2-1/4 of the trunk should be cut in the bottom of the trunk, 30-40 cm above the ground and the cut section should be removed; then tree-felling should be performed by sawing the opposite side of the trunk.

Tree form factor – is determined by the correlation of the tree volume (trunk with the branches) and the volume of the cylinder. Trunk surface of the tree at 1,3 m height is accepted as cylinder area.

Tree re-growth – addition of a new layer of wood each year on top of the previous layer, which results in the increase of the total layer of cambium and the tree size (height, thickness, volume). This indicator shows the tree growth dynamics, and enables to make tree growth projections for a certain period of time.
Trunk Analyses – special research to study age-related changes in the tree size by the main forest assessment criteria – age, diameter, height, cross-section area, number of species.

Trunk buttress –defect of a tree trunk shape. It is typical of all tree species. Buttressing can be round and costal.  It increases the oblique radial arrangement of the board tissues.



Underwood – bushes, sometimes third class trees, which grow under the forest foliage and are not likely to reach out to the parent canopy. It is mainly formed of shadow-tolerant tree species. Heliophytic trees may also be found in the undergrowth of thin forests. Its composition and quantity are based on the tree variety which constitute the stand, and integrated growth conditions. Undergrowth is of great silvicultural importance. Its moderate availability contributes to the forest soil formation, improvement of hydrological regime, natural seed regeneration of the forest, growth of the young stock, etc. Large underwood negatively affects forest seed regeneration by shading the soil surface.

Underwood – young trees in logging areas of the forest or under the foliage, which are to form the future principal forest – the first storey. It may be of seed or vegetative origin. The young stock is considered to be sufficient if its amount is sufficient for the formation of the future forest stand and is evenly distributed; it is insufficient if the amount is insufficient or it is unevenly distributed. It is reliable when the young stock has a well-developed cone-shaped foliage, and unreliable when its foliage has a shape of an umbrella. Sufficiency and reliability of the young stock depends on the density of forest and degree of crown closure.

Uprooting – removal of stubs from the soil together with roots, by exploding them with special equipment, and by hand combination method.
Vegetative reproduction of forest – vegetative way of natural growth of forest by shoots, coppice shoots, rootstocks, layering, and artificial reproduction by sprigs and saplings.



Vertical forest zone – can be lower, medium, upper, and alpine. It is typical of mountain areas, where the plant cover changes due to the elevation. Absolute length of vertical plant zone varies in different areas of the world, due to the geographical longitude, climatic factors – temperature in the first place.
Virgin (primary) forest – natural forest that has not been previously disturbed or influenced by human activity. Forests in the tropical zone can mainly be classified as virgin. In fact there are no virgin forests. All the forests are directly or indirectly affected by human activity (anthropogenic pressure).

Visual Taxation – description of the forest based on the observations from the airplane. Forest assessor makes the outline of the area and gives visual description of the forest by performing 1-1,5 km parallel flights over the forest.

Volume of Growing Stock (on the root) – reflects the sum total of the volume of all the trees or model trees in the forest stand. It is determined visually or by the measurements of all the trees or model trees. In calculating the forest stand stock, trees should be classified according to their diameter; then the height of various trees should be measured by hypsometer. In mixed and complex forest stands classification and calculation of trees is performed by varieties. Volume of average tree at each density level is calculated by using data of the diameter and height. Average tree volume should be multiplied by the number of trees in the given group to find the volume of the group. Sum total of the volume of different groups reflects the volume of growing stock on the root. It is expressed by the following formula – M = ΣQHF, where ΣQ is the sum of the tree trunk area expressed by m², F is a variety number, and H is the average height.



Water protection forests – woods that ensure the even outflow of spring waters, and increase or maintain the water amount under dry conditions. Positive impact of water protection forests is based on the age, density, geographical, topographical and other factors of the forest stand.

Water-regulating role of forests – forests prevent surface flow caused by precipitations, turning it into underground flow. They help to maintain the level of spring waters and rivers steady.  Evaporating enormous amount of water /transpiration/, they prevent swamp formation and contribute to the soil drainage.
Wind break – when wind breaks the tree trunk below the foliage.

Windfall – a tree or a part of the forest stand fallen by wind.  Trees with surficial root system and trees having rotten roots may fall due to the wind. Trees that are left alone after the cutting of a thick forest are likely to suffer the consequences of strong winds (20-25 m/s) most.

Windfall – Deformation and decomposition of rocks under the influence of atmosphere-surface waters, winds, activities of plant and animal organisms. It can be physical and chemical. Physical windfall is caused by temperature fluctuations, which results in the destruction of hard rocks under the influence of water. Water is the main cause of chemical windfall; intensity of decomposition process depends on the amount of carbonic acid (gas) diluted in it. Destructive influence of water increases with the increase of its temperature.

Wood – Tissue formed of cambium that plays a mechanical and storing role of the transporter of materials from the root to the leaves. Wood is mainly comprised of the trunk, branches and roots.

Wood cutting area – Forest section, separated by special signs (columns) or natural boundaries, designed for timber logging. Wood cutting area can be of different shapes – square, rectangular, cuneiform, etc. Its main elements are the length, term and method of crown closure, felling direction, seeding sources, timber logging season and methods, cleaning period, etc. The size of the wood cutting area depends on the forest class.

Wood Density – physical indicator showing the correlation of the actual and general volume of the wood. It is defined by the following formula – Q=m/v, where “m” stands for weight of the wood sample and “v” stands for the volume.

Wood flour – outcome of the wood waste mechanical processing (sawdust, shaving, sometimes leaves). It is used as animal feed.

Wood-fire control – various methods are applied based on the nature of the fire – chemical, explosion, counter logging, digging ditches, counter fires, etc.



Young forest – prime age phase of the forest consisting of trees from young to pole-wood ages. It has two phases – before and after the crown closure, when inner branches of trees start to dry due to insufficient light. Tree trunks and foliage begin to form, and poorly grown trees die out at the second stage of the young forest. Young forest phase of coniferous and sclerophyllous trees ends at 20-30 years of age, it ends at 10 years of age for soft-leaved trees and bushes. Sanitary (for the purpose of light penetration and cleaning) cutting activities are applied to ensure proper conditions for the growth and development of young forests.

This post is also available in: Armenian