Forest Resources
According to the available definition of the Food and Agricultural Organization (FAO) agreed on by all member states, forest is an area covered by trees with the height of 5 meters as well as the canopy cover of more than 10 percent, covering a minimum area of 0.5 ha at least . In this definition, the capability of trees to reach to the height of 5 meters is emphasized and therefore, plantations on agricultural lands or in urban areas do not include the instances of this definition. Some countries however, use other indicators to determine their forested areas based on the significance of forests in their regions. Therefore, in view of the scattering of forested areas and legal restrictions in Iran, which are among some of the preventive factors for defining forests, a canopy cover of more than 5 percent is accepted for the definition of forest areas here in Iran. In line with this definition, Iran s forest area is estimated at 12,400,000 ha.
According this definition, Iran s natural forested area is estimated at 13,283,901 ha. Adding another 919,468 ha of plantations to this figure, Iran s forest area is estimated at about 14,202,559 ha (equal to 9 percent of the country’s land area) and as a result, forest per capita is 0.2 ha as compared with the global standard of 0.8 ha. Iran s forests are divided into two areas including the Caspian forests in the north and dry and semi-dry forests. This is shown in the following table:
Table no 2: Iran s forest area unit: ha
|
Forest types
|
Dry &Semi-Dry
|
Caspian
|
Total
|
Percentage
|
|
Closed Forests*
|
755,777
|
940,826
|
1,696,603
|
12.0
|
|
Semi-Closed Forests*
|
2,806,846
|
593,927
|
3,400,733
|
23.9
|
|
Open Forests*
|
7,842,183
|
313,133
|
8,155,316
|
57.4
|
|
Mangrove Forests
|
30,400
|
0
|
30,400
|
0.2
|
|
Planted Forests
|
919,468
|
0
|
919,468
|
6.5
|
|
Total
|
12,354,673
|
1,847,886
|
14,202,559
|
100.0
|
*Canopy Density in closed forests is more than 50 percent, in semi closed forests is 25 to 50 percent and in open forests is 5 to 25 percent.
Ecologists and botanists have divided Iran s forests into five vegetation regions with due consideration to climate. They are as follows:
1. The Hyrcanian Forests
Forests located in the northern part of Iran, also known as the Caspian forests or Hyrcanian forests; belong to the end of the third geological era. The Caspian forests are known as the oldest forests in the world. These forests form a rather narrow green belt bordering the northern part of the Alborz Mountains and extend from Astara in the west of Gilan Province to Giledarreh in the east of Golestan province, and are about 800 kilometers in length and 20 to 70 kilometers in width. The Caspian forests are extended at the altitude of a maximum of 2800 meters from sea level and comprise a mixture of beech, blue beech, oak, maple and alder.
Fertile soil, proportionate precipitation and high humidity have created a varied collection of plants in this region, including about 80 species of trees- mainly deciduous species- as well as four species of conifers and 50 species of shrubs of which the most important are: Fogus orientalis, Acer insigne, Acer Cappadocicum,Ulmus glabra, Fraxinus excelsior, Tilia begonifolia,Cerasus avium, Quercus castaneifolia, Zelkova carpinifolia,Alnus subcordata and Carpinus betulus.
The area of these forests, based on the latest FRWO statistics, is about 1,847,886 ha of which 940826 ha closed forests, 593,927 ha semi-closed forests with 25-50 percent canopy cover and 313,133 ha open forests with 5-25 percent canopy cover. Due to the eco systemic and environmental values of these forests as well as their socio-economic role in the lives of the people in this territory, these forests are known as one of the most basic resources for wood production and have a big share in supplying wood to the related industries. FRWO has, however, decreased wood harvest from these forests in accordance with a regular program during the last 10 years and the necessary wood needed for industries is supplied through importation and development of wood culture.
2. Arasbarani Forests
These forests cover an area about 15000 ha and are located in the north east of East Azerbaijan province in the watershed basin of the Aras River. The area’s sub-humid climate has created a semi-closed forest in this region, and although the annual precipitation fluctuates between 300 to 600 mm, the occurrence of an almost permanent fog has increased the humidity of the soil.
Arasbaran is characterized by varied plant species and most of the forest species of the Hyrcanian region can be found in here. However, lack of the main tree species of this region such as beech and alder, has differentiated it from the Hyrcanian region. The region of Arasbaran has been registered as the world’s foremost genetic reserve for its high biological variety, and so far more than 775 plant species have been identified in protected areas alone, of which 55 species have been reported for the first time from Iran. There are about 100 tree species, the most important of which are as follows:
Acer, compestire, Amygdalus sp., Carpinus orintalis, Celtis australis, Cornus mas, Corylus avellana, Ficus carica, Fraxinus rotandifolia, Juglans rejia, Juniperus communis, morus sp., Pistacia mutica and Quercus komarovii.
The Arasbarani forests have also been registered in UNESCO s biosphere reserves. This region has been protected for the last 30 years and it is the main habitat of some of the world’s rarest fauna.
3. Irano – Touranian Forests
The region is recognized as the vast vegetation region of the country and encompasses about 75 percent of Iran s land area. It is located in the southern part of the Alborz Mountains, the north east, the east and central area and parts of south eastern Iran including Barez mountains, and is home to 69% of Iran s flora. Having very little precipitation and a long arid season, on the whole differentiates the region from other parts of the country.
The heat fluctuations are very intense and the intensity of summer heat in central parts of this region is similar to the heat intensity in African deserts. Winter in the cold regions of these forests is more severe than the winter in the Mediterranean region. Because of the vastness of area and climatic differences, the forests of this region are divided into upland and low land regions.
Some of the species which can be found in this area’s upland region are;Juniprus ploycarpus, Pistyacia mutica, Pistacia vera,pistacia khinju and Amygdalus spp with the Juniprus ploycarpus forests in Hezar masjed in Khorasan, Chahar Baq in Shahrud and Sardoea in Kerman being the most important of Juniprus ploycarpus forests. Also the Pistyacia muticaand Amygdalus spp forests in Bakhtegan Lake in Fars province and those situated along the Barez Mountains in Kerman province and Badamak (Badamashk) in the south Khorasan are the most significant forested regions of this zone.
In the low land region, desert forests species such as Tamarix spp, Haloxylon spp. ,Zygophyllum s. and,Calligonum sp. are grown.
The forest area of this region is estimated at 4,100,000 ha and has no commercial value in terms of wood production. The typical forest exploitations in this region are fuel wood production, forest products which do not rely on wood and grazing. These exploitations are among the most important factors contributing to forest degradation.
Prior to the nationalization of forests and rangelands in 1962, overexploitation of forest, especially the Juniprus ploycarpus, and Zygophyllum species for fuel wood and wooden poles, incurred heavy degradation to forested areas in the Irano-Touranian forests. However, in recent years, as a result of the improvement of subsistence of local communities and also the supply of fossil fuels, the degradation of forest in the area has slowed down.
4. Persian Gulf and Sea of Oman Forests
This region extends from Qasr-e- Shirin in the west as a narrow strip to the southern part of Iran passing through Khouzestan, Boushehr and Hormozgan provinces, to the border with Pakistan. The mean annual precipitation ranges between 100-250 mm, generally increasing from east to west, whereas annual humidity increases from west to east. Ecological differences and variations have divided the region into Persian Gulf and Omanian regions.
The Persian Gulf territory is bound by Qasr-e- Shirin up to the border of Boushehr and Hormozgan provinces. The main trees and shrubs of this region are Zizyohus spina christi, Prosopis farcta and Zizyphus nomularia . The Omanian region contains territories of Hormozgan and Sistan & Balouchistan provinces and the main trees and shrubs to be found here are Prosopis spicigera, Acacia tortilis , acacia nilotica. A.nubica can also be found scattered in this region and its wood is used for the ship-building industry. Other main tree species of this region are: Albizia lebbek, Capparis decidua, Calatropis procera ,Ficus bengalensis, Haloxylon spp.,melia indica, Nerium indicium,Prosopis,juliflora,procopis specigera, Taramix spp., Tecomella undulata, zygophyllum sp. and Salvadora persica.
Mangrove forests consist of two species of Avecina marina and Rhizophora mucronat which can be found along the coastal line of the Persian Gulf and Oman Sea, particularly in the north of Qeshm Island. These forests cover some 25000 ha and are the habitat of a number of valuable species of marine animals and sea birds, and have special bio-ecological value.
The total area of this forest is estimated at about 1,100,000 ha, and is significant in terms of genetic reserves, water and soil conservation as well as wild life protection but has no value as regards wood production.
5. Zagros Forests
The Zagros Mountains extend from the North West border (south of Ararat Mountains) up to the Straits of Hormoz alongside Hassan Longi River in the west of Minab. This mountain range covers the west side of the country parallel to the western border and therefore are under the direct impact of the sub-humid climate from Black Sea and the Mediterranean Sea in the form of precipitation and thus creates a suitable condition for forestation. The forests in this region are located in Western Azerbaijan, Kurdestan, Kermanshah, Ilam, Lorestan, Chaharmahal-e- Bakhtiari & Boyerahmad as well as some parts of Fars province. These forests were denser and much vaster in the past. The remaining forest is a protected area bordered by the Piranshahr to Sardasht road in Western Azerbaijan province (known as Qabre Hossein) up to Firouzabad in Fars province, about 6,100,000 ha. However the remaining oak forests in Hamedan and Markazi provinces prove that there were vast and dense forests in Zagros forests in the past. There are about 200 ha of oak forests in Gian - Nahavand in Hamedan province as well as about 3-4 ha in Shazand - Arak in Markazi province.
The principal species of tree found in the Zagros forests is oak which has been able to survive despite heavy felling as well as overgrazing in the area. It should be mentioned that if there was not coppice ability, the western forests in Iran would be destroyed.
The most important plant species in this region includes Quercus infecturia, Q.libani and Q. brantii which can be found in the Zagros forests in addition to other tree and shrubs species like Acer Persicum , Amygdalus spp.Berberis vulgaris, Celtis caucasica, Crataequs sp,Cotoneaster sp, Cupressus horizantalis , P. Fraxinus sp., Pistacia mutica, Pistacia Khinguk, Prunus sp and Pyrus sp.
It is an undeniable fact that the Zagros forests contribute to soil conservation as well as approximately 45% of the water supply in Iran and also contribute to the development of the economy in the country.
Caspian Flora
The Caspian region due to receiving high precipitation and humidity contains the industrial forests of the country and is divided into three altitudinal categories as follows:
1. Lower altitude (800 meters)
There is no significant rangeland in this area instead it consists of a narrow coastal belt covered by age old species. The main species in the area are Setaria spp., and from the age old graminaceous family and perennial grasses, Dactylis glomerata, Poa spp., Festicubs ovina, Stipa sp. and Melica sp.
There are a few species of potherbs to be found here and also disperse species of Trifolium,Medicago and Onobrychis.
2. Mid altitude (800 to 2000meters)
Most areas of these forests have poor herbal cover because of the density of the forests, although some species of the perennial graminaceous family like: Agropyron panormitanum, Aristella bromoides, Festuca Montana, Poa spp., Dactylis glomerata, Bromus sp.and Melica sp. are found in the open and sun-lit areas. Potherb family plants such as white and red clovers and holy clover are rare and some species of goat s thorn may be found in the higher altitudes which usually are from the Irano-Touranian flora s elements.
3. Higher altitude (more than 2000 meters)
This region that is also called the alpine forests region and has a cold and arid climate which is rich in the perennial germanium family with species of; Bromus persicus, DasDastylis glomerata, Trisetum spp., Agropyron spp. Festuca spp. and Poa spp. Potherb family plants are the same as can be found in mid altitude. There are also a considerable amount of vegetation like Astragalus spp., Onobrychis cornuta, Acantholimon spp. and Acanthophyllum spp. in arid zones.
Balouchi Flora
The flora of this region differs from the flora found in the Caspian region due to site differences. The main species of this region are generally tropical plants of which the most important are as follows: Panicum antidotale, Cenchrus ciliaris, Pennisetum dichotomum, Aeloropus spp, aristida spp. and Hyparrhenia hirta. Potherb family plants of tropical regions are species of: Cassica, Taverniera, Tephrosia and Indigofera all of which are plenty in number. There is also a few goats thorn. Species of Salsola, Suaeda and Cornolua genus can be found in Shoushtar.
In the northern parts of this region and in heights where the climate is more arid and similar to warmer parts of the Irano -Touranian region, the above mentioned species disappear and are very rare, instead there can be found perennial germaniums such as: Aristida Chryspogon & Pennisetum orientale, Cymbopogon laniger and Plumosa ciliolatus.
Irano-Touranian regions
This region covers more than 85 percent of the land area of Iran and is quiet unique in terms of distribution and number of species in the country, especially goat s thorn geneses: Astragalus with more than 600 species. There are also many species of Silen Cousinia, Allium , Nepeta, Euphorbia, Centaurea acantholimon, Salvia and Onobrychis in this region.
The flora of Irano-Touranian region is divided into five sub- regions due to site differences as follows:
1. Semi-desert sub-region
In this sub- region the mean annual precipitation is less than 100 mm. It is located in Iran s central deserts and is covered by species of sponges such as: salicornia, Salsola spp., Seidlitzia herbacea, Halocnemum strobilaceum and Rosmarinus.
Other species of sponges like Suaedo, Holoxylon and Cornulaca may be found in the saline conditions of these sandy lands, down hills and stony slopes.
Perennial graminaceous rarely grow in this region, but species such as Zollikoferia, Stellera, Echinops. Fagonia, Astragalus and Reaumuria can be found in this sub region.
2. Steppe sub-region
The mean annual precipitation of this region ranges from 100 mm to 230 mm and the vegetation groups that grow in this sub-region are very varied and subject to the cold temperature of winter.
The Artimisia sieberi species along with semi- wooden species such as: Noaea mucronata, Anabasis sp., Haloxylon spp., Salsola rigida and Scariola orientalis can be found throughout the area.
Aristida plumose and stipa barbata as perennial graminaceous are typical of this region and grow in less hot areas, whereas in warmer places some species such as Aeluropus sp. Hyparrehenia hirta, Cenchrus ciliaris and Pennisetum dichotomum can be found.
The species Zygophyllum eurypterum is found in large numbers in this sub- region together with Santonica. Potherbs are rare in this area but goats thorns are found in large numbers. Overexploitation in this sub-region has destroyed most permanent species and vast areas are occupied by invader species like: Peganum harmala and Stipa copensis.
3. Semi -steppe sub-region
The mean annual precipitation of this region increases up to 400 mm. This sub-region represents several climatic zones and this has produced a rich flora but unfortunately dry farming development has extensively destroyed rangelands and degraded the soils. This has also deeply changed the vegetation types for instance Santonica species rarely grow in this area although it has been replaced by Artemisia ausheri and A.maritima . Thorny species like Lactuca orientalis and Noaea mucronata are found throughout this area and Gundelia, Acanthoohyllum, Acantholimon, Astragalus cousinia and Echinops types are also plentiful. The plants relating to the Labiatae family, especially Marrubium, Ajuga, Ziziphors, Nepeta, Stachys, Phlomi and Teucrium genus also grow in large number throughout the area. There are also some species of the graminaceous family including Agropyron spp., Bromus tomentellus, Stipa barbata, Festuca ovina and Secawe montanum found here. Perennial potherbs including species of goat s thorn and fenugreek are also found in this area.
Overexploitation has led to the decline of the some species in the rangelands of this area, and has been replaced by invader species such as: Geobelia, Phlomis persica, Rosa persica, Alhagi camelorum, Salvia, Gundelia tournefotii, Euphorbia spp., Alopecuroides, Centaurea spp , Cousinia spp, Achillea santolina and Syriaca.
4. Arid forests sub –region
The mean annual precipitation of this region is 400 mm. In the past it used to have a favorable condition mostly for oak forest species, however, unfortunately there are only small forest areas, especially in the Zagros region up to the altitude of 2600 meters at the moment, due to overexploitation in past decades. The condition is more tense in the under- storey of forest where the livestock graze. Age old plants prevail in the lower altitudes. Stipa copensis and Aegilops spp are the prevailing plants in the lower heights. The perennial graminaceous like Hordeum bulbosum, Bromus tomentellus, Festuca ovina, Melica spp. and Agropyron spp. are found in the higher altitudes. The most significant species of the perennial potherb family in this region are: Astragalus spp. Onobrychis coronata, Terigonella eliptica. Also some species of spearmint family Labiatae and Compostae are found there. The thorny and invader species like Euphorbia, Scariola, Salvia, Phlomis, Astragalus and Cousinia are found considerably.
5. High mountains sub –region
The flora of this sub-region grows at an altitude of 2,600 meters up to the altitude of 4,500 meters. Trees and shrubs do not grow above the altitude of 3,000 to 3,200 meters. Vegetation here is varied, despite a restriction in growth period (less than 3 months above the altitude of 3,000 meters). The region is rich in flora due to a limited exploitation season and little interference from mankind. It is covered by perennial plants as well as cushion species such as Astragalus, Onobrychis and Acantholimon. The perennial graminaceous like Alopecurus, Hordeum, Melica, Stipa, Festuca, Agropyron, Poa and Dastylis are the principal species in this sub-region and there are several species of potherbs to be found in the high mountains as well as some clover species. Some of the significant species found here are; Nepeta, Phlomis, Thymus, Allysum, Dianthus, Achillea, Euphorbia, Helichrysum, Erysimum, Cousinia, Silene, Ephedra, Scropholaria and Ziziphora