The diversity of plants in forests understory is important from different perspectives. Thus, present research was carried out to find the chorology, origin and diversity of the understory plants species in Asalem's forests, northern Iran. Basic studies were conducted on the geographic characteristics of the region. The direct visiting forests method were selected for investigation of tree and understory plants species (herbs) which lasted of the year 2017 to 2018. Sampling of understory vegetation were done, recorded and identified based on available scientific references. The results showed that there are more than 152 species belonging to 124 genera and 61 families existed in forest understory. The largest families were Asteraceae, Rosaceae, Poaceae and Apiaceae with 17, 13, 11 and 10 species, respectively. Investigation of the geographical distribution of plant species indicated that there is a composition of Europe–Siberian, Iran-Turan, Mediterranean (and Polyregional and cosmo) plant elements. Plant life forms by Raunkiaer method showed that phanerophytes with 28 % and Chameophytes = Therophytes with 26 % are the most frequent life forms in this area. Also, plant diversity was higher in areas with sparse tree cover, but in degraded areas or areas with high tree vegetation understory plants diversity was low.

Keywords: Flora composition, Life form, Diversity, Asalem forest area

One of our greatest natural assets around the world, forests provide different ecological, social and economic services.¹ Plant vegetation in forest areas has importance in different aspects not only in term of wood production, but also in other non-woody production such as forage, medicine, beauty and etc. This productivity and diversity of forest is one of the best guide judgments about the ecological condition of the region. Because the plants are resistant organisms have endured in the long term conditions² and have adapted with own environmental factors. Beside the forest utilization, investigation of the plant diversity is important and it will show like a document history for the any region. In this regards, the most effective method, floristicall study investigates the geographical and floristically origin of each region for genetic resources managing.³ Identification and conserving forest biodiversity, especially understory herbs is therefore a valuable national and international work which focused on the creation of protected areas.⁴ However natural forest reserves are a critical part for conserving biodiversity in forests but are not sufficient and about 92% of the forests are outside formally protected around the world.

From the global, to regional there is many different forest ecosystem in term of diversity which determined by the combination of natural factors.⁴ It is therefore vital to adopt appropriate methodology to help ensure the long-term sustainability¹ especially for forest reservoirs in a changing world. To this end, the study of the plants diversity in forests understory around the word will be important in order to achieve conservation objectives and various exploit aspects. Therefore, the aim of this study was to determine florist list, chorology and diversity of the forest understory plant species in Asalem's forests (belong to Shafarood company) in northern region of Iran.

Study area

Asalem's forests area is located in southern Iran, in the Guilan province. The climate of the study area is very humid and the mean annual precipitation is 1365 mm and the mean annual temperature is 13.7 centigrade.4 Study area consists of different series as below: Nave1, Nave2, Nave3, Gilesara and lomir1 which are located at Geographical location (u.t.m) 51˚ 37ʹ 37˝-16˚ 41ʹ 37˝ and 51˚ 48ʹ 48˝- 27˚ 52ʹ 48˝ in a range of 250- 2150 m abs (Figure 1).

Figure 1 Geographical location of Asalem basin (Shafarood forest), Iran.

In order to plant study, the field visiting was performed favorably and also herbarium task were done to identify the left species. Therefore, different plant species samples were gathered during 2017-2018 and were identified. Identification was performed in two ways; using scientific references and local people’s knowledge. Also, those species which were not identified based on field observation, were identified in herbarium of the Tehran University. Along the field sampling, photos were also taken from the different species, which were used for laboratory for identification. Plant species identification was done based on different scientific reference and flora. Also, plant specimens were identified, named based on the different classification included Flora Iranica,⁵ Flora of Iraq,⁶ Flora of Iran (Assadi), and Flora of Ghahreman.⁷

Despite the low area and the presence of shadows in the Asalem forests, the diversity of plants was highly evaluated. The obtained results on the floristic diversity of Asalem forests were categorized in Table 2 in taxon in family groups. Totally 152 species belonged to 124 genus and 61 families of plant species plants species were identified in the in Asalem basin (Shafarood forest) mentioned region. Except of some families which contain only one species and genus in this area, the others of families have several species. The percent of species in this area with plant family has been demonstrated in the below Figure 2. The results of the flora Study showed that, there is a wide variety of herb plants in the region. Although the area is not vast, but herb plants have high percentage -more than 90 percent- of the total plants with diverse life forms due to the location of the area in hyrcanian zone. The total life forms of plant speciess plants are revealed in Figure 3 that, are classified based on Raunkiaer (1943).

Figure 2 Plant species plants percentage in different families in Asalem basin (Shafarood forest), Iran.

Figure 3 Percentage of different herb plants’ life form in the region. Ther, Therophytes; Geo, Geophytes; Phanero, Phanerophytes; Chamae, chamaephytes; Hemicrypto, hemicryptophytes in Asalem basin (Shafarood forest), Iran.

Also, plant diversity for each of the series is presented in the following table. It seems that understory plants are much more diverse compared to existing wood species, which are mostly a species of trees. The results of diversity indices in each the seri shown in Table 1 which showed a variation between species in different series. In this area plant diversity indices (Shannon, Simpson, Menhinick, Margalef, and Fisher alpha Index) is different in each region. This is mainly due to the predominance of tree species or the effects of external factors like humans in the region.

The value and importance of existing reserves about the forests are still being ignored. In terms of forest products, unfortunately, non-wood products have been neglected in many forests while there is a valuable reserves from the aspect of vegetation diversity (in forest understory). Meanwhile, the change in global ecology issue will affect almost all the forest conditions and may endangering the survival of species in forests.⁵ Therefore, this is important to identify understory plants diversity of forests around the world. In forests, identification of plants, understory plants specie specially, is the first step related to plant issues and their usages. Thiess plants may be used for many purposes and in this area some species due to have beautiful flowers, have a medicinal effect and etc. are of great importance. Therefore, evaluation of biodiversity reserves (plants species specially) is the first degree of importance and is the first step in terrestrial ecosystems management as well.

An overall review of other related studies show that this application type is mostly ignored in other areas, whereas 16% of understory plant species in this area are used for decorating the houses and living spaces. These plants are the symbol of nature for local people and they can touch the nature all the time. In Asalem forests, some of the plant species in forest understory are sold as an income resource for local community. Also some parts (seeds, leaves and stems) of limited plant species such as Heracleum persicum are used in food, but is destroyed in some place due to over-harvesting. The research also showed that there are many different plants species in this area in different family and genus. More than 152 species belonging to 124 genera and 61 families existed in the study area (Asalem forest) was recorded. Similarly, Ravanbakhsh and Amini⁴ disclosed a number of 76, 66 and 45 which are species, genera and plant families, respectively for Gisoum forest area. The largest families were Asteraceae and Rosaceae with 5 species. Investigation of the geographical distribution of plant species indicated that 44 % belonged to the Europe – Siberian zone. Plant life forms by Raunkiaer method showed that phanerophytes with 35.5 % and hemicryptophytes with 27.6 % are the most frequent understory plants life forms in this area. Yazdanshenas et al.⁸ also reported a vast range of different annual and biannual plant species in western area of Iran’s Isfahan which are mainly belonging to Asteraceae, Papilionaceae, and Apiaceae with 21, 15 and 12 percent, respectively. Based on the results in this research, the largest families were Asteraceae, Rosaceae, Poaceae and Apiaceae with 17, 13, 11 and 10 species, respectively. Investigation of the geographical distribution of plant species indicated that there is a composition of Europe – Siberian, Iran-Turan, Mediterranean (and Polyregional and cosmo.) plant elements (Figure 2). Just like that competition limits diversity when superior competitors increase in abundance until other species are excluded Wright,⁹  and similarly, in this study, understory plants diversity showed higher value (Table 1) Simpson Index= 0.64 for Nave1) for areas with low tree cover. Similar to this, Tárrega et al.¹⁰ reported that trees distance had a positively correlation to diversity and to annual species richness based on Shannon index, and a negative correlation to woody cover in the understory.

Like many other areas, some areas of Asalem’s foreste destroyed due to over using. Anthropogenic pressure alter the understory vegetation in forests.¹¹ Moreover, deforestation often creates matrices of human-managed areas, secondary vegetation regrowth and fragments of primary forests¹² and this is should be noted in forest areas. But utilization and consumption should be done based on ecological principles to ensure sustainability and conservation of the resources.¹³ Therefore, non-destructive harvesting, conservation, recovery of threatened plant species and proper management should be mange for plant conservation and their usages. Moreover, this is vital to identify their ecological needs, and propagation of the forest understory plant species. And sometime depends on local beliefs and capabilities, the ease of cultivating and economic potential these plants can be cultivated.¹⁴ However, recognition of the forests understory plants species by stakeholders has a paramount importance¹⁵ and should be studied more in the future. For this proposes forest management can significantly affect both the diversity and spatial patterning of understory vegetation.^16,17 Moreover, as time passes and changes occurred in available forests, non-timber forest products should become more and more important and utilized ecologically-based. For this, identification of the understory plants species is the first and most important step in sustainable forestry. The results of this study also showed that the there is a very high diversity of understory plants in Asalem forest which consists of a range of important herbaceous plant species and are often not seen in the forest generally.

The authors would like to express their thanks and appreciation to ETKA organization and Shafarood Forest Company of Iran for providing the research facilities, and special thanks to Prof. Mozaffarrian (Research Institute of Forests and Rangelands) for his help in plants identification.

The author declares there are no conflicts of interest.

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