Checklist of Trees of Uttar Pradesh, India:An Account to Understand their Nativity and Phenology

Introduction:

The trees are key ecosystem engineers [1]. Among the vegetation types, trees hold key position with respect to forest and ecosystem health [2]. They act as pollutant absorbers, natural coolers, rain promoters and producers of a number of economically important products. The increased demand for space, tree-based timber and non-timber products, developmental activities, etc. creates severe threats for tree vegetation [3]. In the recent past, the numbers of tree species were either extinct or facing problems of extinction because of unawareness or overexploitation. According to maximum workers tree species are rapidly disappearing and the genetic diversity of tree species is more vulnerable than the other plant species [4].  To check the extinction of tree species the prerequisite condition is the availability of a comprehensive document on the tree species present in a particular area. If these comprehensive documents also contain information on phenology, native range, and vegetation type of the tree species then it becomes more worthwhile with respect to sustainable management of forests, formulation of conservation strategies, assessment of effect of climate change, etc.

The state Uttar Pradesh is situated between 23.52° N to 31.28° N latitude and 77.3° E to 84.39° E longitude, covering 243,286 Km² area. It is 4^th largest state of India and comprises diverse geographical regions viz., Himalayan foothills in the north including Terai and Bhabhartracts,fertile Gangetic plains in the central part, Vindhya hills and plateaus in the south[5,6,7,8]. The state has rich drainage systems including the Ganga, Yamuna, Sarayu, and Ghaghara, with tributaries like the Ramganga,Gomti,and Betwa. The climate of state is humid sub-tropical with three distinct seasons, and averagetemperature ranges between 25-40⁰C during summer and 7-15⁰C during winter.Annual rainfall ranges from 600 mm in the western arid zones to 1500 mm in the eastern regions. Forests cover 6.09% of the state, comprising tropical dry, moist deciduous, and evergreen forests [9,10]. Uttar Pradesh’s rich biodiversity is reflected in its protected areas (1 National Park, 25 wildlife sanctuaries, 10 Ramsar sites). These areas harbor endemic, rare, and economically significant species, contributing to the region’s ecological wealth. 

The enlistingof trees is not only the inventory of tree diversity and genetic diversity but also relevant for forest and biodiversity research, forestry, agri-horticulture, silviculture, landscape management and conservation biology of rare, endemic and endangered tree species. Further, correlation with phenological data and nativity of species in different climatic conditionsis helpful in predictingthefuture of the species under future climate change [11]. It has been noticed that reproductive and vegetative time varies with species considerably from year to year in different areas and climates. Such phenological data is very relevant for tree breeders who must have knowledge about the phenology of tree species for seed collection, propagation, grafting, etc. It is also important for entomologists to study the correlation between insect cycles and stages of tree growth [1,12].  Considering the above facts, the present study was carried out with the objectives of documentation of species diversity among the trees with phenology and their nativity ranges.

Materials and Methods:

The present investigation is based on secondary datacompiled from authentic online and offline sources of literature.The distribution of tree species along with data regarding habits, phenology, and native range were collected and analyzed. The botanical names of the tree species have been updated according to the POWO (Plants of the Word Online; https://powo.science.kew.org). Angiosperm phylogeny Group IV classification for families of flowering plants has been followed while preparingthecomprehensive list of trees of Uttar Pradesh[13].

Results and discussion: In thepresent study 378 tree species are documented belongingto 55 families and 221 genera. Fabaceae represents as the most dominant family with 54 tree species followed by Euphorbiaceae (32 spp.), Bignoniaceae (24 spp.), Malvaceae (16 spp.) and Rubiaceae (13 spp.).Acacia present as the most dominant genus includes 14 species followed by Ficuswith13 species. The phenology of trees has been classified into 4 different quarters: 263 species undergo the flowering and fruiting phase during January – March (1^st quarter),   300 species in 2^nd quarter (April-June), 248 species in 3^rd quarter (July- September) and 216 in 4^th  quarter (October-December). With respect to phenological events, the month of March to June is recorded as most suitablein which a maximum number of species are in the flowering and fruiting phase(Table-1 & Fig.1). It is valuable information for researchers who are working on climate change, phenology, reproductive biology and management of trees [14].

Our study also indicates that tree species of Uttar Pradesh belong to 10 native ranges. However, there are anumber of tree species that share more than one native range, species from 10 different native ranges are identified, these are: South America (350 species), North America (39 species), East Asia (04 species), Africa (39 species), Australia (52 species), Tropical Asia (45 species), Pacific (10 species), Europe (12 species), Indian Subcontinent (103 species) and Asia (306 species) (Fig. 2). Data regarding native range and distribution of any plant species is useful for conservation initiatives, as it shows how species are naturally suited and capable of flourishing. In context of tree species, this information is also critical for tracing migratory/spread routes of respective tree species, comprehending and preserving healthy ecosystems, effective land management, afforestation, reforestation efforts, and promoting the sustainability of forests and the diversity of life they uphold [15].

IUCN database was used for evaluation of threat status of the species, 04 species are classified as Endangered (Ficus cupulata, Tecomella undulata,  Tectona grandis,  Pterocarpus santalinus), 05 species is Vulnerable (Cleistanthuscollinus, Dalbergia latifolia, Jacaranda mimosifolia, Santalum album, Saracaasoca), 09 species are Near Threatened (Aegle marmelos, Albizia thompsonii, Dalbergia melanoxylon, Eucalyptus camaldulensis,  Eucalyptus paniculata,  Eucalyptus robusta, Handroanthusimpetiginosus, Swietenia mahagoni, Pterocarpus marsupium), 245 species are under Least Concern category and 16 species are Data Deficient. The remaining species are not mentioned in the IUCN database. The information regarding IUCN status of a particular plant species is very crucial as its knowledge creates awareness and understanding of threats of biodiversity in common people as well as guide researchers, conservators, and local/national/international authorities to formulate strategies and to understand level of effort for its conservation [16].

In conclusion, we hope that the effort of our team in the form of this manuscript will be useful for the researchers, conservators, and policymakers who are continuously devoting their effort for understanding phenology-migratory routes of different tree species, conservation of nature, different aspects of biodiversity and maintenance of healthy ecosystems.

Acknowledgements:

The authors are grateful to The Director, Botanical Survey of India, Kolkata and Head of Office, Central Regional Center Allahabad, for their kind support and for providing necessary facilities during the present compilation work.

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