Urban vegetation includes   trees, shrubs and, herbs in public and private lands (parks, streets, backyards) in the landscape dominated by paved surface. Urban vegetation plays a vital role as it moderates micro climate apart from sequestration of green house gases (CO2, etc.) and aid in the percolation of water. World Health Organization recommended minimum green space of 9.5 m2/person) considering the services (oxygen, moderation of micro climate) and goods in the urban environment. Estimates indicate that about 6 tons of carbon is sequestered by 1 hectare forests annually and this accounts to 6 kg/tree/year. Per capita respiratory carbon ranges from 192 to 328 kg/year depending on physiology of humans (525-900 gms/day/person depending on the physiology). This means 32 to 55 trees per person in a region is required to mitigate respiratory CO2 only.

Bengaluru / Greater  Bangalore / Bruhat Bengaluru / Bangalore  (77°37’19.54’’  E  and  12°59’09.76’’  N)  is  the  principal  administrative,  cultural, commercial,  industrial,  and  knowledge  capital  of  the  state  of  Karnataka. Bangalore city population has increased enormously from 6,537,124 (in 2001) to 9,588,910 (in 2011), accounting to  decadal growth of 46.68% . Population density has increased from as 10,732 (in 2001) to 13,392 (in 2011) persons per sq. km.  The vegetation of Bangalore was classified as dry deciduous forest-type under the Terminalia-Anogeissus latifolia-Tectona series. The city enjoyed salubrious climate throughout the year prior to industrialization era.

Land use analysis based on the fusion of Resourcesat-2 MSS data with Cartosat 2  show that the spatial extent of  tree vegetation in Bangalore is  100.02 sq.km.(14.08%).  Spatial extent of vegetation is minimum (less than 1 hectare) in wards such as Chickpete, Shivajinagara, Kempapura agrahara, Padarayanapura, while wards such as  Varthur, Bellandur, Agaram have higher vegetation cover (> 300 hectares). The wards such as Hudi, Aramane nagara and Vasantha pura have higher vegetation density (spatial extent of area under vegetation to the geographical are of a ward) of more than 0.4, while Chickpete, Laggere, Hegganahalli, Hongasandra, Padarayanapura have lower density with less than 0.015. Bangalore has an average vegetation density of 0.14. Mapping of trees based on canopy delineation coupled with field data show that wards such as Vathuru, Bellanduru, Agaram, Aramane nagara have the trees  greater than 40000 trees, while  Chickpete, Padarayanapura, Shivaji nagara, Kempapura Agrahara, Kushal nagara wards have trees less than 100 trees. Based on these, total number of trees in Bangalore is about 14,78,412 trees. Computation of trees per person show that Shivaji nagara, Dayananda nagara, Chickpete, Padarayanapura, Kempapura Agrahara wards  have very less number of trees per person (< 0.002). This highlights that these wards have less than 1 tree for every 500 people. Compared to this, wards such as Bellanduru, Jakkuru, Varthuru, Agaram, Aramane nagara have  trees more than one per person indicating the presence of one tree for every person. Intra city analysis show that major cities such as Gandhinagar, Bangalore, Ahmedabad, Brhihan Mumbai are with spatial extent greater than 400 sq.km.  Gandhinagar has 416 trees for every 100 people followed by Bangalore with 17 trees, Brihan Mumbai with 15 trees and Ahmedabad with 11 trees. Reduced vegetation cover with urbanization has serious implications for the city’s environmental and ecological health. This highlights the city has crossed the threshold of urbanization evident from a range of psychological, social and  health impacts for residents including dramatic increase in recent times of instances such as  higher instances of domestic violence, obesity,  enhanced asthma levels, traffic bottlenecks, road accidents, etc. Overall improvements in human well-being and community vitality necessitate urban planners to maintain at least 33% green cover in the region. In such a case there would be at least 1.15 trees/person in the city.

Keywords: Benagaluru, Bangalore, trees, tree density, vegetation density, trees per person