1. Spatial analysis of Urban Forests & green spaces of Mega
City of Karachi using GIS Techniques.
INTRODUCTION
An urban forest is a population of trees and their associated organisms situated in or around a
human settlement whether it be a City, town and community. Previous research has shown that
urban forests not only positively impact the environment, but also the physiological and
psychological well beings of individuals who partake in recreational activities (Urban Forestry
South Expo 2004).
Urban forests are living utility, the same as road, water systems and other necessities of an
urban environment .They need to be preserved, protected and enhanced so that they can
continue to contribute to the provision of an excellent quality of life in the community (MVH
Associates et.al 2001).Unfortunately, the trees and green spaces in the mega city of Karachi
are not being scientifically managed, and are under considerable environmental stress. Karachi
being the largest city of Pakistan is faced with many environmental issues which need to be
understood and resolved.
All trees have varying risk of failure due to external agents like weather and diseases. On the
extremes, trees as low in the risk for failure can fail during extreme windstorm, while highly
defective trees and parts can fail during calm days. Tree managers have the responsibility to
create and maintain a safe and useful urban forest for their constituents. Modern techniques like
use of GIS and remote sensing can be used to minimize the risk of damage to property and
personal injury associated with tree failure.
The focus of this study is to analyze the growing condition of trees and green spaces in Karachi
city using spatial analyst tool of ArcGIS. Trees and green spaces in urban centers do provide
all the tangible and intangible benefits but they carry some risks too, which sometimes
overweight their benefits.
Hence, the said study is going to spatially analyze and explain the procedures in urban tree
management and green spaces by finding out suitable urban sites for pocket planting ,
creation of new green spaces & corridors and conservation and proper management of old
ones under the aegis of GIS. It also aims at the Assessment of risk associated with old,
decayed and diseased trees growing in urban city area which otherwise may fall down on public
or private property resulting in Law suits and pin point hazardous trees for immediate removal to
ensure public safety.
Landscape mangers can use GIS to analyze trees and their proximity to roads, sidewalks and
utility lines. In addition to showing the number of trees in a given area, GIS maps can show the
distribution of trees threatened by disease or the locations of certain tree species or trees to be
removed so that contractors can get to construction sites. GIS efficiently records composition
and structure, therefore making the decision process for management easier. Through careful
tree inventory, foresters can maximize the benefits and minimize the costs of trees in an urban
area.

2. STUDY OBJECTIVES
The specific objectives of this study are following:
1 .To develop a geo database of trees and green spaces and model the conditions of urban
trees and green spaces.
2 . To determine , evaluate and analyze the level of risk for failure associated with
trees.
3. To find new suitable site for tree pocket planting ,Conservation of old ones and
establishment of new green spaces and corridors.
4. To properly manage urban forests and green spaces under the domain of GIS.
METHODS TO BE USED
Tree data collection and Surveying of existing green spaces shall be conducted on site.
High resolution satellite imagery of city of Karachi shall be obtained and the existing green
spaces shall be digitized and georefrenced. Base map of city of Karachi shall be created and
brought into GIS. GPS is very accurate way to map tree locations. A GPS shall be used to map
trees location and shall be laid on base map of Karachi. Associated spatial data and attribute
data of roads, buildings sidewalks, neighborhood ,water lines ,communication lines etc. shall be
created and georefrenced and merged with tree data layers to understand patterns of features.
It shall help reveal where they are concentrated and where are they scattered and centered.
Having spatially joined the different data layers, the relationships between features shall be
understood and analyzed. The tree attribute data and green spaces attribute data shall be
recorded and geodatabase shall be created in ArcGIS 10.1.
New sites for tree pocket plantings and establishing green spaces shall be created using Model
builder providing different parameters and variables , and old ones shall be identified using
spatial analysis tool embedded in ArcGIS 10.1 suit.
Finally, Integrating GIS technology with tree and green space management program shall be
accomplished for the city of Karachi providing functionalities of Visualization of our green lungs
their proper planning and spatial analysis of our green spaces.
SIGNIFICNCE OF RESEARCH
Trees in urban setting are often taken for granted. Most people are not aware of the many
benefits that urban trees and green spaces provide. These trees are an essential element in
the physical, economic, visual and the psychological well being of our urban centers. Despite
clear evidence that urban forests are an excellent source of aesthetic and functional value,
ineffective management and neglect can lead to a preventable damage to life and property
Further external factors, such as weather and wildlife, take a heavy toll on the health of trees
and further separate an urban community from the benefits of a natural setting. This study on
Spatial analysis of Urban Forests & green spaces of Mega City of Karachi using GIS
Techniques is going to be a pleasant addition to the existing literature on tree management
Since study of this kind and magnitude has never been undertaken before. Hence, the said
study is going to serve dual purpose ensuring the beauty of our green spaces on one hand and
public safety on other.