Analysis of socio-environmental impacts of the loss of urban trees and vegetation in Lahore,Pakistan:a review of public perception

Introduction:This paper focused on the process of urbanization in Lahore and its correlation with the loss of urban vegetation and perceived environmental impacts based on local population’s perception through administration of a questionnaire survey.Lahore is known as a city of gardens and green spaces in Pakistan and always possessed rich green character in its long history.For the past few decades due to rapid urbanization,the city has lost its aesthetically important urban vegetation,tress,and greenery.The field studies and remote sensing data revealed that the loss of vegetation has been experienced at an astonishing rate in many union councils of the city.Methods:This study was conceived to probe importance and value of the urban tress and vegetation of Lahore in an environmental context and its general importance for the residents of the city.The objectives were to analyze the role of vegetation in the life of citizens;the specific objective was to reveal the attitudes and responses of city dwellers about loss of urban trees/vegetation and its role in the overall environment,process of urbanization,and maintenance strategies.In the present paper,perception of local people(n=2080)regarding the socio-environmental impacts due to the ongoing process of urbanization and detriments of vegetation loss has been probed through administration of a household questionnaire.The collected data has been tested with respondent’s age,gender,marital status,education,monthly income,and occupation.Results:This study was an attempt to document and explore the change in historical transformation in vegetation and perception of the sample population of Lahore.This perception survey has revealed that urbanization is the major cause of loss of vegetation and has caused a number of perceived environmental problems in the city.Conclusions:The study underlined an analysis of people’s perceptions regarding the loss of trees and vegetation.The perceived socio-environmental findings revealed that the urbanization and population growth are the fundamental reasons for trees/vegetation loss in the city.

Damaging Agents and Tree’s Health Condition in an Urban Forest

Urban trees are subjected to different damaging agents throughout their lifetime. The aims of this study were to identify tree damaging agents, and to obtain a Damage Severity Index (DSI) in order to categorize tree health condition at San Juan de Aragon Park. Each tree was identified at species level in 28 randomly established plots in ten sections of the study area. Up to two types of damage were recorded per tree, based on the FIA (Forest Inventory an Analysis Program) protocol, and a DSI was obtained for each damaged tree considering location of damage, nature of the damaging agent and severity. A total of 753 trees were assessed and 12 species and 27 damaging agents were identified. Cankers, galls, the pepper tree psyllid and the red gum lerp psyllid were the most frequent damaging agents. Australian pine, red gum, Mediterranean cypress, Mexican white cedar, and California pepper were the most affected species. The DSI ranged from 3 to 17 and the average was 7.9. Sections J and H and the species California pepper, Australian pine, and Mexican white cedar presented the highest DSI. The tree population had a moderate health condition, while the aforementioned sections and tree species showed the poorest.

Effects of the urban heat island and climate change on the growth of Khaya senegalensis in Hanoi,Vietnam

Background: Recent projections expect that Vietnam will be affected most severely by climate change with higher temperatures, more precipitation and rising sea levels. Especially increased temperatures will worsen the situations in cities, amplifying the urban heat island effect. Green infrastructures, i.e. urban trees are a common rtool to improve the urban micro-climate for humans. Vital and well growing trees provide greatest benefits such as evaporative cooling, shading, air filtering and carbon storage. However, urban tree growth is often negatively affected by urban growing conditions such as high soil sealing with compacted tree pits providing small growing spaces with limited water, nutrient and oxygen supply, further warm temperatures and high pollution emissions. This study analyzed the growth of urban and rural African mahogany(Khaya senegalensis(Desr.) A. Juss.) trees in the city of Hanoi, Vietnam and the effects of the surrounding climate conditions on tree growth.Results: The results showed that rural African mahogany trees grew better than trees situated in the city center, which is contrary to other results on tree growth of temperate and subtropical cities worldwide. Moreover tree growth was similar regardless of the time of growth. Other results regarding stem growth of African mahogany located in different areas of Hanoi(east, west, north, city center) revealed a better growth in the northern and western outskirts of the city compared to the growth of trees in the city center.Conclusion: African mahogany trees in the urban centers of Hanoi showed a decreased growth compared to rural trees,which was likely induced by a low ground-water level and high pollution rates. In view of climate change and global warming, the decreased tree growth in the city center may also affect tree service provision such as shading and cooling. Those climate mitigation solutions are strongly needed in areas severely affected by climate change and global warming such as Vietnam.

i-Tree Eco Analysis of Landscape Vegetation on Remediated Areas of Oak Ridge National Laboratory

The Oak Ridge National Laboratory (ORNL) is the largest and most diverse energy, research, and development institution within the Department of Energy (DOE) system in the United States. As such, the site endures constant land development that creates rigorous growing conditions for urban vegetation. Natural resource managers at ORNL recognize that trees are an integral component of the landscape and are interested in characterizing the urban forest and their associated ecosystem services benefits. We evaluated the urban forest structure, quantified ecosystem services and benefits, and estimated economic value of resources using i-Tree Eco at ORNL. While this assessment captured over 1100 landscape trees, the ORNL Natural Resources Management for landscape vegetation can be expanded to include unmanaged landscapes, e.g. riparian areas, greenspace, and other vegetative attributes to increase ecosystem services benefits. Assigning a monetary value to urban forest benefits help to inform decisions about urban forest management, ideally on cost-benefit analysis.

Urban Forestry Research in Europe-An Overview

A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or...

A field experimental study on the impact of Acer platanoides,an urban tree invader,on forest ecosystem processes in North America

Background:Invasive species affect community dynamics and ecosystem functions,but the mechanisms of their impacts are poorly understood.Hypotheses on invasion impact range from Superior Competitor to Novel Function,from Enemy Escape to Microbial Mediation.In this study,we examined the effects of an urban tree invader,Acer platanoides(Norway maple,NM),on a mesic deciduous forest in contrast to its native congener Acer rubrum(red maple,RM)with a split-plot design experiment.A total of 720 maple seedlings were transplanted to 72 plots under 24 trees of three canopy types.The three experimental treatments were removal of resource competition at above-and belowground and removal of leaf-litter effect.Soil moisture and nitrogen-related microbial activities were followed for each plot.Results:We found that partial canopy removal increased canopy openness and light transmission to the forest floor,but to a greater extent under NM than under RM trees.NM seedlings were more shade tolerant than RM seedlings in height growth.During the reciprocal transplantation in the mixed forest,biomass accumulation of NM seedlings under RM trees were twice as much as under NM,while that of RM seedlings under NM trees was 23.5%less than under RM.Soil net nitrification and relative nitrification were significantly higher,but mineralization rate was much lower under NM than under RM trees,which would lead to faster N leaching and lower N availability in the soil.Plots with litter removal had significantly higher seedling mortality due to herbivory by the end of 2 years,especially for NM seedlings under NM trees.Trenching enhanced soil water availability but there was no difference among canopy types.Conclusions:Our results demonstrated that invasion of NM not only altered forest canopy structure but also changed herbivory rate for seedlings and N dynamics in the soils.NM seedlings were more shade tolerant under NM canopies than RM seedlings and were more protected by NM litter under NM canopies than under RM canopies.These altered biotic and abiotic environments will likely facilitate further invasion of NM in the forests,hence positive feedbacks,and make it an increasingly serious tree invader in North America.