In the sweltering heat experienced before and even now, Penangites are now more conscious of the significant value of roadside trees judging from the number of complaints to Sahabat Alam Malaysia (SAM) whenever tree cutting activities are in progress or when a neighbour cuts down a roadside tree.

Complaints ranging from the Municipal Council's ignorance o­n the importance of roadside trees to senseless cutting and chopping of trees are all too common.

In any development project developers are quick to fell trees o­nly to be replaced with dwarf trees and palms which could hardly provide shade .

There is also the question of whether we need to fell and remove old trees to make way for road-widening schemes that o­nly promote an ever increasing volume of traffic? Should our natural heritage be sacrificed to the urban landscape and its infrastructure?

High density development in almost the whole of Penang is turning the Pearl of the Orient into a concrete jungle. In urban areas temperatures are highest due to the felling of trees for both road infrastructures and development schemes.

Temperatures in urban landscapes are now hotter than rural areas, a phenomenon known as an 'urban heat island'.

Urban heat islands are the result of replacement of plants with surfaces such as asphalt, brick, and concrete. These surfaces have a low reflective capacity, so they absorb and store solar energy instead of reflecting it.

The canyon-like structure of cities also reduces heat loss to the sky. The result is that late into the nights, cities are much warmer than their less urban surroundings. The warming of our cities contributes to high pollution levels, and that pollution in turn contributes to the heat island effect.

Higher temperatures speed the chemical reactions that lead to high ozone concentrations, and at night, the pollution lying over a city inhibits heat loss.

Another factor exacerbating the situation is that buildings and industrial development in urban areas continue to crowd out trees, and they are not replaced as they die or are displaced with other trees which hardly provide shade.

The increase in city temperature is also caused by air pollution from the city's industry and transportation which traps latent heat from escaping into the upper atmosphere, thus the increase in temperature.

Unfortunately, the value and importance of trees are often overlooked by municipal councillors, engineers, road planners and contractors who do not have arboricultural training or qualifications, so it comes as no surprise when decisions are made to favour the built environment with disregard for tree care and maintenance.

Thus, city trees are subjected to a very hostile environment such as soil compaction, air pollution, drought and mechanical injury from traffic accidents, vandalism and construction work. Very often the soil around a tree is completely sealed with concrete and other material leading to mechanical injury. Even the non-sealed area of soil around a base is heavily compacted by traffic or pedestrians depriving the tree of aeration and water. An infringement of a tree's rights to a living space.

Reasons for getting rid of trees vary from calls for safety, overhanging boughs in gardens to leaf litter.

However in any situation mature trees should o­nly be pruned to remove dead branches or when the branches are a threat to people's safety and property. Often a whole tree is cut down exposing residents to glare and heat previously filtered by the sun.

State authorities should be concerned in reducing urban temperature not increasing heat. The need to conserve and plant trees is an attractive strategy both for saving money through energy efficiency and for improving the quality of life in urban areas.

In places where there are plenty of trees, much of the solar energy that strikes vegetation is used by the plants for metabolic processes. A plant also uses moisture for controlling its own temperature and then releases the excess, thus cooling the surrounding air.

The usefulness of trees is to be emphasised. Trees have a calming effect o­n people and are a blessing for the city. They play an important role in muffling disturbing noise, act as air pollution filters, release oxygen, attract birds and serve as their habitats, provide shade and act as effective windbreaks.

One of the simplest and cheapest strategies for countering the urban heat island effect is to increase the number of trees and other plants. Vegetation cools directly by shading and indirectly through evapotranspiration, the process by which plants release water vapor.

Perhaps city planners should familiarise themselves with the values and benefits associated with trees. An important part of understanding the status of the urban forest is through proper management such as tree care practices including planting, maintenance, removal; planning regulations and guidelines pertaining to trees and promote conservation of urban trees by focussing attention o­n all trees and not just large heritage trees.

It is important to make decisions that influence the health and performance of trees even before they are planted. The right selection of trees in accordance to the functions they fulfilled and conditions under which they thrive are important to ensure that the right tree is planted in the right place. The point of this is to ensure proper compatibility between trees and planting sites to reduce sidewalk damage and conflicts with overhead utilities to offset tree removal .

There is a need to provide sufficient tree planting to keep pace with urban growth and offset tree removal. It is disheartening to note that even though there is a Tree Preservation Act whereby all street trees are categorised in accordance to their aesthetic and ecological importance, it is hardly enforced.