Managing Air Pollution through Urban Forestry
Dr. Banarsi Lal
Every year 21st of March is celebrated as the World Forestry Day or International Day of Forests to create the awareness about the values, significance and contributions of forests to balance the life cycle on the Earth. This day was established in 1971 at the 23rd General Assembly of the European Confederation of Agriculture. The theme for 2023 is “Forests and Health”. Forests purify the water, clean the air, capture carbon to fight the climate change, provide the food and life-saving medicines etc. Urban areas are characterized by high population densities and a network of non-natural and built-up infrastructure. High material consumption and per-capita energy and large resource inputs have increased pollution levels in urban areas. The urban areas have been expanding exponentially by encroaching the surrounding agricultural lands and forests from the last few decades. Urban areas harbour a variety of habitats such as water-bodies, parks, gardens, forests etc. We observe that urban areas have old monuments and old trees. Now-a-days our cities have millions of vehicles, ever expanding roads and spewing out immense pollution. People are migrating from rural areas to the urban areas. These rural people migrate to the cities in search of employment and finally want to settle down in the cities. Urban areas have their own limitations as they too have limited resources. With the increasing urbanization and demand for more houses, transportation etc. does urban forestry today stand a chance? The answer may be yes. With the increase in population the demand for wood has also been increased resulting in the fast degeneration of forests and villages woodlots. Presently India has only 11% of the land area under close forest cover. The recorded forest area of Jammu and Kashmir is 20230 Sq. Kms, which is around 19.95% of the geographical area of J&K. Forests are largely distributed in Kashmir valley and Jammu region whereas Ladakh region is devoid of forest vegetation as the region is a cold desert. There can be severe environmental crisis as we cut more trees than we plant every year. Although barren lands are mostly in rural areas but we have a better scope for planting trees in urban areas. Our urban areas need more natural vegetation to check the increasing environmental pollution by purifying the air and improve our microclimate.
In cities pollution is very high due to emission of harmful gases produced by the automobiles, factories, sewage etc. The towering buildings in the cities prevent the free circulation of air, absorb a lot of heat and thus increase the atmospheric temperature. Noise pollution affects the peaceful living in the cities and accelerates the sickness among the people. The pollution in cities can be controlled by planting trees in urban areas as the greenery in the cities helps to sustain natural ecosystem and acts as buffer zones against the pollution. These green areas can also provide habitats for a variety of animals and birds and act as rest places for the hectic life styles of urban people. Urban forests provide environmental health and economic benefits to cities. Urban forestry helps to improve the air quality by absorbing pollutants such as ozone, nitrogen dioxide, ammonia and particulate matter as well as performing carbon sequestration. Tree planting in urban areas is easy because of protection of livestock, availability of water, awareness among the literates’ people etc. Water plays the critical role for the trees growth right from planting. Roof top water harvesting, proper water management and recycling of water including that of utilization of sewage and effluents and other untapped sources can be recommended for growing the trees in urban areas.
Different trees species can be recommended according to the needs of the people. If a river flows through the city then the ecological and land scape value of the river need to be studied and analyzed.
The River Front Development along with appropriate tree species add to the beauty and health of the cities. Selection of tree species for industrial areas is dependent on the nature of industry.
It is necessary to select tall evergreen trees so as to reduce the wind velocity around the chemical factories. Adaptability of tree species to hazardous gases and particulates should be the primary criterion followed by the tolerance of effluent water. Species like Neem, Eucalyptus, Mulberry, Guava, Jamun, Ber and Bel can bear Sulphur Dioxide toxicity. In areas having fluoride pollution tree species such as Cashew, Amaltas Casurina, Peepal, Banyan and Jackfruit can be grown. In Cement factories and thermal power plants areas trees like Peepal, Banyan, Neem, tamarind, Pride of India, Oak, Arjun, Teak etc. can be grown. In areas where there is emission of Carbon Dioxide and smoke trees such as Bougainvillea, Shishum, Drumstick, Ashok and Neem can be grown. When pollution is not a serious concern in the area then selection of trees can be done on the basis of rate of growth, utility and flowering habits. People generally visit parks and other recreational sites to relax. The trees having spreading branches with colourful flowers are preferred for such areas. Trees such as Cassias, Bottle brush, Gulmohar, Putravanti, Banyan and most of ornamental trees can be selected for parks.
Trees in parks should be planted at a wider distance and maintained with proper training and pruning. Medicinal plants help to cure the common ailments but unfortunately they are vanishing fastly. There is need to create awareness among the people about the scientific use of medicinal plants and to conserve them to make use of Ayurveda popular.
Medicinal plants such as Aonla, Asparagus, Cinnamon, Neem, Jamun, Pomegranate, Tamarind etc. can be grown in the herbal gardens. For planting along the roads, the tree species should grow straight with medium canopy. Hardy, evergreen, deep rooted, flowering trees instead of fruit and other valuable species should be preferred. Tree species such as Coral tree, Protea, Plumeria, Raintree and Narra are preferred in these areas.
Strong and deep-rooted trees should be preferred in these areas so that they can be protected from fast winds. Many times we observe that trees alongside the roads are uprooted because of fast winds. Proper planning is necessary to facilitate water infiltration around the trees. Fruit trees such as Mango, Sapota, Lemon, Ber, Fig, Apple, Papaya, Guava etc. are preferred in residential premises. Trees such as Bottle brush, Bakul, Champaka, Exorta night Jessamine etc. can beautify our surroundings. Promotion of fruit trees cultivation can also motivate the people to plant more trees and take proper care. Recommended doses of insecticides- pesticides and fertilizers can be used for the utmost care of trees. In urban areas we generally grow trees and plants in our houses or institutions but now-a-days this is not necessary that we will find open spaces for the plantation in these areas. Multistoried buildings and housing complexes have reduced greenery in the urban areas as apartment complexes do not always offer space to grow trees. We should not despair over this matter and need to find solutions.
Now concept of urban agriculture has been emerged through which we can use our roofs and balconies of our buildings for plantation. We can use pots, old discarded buckets, drums, trays etc. for plantation at the roofs of our residential buildings. Besides ornamental plants, vegetables can also be grown at our rooftops. For a good rooftop garden we must waterproof the place and should have proper drainage systems. If we do not water proof the place although our plants may not suffer it may harm our buildings. Seepage can occur in walls which further can damage the buildings. The water on the rooftop should not stagnate at one place and it should have suitable outlets. Many people in the urban areas are often keen to plant trees at their homes but they don’t get the proper guidelines and planting material. There is need to make the eco-clubs who can encourage the people in planting trees.
They can seek the technical guidelines from the agricultural universities, agricultural institutions and concerned department. Print media and television too can play an important role for creating awareness on trees plantations in the urban areas and guide them on the significance of forests. The NGOs and Municipal Corporations can also help to motivate the urban people in this direction.
(The writer is Sr. Scientist & Head, KVK Reasi, SKUAST-J).