Trees add beauty to the world we live in. They contribute eye-catching colours to our surroundings; different shades of greenery found in leaves, in flowering trees, and sometimes even the bark of trees, add colour and contrast all around us. They create a peaceful and an aesthetically pleasant environment.Trees do not just have a visual quality; trees also enhance the environment in less obvious ways. Since the beginning of time, trees have furnished the world with two essentials of life: food and shelter. They have supported us and sustained life throughout our existence. They contribute to our environment by providing oxygen, improving air quality, preserving soil, supporting wildlife and balancing nature.Further, trees regulate the atmosphere. During the process of photosynthesis, trees inhale carbon dioxide and exhale oxygen that we breathe. According to the United States Department of Agriculture, “One acre of forest absorb six tonnes of carbon dioxide and put out four tons of oxygen. This is enough to meet the annual needs of 18 people.”In addition, trees lower the air temperature and reduce heat intensity of the greenhouse effect and global warming by maintaining low levels of carbon dioxide.Trees are considered the lungs of earth as they purify the air by removing dust particles and other pollutants such as carbon monoxide, ammonia, sulfur dioxide and oxides of nitrogen. That gives fresh strength to the biotic factors of the ecosystem. In a similar way, they absorb and filter radiant energy of the sun, keeping things cool in the summer.In addition to influencing the force of wind and rain, trees shield us from downfall of rain, hail and other precipitations. Trees also prevent soil erosion, especially on hillsides and slopes. Roots of trees help in holding the top layer of soil. They do not allow natural disasters to carry away rich soil.Many herbivores like giraffes, goats, elephants and others eat leaves for nourishment. Animals eat many of the seasonal fruits that we enjoy. This process helps in dispersal of seeds. Hundreds of living creatures, such as bees, urban birds and squirrels, make trees their home.