I reckon that trees around or near any building enhances our visual perception of the urban environment. More than this, they also provide an invaluable means of protecting us from some of the pollution we put into the air. Particulates get trapped by the leaves and are then washed off to ground level by rain. And, of course, they absorb carbon dioxide provide us with oxygen.
Trees on the street in front of your house can make a significant difference to the quality of air you breath inside your home.
The trees in the first photo will not make a significant difference to the air that the inhabitants of the new buildings near Park Tawe in Swansea because, as can be seen from the depth of field in the image, the trees are not all that close to the buildings. The trees around BT’s tower block will be more effective in that respect.
City planners and architects should to take all the benefits that trees can bring into consideration when designing any and all new urban developments.