This is because the nitrogen in the pollutants acts as a fertiliser. However, the root systems do not develop as well as in trees that have to collect their nutrients from a larger area and the trees are more easily blown over. Also, they are short of other vital nutrients and the wood can be very soft making the trees more prone to attacks from insects. These minerals are taken in by the trees causing their growth to suffer. Damaged coniferous trees can be recognised because the extremities of the trees die, especially the crown which is most exposed.
Needles drop and leave the tree looking very thin.
Branches on some trees droop. In most cases acid rain does not kill the tree. It is one more pressure on the tree which becomes stressed and more likely to suffer damage from insects, fungi, frost, wind and drought. Although deciduous trees generally do not suffer as much, research is showing that their growth is also affected. Water courses and lakes Water courses and lakes are affected by the acid rain which falls directly into them and from water which runs into them.