IMPACTS OF GLOBAL AND LOCAL FACTORS ON VEGETATION
Temperature – a global factor
This is the main factor affecting plant growth. It decreases as you move away from the equator.
In the tropics, rays are high in the sky for the whole year and so are concentrated on a smaller area. This provides a lot of heat and light so plants grow very well and there is general dense vegetation.
In the poles, suns rays are less concentrated and are spread over a wider area meaning lack of heat and light so less plant growth.
The amount of water will of course also affect what can grow. Precipitation is more likely in places where air masses converge and air rises. The two largest areas of year round rain are the equator and mid latitudes where there are lots of forests as a lot can grow.
In polar and desert areas air masses do not meet so there is little rainfall.