What is the horizontal scale of your graph? How many years does it show?
The x axis is years counting by 20 years and from 1960 to 2000.

What is the vertical axis showing? What are the units? What is the total range shown?
The y axis shows temperature, and the temperature ranges from -0.6 to 0.6 and it counts by 0.2 per a unit.

Can you tell from the picture's host page where the data came from? If so, where?
They don't specifically say where the data came from.

Text book thing

Where there is a lot of water/rain their are large amounts of tree and grass growth. When there is lower amounts of water there isn't much or none tree growth and there is grass.

This a Land Slide. These Land Slides can be caused by loose soil and heavy rain fall and other reasons.