There are four variables for your to input:
The northern limit is the current range that you find from the maps.
The maturity to seed is the number of years the tree needs to grow before it can make seeds.
The seed propagation is the distance from the parent tree that the seed can move and be planted.
The warming per 100 years is the number of degrees Fahrenheit that you think the temperature will rise in the next 100 years.
If the blue line crosses the red line the tree species may become endangered.
If the brown line has a negative slope the tree species' range will shrink.