How coal was formed
Regarding coal, from trees, it's not simply a question of the area whether it was a continent-size landmass, but more of the temporal side of things -- how long a time period the land was covered.
Coal was laid down from plant matter during the Carboniferous period, which lasted 60 million (60,000,000) years. For most of that time the micro-organisms that existed were unable to break down the lignin which made up 70% of the plant matter. Effectively the trees didn't rot, they fell down, and more trees grew on top, then died and fell down and more trees grew on top, for millions of years. The carboniferous period ended when the microorganisms evolved the ability to consume the lignin and the coal laying stopped.
Three million generations of trees
So supposing it takes twenty years for 'a tree' to reach maturity, the carboniferous period is three million generations of trees. 'Tree' is a little inaccurate compared to what we currently think of as a tree. The plants were effectively a really tall moss, and it was 80% 'bark' compared to modern trees that are about 10% bark.
All land on earth
During the carboniferous period most of the land on planet was covered with trees, Africa, Asia, the Americas. But to somehow recreate all the coal, you need at least twenty years for a tree to grow, and because there were three million generations, you need three million times the amount of land available on earth's land masses.
Suppose we drained the oceans to create more land for more trees, then you'd only need one million earth's worth of land.
How many trees, how many earths?
Currently there are around three trillion tress on earth -- it's not unreasonable to think that during the carboniferous period when there was nothing else happening, there would be maybe double that, six trillion trees at any moment. Over a 60,000,000 year period, that would be a total of eighteen quintillion trees (eighteen with eighteen zeros after it).
My point is, to recreate the coal that we've consumed alone, ignoring the oil and gas, it's not a matter of planting a few trees, its more a case of planting quintillions of trees on hundreds of thousands of planets. 18 quintillion trees at a rate of 3 trillion per planet requires 6 million planets.
Even if my sums are a few zeros out, its a mind-boggling number of trees and amount of land.
What about the coal we've already used?
In terms of coal that we have already burnt, the World Coal Association figures estimate that the proven coal reserves left in the ground are enough to last another 150 years at current rates -- this is the coal that is easy to dig up with current mining technology. There might be vast quantities of coal located in inaccessible locations, like the bottom of the sea, or spread out too thinly to be cost-effective to mine. This isn't included in the proven reserves figure.
Looking at the Global Fossil Fuel consumption graph in the question, we could estimate that historic coal usage is about 75 year's worth at current consumption rate. At current usage rates, the sixty million years of laying down coal gave us around 225 years of coal that is economically accessible. We're roughly a third of the way through that.
From the earlier calculations, that's three quintillion trees spread out over only two million earth-sized landmasses.