It's hard to place an accurate count on the number of trees we lose over a span of time because of the size of the number. Easier to track the loss of areas designated as forests since that highlights the biggest change, usually from nearly 100% of the surface area covered by trees to nearly 0%.
The number of trees in a forested acre obviously varies wildly (from about 200 to well over 1,000 per acre), but let's use 500 to start. 500 trees per acre would equal 44 billion trees lost over the 5 year period. So, to replace them, we'd simply need every man, woman and child on the face of the earth to plant about 7 trees.
I think it's a pretty safe assumption that hasn't happened.