Here is the historical society sign at the corner of West Calvary and Rice Lake Road.

Yeah. I would guess that they're still talking about 1918 in this postcard. I mean, when I go hiking back of Woodland, I am pretty conscious of the fact that much of what you're seeing (like say, on both sides of Vermilion Road), is still the regrowth from 1918. That's less than a hundred years of growth. An aspen's lifetime is about 80-90 years. The lifetime of a birch is about 150 years, tops. If you walk through these semi-urban forests, you see some white pine and a lot of fairly young red pine. The rest is popple and birch etc. What we see around us, for the most part, is the regrowth from the first and possibly second cuts (logging) and then the fire. Our most serious clearcut logging was right around 1880-1890. Millions and millions of board feet went down the rivers to ships and built Chicago after the fire (and here and ... ) 

So, I wouldn't be too surprised that the devastation the postcard refers to is 1918 (and possible subsequent smaller-scale fires). Think of how few of the trees left after the big clearcuts would have survived that fire (because they left few standing, if any—unlike the modern way of logging--so you had big rotting slash piles and forests of trees not even half way  to full grown. 

To someone traveling here in the 1930s, they'd have been raised on the tales of this area being "The Big Woods"... but at that time, we definitely weren't the big woods. Look at photographs from 1900 here, and you see scalped hillsides with a few scabrous trees. When I stand on top of Gazebo Point near Hartley, I look out on a sea of treetops. A hundred years ago, those trees were saplings.