That looks really awesome! I'm surprised it took you a few days, because for me it'd take a miracle to get it done in a few YEARS, and I'd still have quite a few flaws in it! This is amazing, and by far one of your best works (yet), Dave (not that your others were bad, that is. They're all awesome, this is just one of the best)!
nice dude. i need saw this challenge this morning, i still need to do mine! for a critique, i dont think those trees in the background would ever be that saturated, and trees are usually darker than the grass. try making them closer to the color of your tufts of grass in the foreground.