I understand about the step filter and it does not help. I am also curious about the bitmap format.. I try both jpg and bmp.. am I missing something.. I can reproduce the problem with following steps.. 1. Create a sceen with single slighly flat terrain with camera near the middle ( I am using default terrain, just lowered in hight ). 2. Load the above image as mapped picture. 3. Change to ecosystem and add "Summer Cherry Tree" 4. select variable density and edit the function 5. Add the image above as texture map on density 6. Add step filter 7. Populate ecosystem and render. I don't always get the same results but its close. I try it with a uniform height terrain and similar results. Oddly enougt a reset terrain produce no results.