Thank you for sharing. Like yourself I too have edited the vegetation files using 100’s of different variations to determine the best representation of trees. Although there are certain sets of settings which do make a pleasing visual difference, the problem is somewhat more complex as CptLucky8 has already mentioned.
Terrain LOD affects the detail visible on the terrain, although there is a slight draw distance ring increase in Terrain LOD, the actual ring LOD from the aircraft position is not directly affected. The same principle works with Object LOD, higher settings do not render objects further away from the aircraft, all it does is render the objects within the ring LOD with sharper details. As previously mentioned… again by CptLucky8 things start to get really weird when reducing the Terrain LOD to 100 or less, more trees are rendered further away from the aircraft, however the LOD ring (trees specific) close to the aircraft position is sometimes reduced.
Here is a simple breakdown of how the LOD settings actually work. Picture yourself on a giant sheet of paper (flat), the sheet of paper is populated with 1000 black squares (representing objects) and 1000 black circles (representing trees), there are also feint lines on the paper (horizontal and vertical) representing the Terrain. While flat on the piece of paper, you can see the squares,circles and lines nearest to you in all it’s glory. You begin to start ascending, and the patterns start becoming smaller, there’s still the same number of squares (1000) and still the same number of circles (1000), also there are still the same number of lines. Terrain LOD depicts how sharp those lines on the paper will be while ascending, the number of lines do not increase, only the quality of what’s already present. Objects LOD works exactly the same way, the quality of whats already present is more definable from altitude.
Draw distance (the setting we do not have access to yet) will determine how many sheets of paper we can add to our original one. Trees, Buildings and Bushes settings (within the sim) do have an effect on the LOD within the LOD ring, however there are dependencies within the code that makes the behavior of populating these objects somewhat confusing.