Tree spikes = something is overloading FSX. Solution: turn something down. It could be autogen; or, with this scenery, it could be the special effects.
Mark, I wonder if, in the next version, effects could be tied to the scenery slider?
The effect is most likely linked to the autogen slider and the graphic card. I was able to produce a similar - but transient - effect on my Nvidia 9600 GTO card. It only showed when panning around the aircraft in flight. Turning the autogen down, as suggested, should be the remedy (or better, get a new graphic card). I think this is a texture problem, induced by not enough RAM on the gfx card.
The scenery effects can not be tied to a FSX slider (at least AFAIK), because they are fixed, static elements in the scenery. The only scenery objects you can control with sliders are autogen objects and AI.
Sorry guys, the Solomon update is still cooking. Had a bit of a hiatus for a few weeks because of r/l obligations.
Cheers,
Mark