No, but what can affect them is merging with nearby biomes, and if the Gleam Lake biome ends up really small in an area (which can happen either from having a ton of biomes or Gleam Lake in an area with tons of mountains). The large blocks of gleam that aren’t Gleam Lake usually are the result of it merging with another biome. Gleam Rain can do this too, but doesn’t seem as common. This can be good or bad, sometimes you get too much other material mixed in or a thin layer. If you aren’t wanting to experiment, main thing here is just knowing that a lot of the floating terrain biomes can do this (floating shrapnel, sky pattern are a couple) though usually you’ll still have some regular spheres.
Sounds like the stumps of Island Trees. Can get stumps or hills of wood from this biome, especially from merges. One of my favorite biomes - the wood underground is pretty solid (on the surface the trunks are hollow and rock), and the canopies of the trees are great bean and glow cap farming. Level 6 pick, IIRC, so need a 4 to get it.