These modules are designed for use with this modular LED lamp base:
https://www.thingiverse.com/thing:4321472
See here for video: https://youtu.be/ko3FH1WTadw
See here for stable download: https://thangs.com/mythangs/file/40247
The models pictured are printed in spiralized mode using standard white PLA+. To make the lamp brighter, print with clear or coloured translucent filament or cut the bottom off to allow more light up into the tree.
Tree are provided in small or large, straight or bent, plain or with ornaments.
The base in the model pictured is milled out of Eastern Maple, but the base can be printed.
Here are other modules that use the same LED base:
"Out After Dark" https://www.thingiverse.com/thing:4332088
"Among the Ruins" https://www.thingiverse.com/thing:4322049
"Penguins on Ice" https://www.thingiverse.com/thing:4321879
"Rabbits in Forest" https://www.thingiverse.com/thing:4321943