Struck Log

In swamps and oak groves, there are a few Struck Trees.

These trees do not drop saplings.

When ignited while exposed to sky, it will consume itself and summon lightning.

First, you need a medium that connects with nature.

You will need to find Struck Trees and gather Struck Log to summon lightning.

Strike lapis lazuli with lightning to obtain nature crystals.

Once you have the nature crystal, you can craft a wand and use crystals for block spell casting.