Crushed basalt helps trees grow.

https://youtu.be/3toYxpP_S2w?is=SFLv3cGYLMCtVCiU

@1:49 Crushed basalt encourages 85% more growth and 27% more carbon sequestered in 4 years. 

Why? 

Crushed volcanic basalt slowly dissolves in soil water, releasing vital trace elements like magnesium, calcium, potassium, and iron over several years. - ref

This also supports soil bacteria and fungi, which build a healthier living network around tree roots.

Luckily, it's getting a boost from companies needing to pay for carbon offset, like Microsoft. And a large-scale project is underway in Brazil.