Hyper carbon accumulator(s) for backyards

I am curious, what people could do with a small piece of land like their home backyard (say originally it is a regular lawn smaller than 20m^2, in temperate continental climate (so pretty harsh)) to help fight climate change.

Intuitively, we might think fast-growing trees are the best carbon accumulator (e.g. hybrid poplar is a famous one). Wood is nonetheless very stable carbon but it may be an incomplete picture if we focus on the aboveground growth metrics only. As a matter of fact, most stable soil carbon as recent research has shown is root-derived (dead root as well as root exudates)[1][2][3]. Other things like mycorrhizae and dispersing litter also come into play which results in a larger radius of impact on soil carbon. Also, the backyard is preferably minimally managed with no synthetic products needed (which also come with its own carbon footprint).

I would be glad if someone can shed some light on this complicated matter. Answers with scientific evidence and an estimated amount of carbon sequestered (say per year) will be very appreciated 🙂

References:

[1]Sokol, Noah W., et al. “Evidence for the primacy of living root inputs, not root or shoot litter, in forming soil organic carbon.” New Phytologist 221.1 (2019): 233-246.

[2]Lange, Markus, et al. “Plant diversity increases soil microbial activity and soil carbon storage.” Nature communications 6 (2015): 6707.

[3]Treseder, Kathleen K., and Sandra R. Holden. “Fungal carbon sequestration.” Science 339.6127 (2013): 1528-1529.