The "arguments" that humans aren't causing this range from laughable to extensively contradicted by evidence.

And we have to get this right because the scale of the problem is well beyond what we can escape by "planting a tree".

A mature tree sequesters, very roughly, about 20 kg of carbon per year. Of course it varies extremely widely by species, latitude, etc. etc..

Humans emit about 38,000,000,000,000 excess kg of CO2 per year.

So, no, don't just plant a tree. Plant a tree every other day. Make sure you keep it alive until we stop releasing carbon. And make sure everyone else on the planet does likewise. And then we will only be falling behind about 1/5th as fast as we are now.