Greenhouse gases are merely one of the significant changes we cause to our environment.
The issue with biomass is the huge land surface it requires to produce the necessary fuel.
But if you want to focus specifically on biomass, I would say: "it depends". You can't answer that question easily. For instance, would you say a biomass plant producing electricity from wood pellets imported from Brazil is carbon-neutral? I think it isn't. When you're looking at biomass, you can't just look at the plant, you need to focus on how its fuel is sourced, what impacts this sourcing activity has, etc.
No; the reason is that this wood is a byproduct of land use change, which is a source of increased carbon emissions [1].
[1]: https://en.wikipedia.org/wiki/Land_use,_land-use_change,_and...
But the carbon cost to manage, process and transport that fuel is not neutral.
Because gasoline for the trucks and coal for the electricity is fossil carbon. Which is not biomass. My point.
If all the energy we consume today for heating, cars, electricity etc would come from biomass/trees then a huge part of our forests would have to be cut down in just a few years time, before they have a chance to grow back.
The cycle keeps running with or without humans doing the emissions part.
So lets focus on the extra carbon that we dug out and inserted into the cycle.