Trees seem to be the solution of the day but, cynically, it seems to be a smokescreen in that some people are promoting this as the solution to climate change. No amount of tree planting is going to solve long term climate change, so it should be seen as one action amongst many. The focus on tree planting shifts the focus away from the action needed to reduce carbon emissions. It's a bit like building an extension to your house whilst the house is on fire. It'll catch up eventually.
"No amount of tree planting..." is a strong statement. Not "we won't do enough", but "No amount..." will work? I find that hard to imagine. Is there a reason you say this?
Two reasons: trees are part of a carbon cycle, most of the carbon returns to the atmosphere eventually, and we don't have an infinite sized planet to keep planting forests at the same rate which we're producing CO2.
New growth forests are good at capturing carbon short term, but established forests aren't as good as the rate of growth is slower and there is more tree decay & decomposition of organic matter releasing C=2. In some places, and more common due to climate change, a forest fire will sweep through a forest and undo all that carbon capture.
If we use trees for fuel it is closing most of the cycle for that carbon, less ancillary fuel use for harvesting, producton & transport, but that doesn't solve the production from other sources. If we use wood for building & materials then the carbon capture is longer, but that's a small fraction of the CO2 capture needed.
Natural forest fires have a fairly minimal impact on old-growth forests and in some cases are even necessary for them to function properly (e.g. some pinecones will only open when burned). The underbrush and younger trees burn off, the older trees are largely unaffected.
What most people don't realize is the trees that exist today are all "new", as in are less than a few hundred years old. The trees that were cut down in the 18th and 19th century are unlike anything you'd see today. Far, far bigger and longer lived, on time-scales that we're really not used to dealing with.
These capture carbon and store it for hundreds of years. When they die they will decay and be recycled back into the forest floor and soil, not necessarily burned off and released as CO2.
Sure, a half-hearted tree-planting effort is not going to solve the problem, but a more ambitious reforestation plan with an emphasis on carbon-sequestering trees instead of those trees intended to be harvested every 20-40 years could make a huge difference.
Well, trees can store a lot of carbon while they're alive. When they die, they release a lot of that back into the atmosphere as they decompose. So, trees are medium-term carbon storage. I expect we'll eventually need to figure out some way to store carbon long-term (for example, put it back in the ground in a way that it'll stay there).
Once the forest is mature, though, it's mostly just storing the carbon, rather than acting as an effective sink. So maybe you need to cut some trees down from time to time, and store that wood somehow where the carbon will be locked up for a long time without taking up valuable land area.
The problem is that we keep pulling carbon out of the ground and introducing it into the ecosystem. If we don't have a corresponding method of removing it from the ecosystem, we'll eventually run out of room for forests that we can use to store it. Some of that happens by natural means, but we'd have a bit more breathing room if we could figure out how to make it happen faster.