Newsroom today has an excellent, in-depth article on pine trees as carbon sinks. The TL;DR is that pine is really good at soaking up carbon, but people prefer far-less efficient native forests instead. Which is understandable, but there's two problems: firstly, we've pissed about so long on this problem that we need to soak up carbon really fast; and secondly, that all our tree nurseries are geared for pine and other exotic forest species rather than natives, because that's what commercial forestry uses.
The proposed solution is hybrid forests - using pine as a nursery crop to provide shade and shelter for native seedlings underneath. When the pine dies, you have a native forest waiting to take over. People already do a similar thing with gorse (leave it be and rely on succession to do the rest), and it sounds viable in areas where you can already do that. Though apparently many landowners hate pine enough that they want nothing to do with it - in which case, we'll just see foreign forestry companies buying them out and planting it instead.
One point that needs to be made is that forest sinks aren't a way of avoiding emissions reductions. Yes, you can offset temporarily, but ultimately our emissions are going to have to be reduced to near-zero. Instead, forests are really a mechanism for drawdown: soaking up some of the carbon we've spewed into the atmosphere and locking it away in the biosphere instead. Given the amount we've emitted, we're going to need to plant an awful lot of trees, so we might as well start now.