No, by this logic one just needs to take into account how long is required before you consider something "sequestration." Ocean sediment, for example, stays down there for hundreds of millions of years before subduction and vulcanism might bring the carbon back up. So it's not permanent but it's certainly permanent enough.
Trees last for a couple of decades. And once a forest is established they turn over continuously, so the forest as a whole emits as much carbon as it takes in. As we see here with the boreal forests in the article, the carbon comes back out into the atmosphere quite easily. I personally wouldn't consider it a very good "sequestration" method.
If you really want to use trees for carbon sequestration, a good approach might be setting up big tree farms and then sinking the harvested wood into anoxic lakes. That'd take the carbon out of circulation for a long enough time that future generations can figure out what to do with it afterward.