If you add the slight qualifier "there is no anti-tree-planting lobby" then it works... those logging companies will also enthusiastically support planting trees
There's no lobby, but you count me as part of an anti-tree-planting group. There's a specific reason why, and it's because of how it's done. The reason that they plant trees, is to grow specific kinds of trees that are good for logging companies. So they spray areas that are logged with glycosphate to prevent other plants from reclaiming the logged areas, and then plant round-up ready GMO trees in the area. It leads to these massive mono-culture forests that are prime for huge forest fires. The trees they want are fire-promoting trees (like pines), and the trees they don't (like aspen) are fire break species. They then blame the bigger forest fires entirely on climate change.
Trees are not 100% carbon. Logging worsens soil conditions when no effort is made to preserve it. "Just keep planting lol" is not sustainable. Algae sequester carbon better.
What logging does is create an economic incentive to plant the trees and let them grow. The problem with algae is that it doesn't have economic value currently. People dream about turning it into food or biofuels but that's not currently viable.
Although if you were only interested in sequestering carbon (which currently has close to 0 economic incentive) you could grow algae, filter them out of the water, and then pump them deep underground into old gas/oil wells. It's still a lot of energy but possibly more viable than most carbon capture proposals. Over millions of years that algae will probably turn back into coal/oil.
Also, farming algae in natural waterways tends to have its own environmental impacts.