Reviews of numerous individual woody plant experiments reveal a mean growth enhancement on the order of 50% for an approximate doubling of the air’s CO₂ content (i.e., a 300 ppm rise).

This photo illustrates this phenomenon for pine trees grown in normal air and air enriched with an extra 150, 300 and 450 ppm of CO₂.  Taken some 35 years ago, Dr. Sherwood Idso, demonstrating the beneficial effects of atmospheric CO₂ enrichment on plant growth.

Source:

Craig Idso, Increased Plant Productivity: The First Key Benefit of Atmospheric CO2 Enrichment, Master Resource(Apr. 21, 2022). https://www.masterresource.org/carbon-dioxide/increased-plant-productivity-the-first-key-benefit-of-atmospheric-co2-enrichment/