Which Tree Produces the Most Oxygen?

Oxygen production depends primarily on total leaf area and photosynthetic rate. Large deciduous trees with dense canopies generally produce the most oxygen per individual because they have enormous total leaf area. A mature oak (Quercus) produces roughly 100 kg of oxygen per year, a beech about 90-120 kg, and a large maple about 100 kg. Among the champions are: Douglas fir and Sitka spruce (large conifers with year-round photosynthesis), tropical trees in rainforests (where growth rates and leaf area are maximised), and fast-growing species like poplars, willows, and eucalyptus (which compensate for smaller size with rapid growth). However, most oxygen production on Earth comes not from trees but from marine phytoplankton — microscopic ocean plants produce an estimated 50-70% of the world oxygen through photosynthesis. The common claim that the Amazon rainforest is the "lungs of the Earth" is somewhat misleading: the forest consumes most of the oxygen it produces through respiration.