This is a great question! It's true that trees produce a lot of oxygen during the growing season, but they aren't the only source of oxygen in the world. Here's where oxygen comes from during winter:

* Algae in the Oceans: Tiny, microscopic algae in the ocean produce a huge amount of oxygen through photosynthesis. These algae continue to photosynthesize even in winter.

* Other Plants: While trees lose their leaves, many other plants remain green year-round and continue to produce oxygen, like evergreen trees, shrubs, and grasses.

* The Atmosphere: The Earth's atmosphere contains a large reserve of oxygen that isn't dependent on plants. Oxygen doesn't simply disappear when plants stop photosynthesizing.

So, even though trees are resting during winter, there are still plenty of other sources of oxygen to keep us breathing!