# Token Rewards: O2

O2 (Oxygen) is the secondary token of the Project Forest ecosystem and acts as the utility token for the project. Tree NFTs and bigger forests generate O2 on a regular basis as long as they are watered.&#x20;

Players can earn O2 in Project Forest through trees, as they produce oxygen, with the rate varying from tree to tree. O2 is used to purchase resources from the Consumables Shop and perform numerous actions in the Forest that help to grow and upgrade the level of their Tree NFTs. &#x20;

Primarily, O2 is used to unlock additional soil pits, purchase Water and Fertilizer, and Excavate a soil pit. More features and uses of O2 will be unlocked as the project progresses.

The initial capacity of O2 is zero, and its total capacity keeps increasing with every tree planted. When the total capacity is reached by collecting O2 tokens released by the Tree NFTs in Project Forest, the excess is lost and you cannot store any further oxygen.

O2 production depends on the type and grade of a tree. Depending on the type, trees of different qualities produce different amounts of O2 at different tree ages. O2 generation is at its highest when a tree reaches tree level 30.

Tree NFTs go in soil pits in Project Forest. Initially, there are five soil pits in the game, and new soil pits will open for players as the game development progresses. Players can purchase these soil pits using O2 and LEAF tokens, although they will have to wait for some time to claim their soil pits. Each player can have a maximum of 50 soil pits, and each will have a storage limit.&#x20;
