Polux tree

Polux trees are a type of tree that grows within polluted environments. The trees themselves slowly absorb pollution from the surrounding environment in an area similar to a pollution pump (7 tile wide circle), Unlike pollution pumps, polux trees do not generate any toxic wastepacks after absorbing the surrounding pollution. This makes them a safer way to remove pollution.

Growing

Like the gauranlen tree, the polux tree does not naturally occur in any ecology. It naturally appears on maps with pollution, and can be spawned by the "polux tree" event,

Every 15 days, the current pollution level and current tree population are checked. If the current amount of trees are below the assigned value, a tree may be spawned.^[Chance?] These numbers also determine the amount of starting trees in your colony.

No pollution (0-25%): 0 polux trees
Light pollution (25%-50%): 0 polux trees
Moderate pollution (50%-75%): 1 polux tree
Extreme pollution = (75%-100%): 3 polux trees

Polux trees never spawn within 16 tiles of each other.

Polux seeds can also be bought from traders or obtained from quest rewards.^{[Other ways?]}

Summary

Cleans 1 tile of pollution every 25,000 ticks (10 in-game hours).
Needs 150,000 ticks (2.5 in-game days) to clean 1 deteriorated Toxic wastepack (6 tiles).
Is only 20% as fast as a Wastepack atomizer.

Polux trees are considered "super", meaning that pawns with the Trees: Desired precept will receive the "amazing tree" thought after seeing one. Unlike the anima and gauranlen trees, polux trees will still be eaten by thrumbos. All trees can also be eaten by alphabeavers. They are immune to blight.

They technically take damage from toxic spewers and toxic fallout, but regenerate faster than they take damage

Analysis

The easiest way to use polux trees is to plant them nearby, and leave toxic wastepacks in a stockpile zone next the tree. Wastepacks outdoors deteriorate into pollution every 8 days assuming no rain or cold temperatures, creating 6 tiles of pollution.

In 8 days, a polux tree cleans 19.2 tiles. Meaning that a single polux tree can have a stockpile of 3.2 stacks of wastepacks deteriorating without being overwhelmed. However, this assumes that no rain ever increases the deteriorating rate of the packs. To avoid this, consider placing the stockpile next to a natural rock face to act as a support for a roof to cover the stockpile.

Polux seeds are rarely worth buying. This is due to the combination of their high cost, the tree's relatively low waste-clearing speed, and the fact that low amounts of pollution do not have much impact on your colony. As long as the pollution is physically far away, the only negatives of it are wastepack infestations and acidic smog. Polux trees do not stop infestations, as they occur on wastepack destruction, not pollution in general. Meanwhile, acidic smog can be mitigated almost entirely by using sun lamp greenhouses and non-solar energy. Even then, at only 10% or so pollution (200 wastepacks), smog is a rare event.

A polux tree can clean a bit more than 1 toxifier generator's worth of waste, allowing for a form of clean energy. The tree cannot be placed near the generator, making you use a pollution pump and have colonists haul it to the tree. However, clean energy should be compared to 1. leaving wastepacks far from your colony and buying the polux seeds later, or 2. freezing the wastepacks. If you have no better use for silver, then you might as well buy the trees.