Tree Upgrades

The Evolution Tree (also referred to as "Tree Upgrades" or "Skill Tree") is a major feature exclusive to to Scrap Clicker 2 and is unlocked at x40 Stars. At first, only 5 upgrades are unlocked and additional upgrades are unlocked every x5 Stars until x130 Stars and then every x10 and later x25 Stars or more, up to every x250 stars. Upgrades are purchased with Golden Scrap, Fragments, Magnets, Steel Beams, Wrenches and Mastery Tokens.

x45 Stars

 * The Scrap boost upgrade costed 250 Steel Beams until 9.5, where it was changed to 200.

x75 Stars

 * Note: The third tree upgrade made Steel Beams fall 25% slower prior to update 11.0.

x225 Stars
Note that the last upgrade (About Merge levels) was not added for a long time: Until 7.1.

x525 Stars & More
Note: Upgrades which will come soon are indicated with the symbol to the right

Trivia

 * The cost of all upgrades available through x1000 Stars is 94,150 Fragments, 5,554,000 Magnets, 62,18B Golden Scrap, 9,775 Steel Beams and 710,354,825 Wrenches. (outdated)
 * The Million Merge Boost upgrade used to say "Get a x1.05 Magnet Boost every 1 Million Merges" and it also had that effect before version 8.4.
 * The Team Map and Quests are unlocked without the Skill Tree.
 * There used to be two upgrades that increase the max. level of Doubled Barrel by +25 each, at x600 and x1500. In update 11.0, the x1500 upgrade was replaced with unlocking XP and the first upgrade was increased to +50. In 11.1, that upgrade was moved from x1500 to x1400, to make space for a new upgrade at x1600.
 * The compact barrel view unlocked by the x550 star upgrade looks like this: