Jerry's Tree was CaptainSparklez' home in his long-running Survival Minecraft Series, which began in February 2012. It was just an ordinary jungle tree when he found it in episode 2 (February 2012), but he soon made it his home. He built platforms on it that he lived on, and built a mob spawner, as well as many other farms and devices.
In episode 6 (February 2012), he found a baby slime while mining and decided to keep it as a pet. He named the slime Jerry, and kept it in a little pen inside his mine.
In episode 17 (April 2012), he returned to his mine only to discover that Jerry had despawned. He decided to name his home "Jerry's Tree" and built a memorial to Jerry at the very top of the tree.
For his 500th-YouTube video special (June 2012) he asked Pimp My Minecraft to help rebuild his home. They went onto his world, and completely rebuilt Jerry's Tree, building a humongous tree far larger than the tree was before. They rebuilt Jerry's Memorial at the top, in remembrance of Jerry the Slime.
After CaptainSparklez defeated the Ender Dragon in episode 39 (September 2012), he started Season 2 of the series in November 2012, adding the mods Tale of Kingdoms, DivineRPG, Not Enough Items, and TF2 Teleporters. He continued living in Jerry's Tree for the duration of Season 2, which went on for 76 episodes until June 2013.
Once CaptainSparklez had finished Tale of Kingdoms and had pretty much completed DivineRPG (having unlocked all dimensions and defeating all bosses outside Vethea), he started anew a few days later with Season 3 of his Survival Minecraft series, starting a new world with the Aether mod.
In this new world, he MC-Edited Jerry's Tree so that he could continue to live in it. He explored the Aether, and went into a dungeon, where he eventually realized that many features of this mod were unfinished, so it was very difficult for him to progress through the dungeon. He ended the season in July 2013 with a grand total of 9 episodes.
After the Aether debacle, he started over yet again the next day, MC-Editing Jerry's Tree into a new world, and he began Season 4, in which he installed the Hexxit modpack. This season continued for 69 episodes, until he ended it in January of 2014.
In February 2014, he began Season 5 of this series, titled Ultra-Modded Survival. This season was named as such because his new world ran 61 different mods. For the third time, he started a new world and MC-Edited Jerry's Tree into it to live in. He ended the season, which was the final (and longest) season of the series, with episode 137 in October 2015.
However, this was not the last time he would see Jerry's Tree. Back in August 2015, CaptainSparklez had started a series called Jerry's Laboratory. In this series, he created a copy of Jerry's Tree and put it into a new world, in which he had BlockWorks build an enormous laboratory under the tree, for CaptainSparklez to test out various different mods. CaptainSparklez has sporadically released episodes of this series ever since.