3D Tree Rogue Browser Extension
3D Tree is the name of a rogue browser extension that functions as a browser hijacker and makes undesirable changes to your browser.
Upon installing the extension, your home page and new tab will be replaced. Additionally, the default search engine that your browser uses, the engine used when you type your search query into a blank tab's address bar, will be swapped out to search dot 3dtree dot net. This is a fake search engine that cannot produce its own results. Instead, it will spit out a Bing search results page for your respective query. However, you cannot know how your search query is bounced and whether or not it's not recorded and stored somewhere.
Similar behavior is usually the domain of apps and extensions that are classified as browser hijackers. This means the extension makes changes to your browser and its settings that are generally considered undesirable.
The extension is not distributed through the Chrome web store, which should also tell you something about its usefulness and legitimacy.
If you find 3D Tree among your browser's extensions, it's best to remove it.