The tree image is the default reflection used in the viewport. I have never used C4D Lite, but assuming it acts in the same way as the full version if you’re going to use both the Reflectance channel and the Environment channel you need to set the Attenuation in the Reflectance channel to “Additive” in order to see the Environment channel. All the settings in C4D can easily be confusing, so I would recommend getting familiar with the Help files. You can right click on any parameter and select “Show Help” to access them. Here’s a screenshot from the Help files for the Environment parameters concerning what I referred to above: