This type of printing is not supported here.
The following work around may solve your problem:
1. On the print dialog adjust the paper size, orientation, width and height to approximate your final print size.
2. Click on [Download PDF].
3. Convert each page of the PDF into separate JPG files.
4. Using a drawing editor like ones found in Microsoft Office, Libre Office or a similar application, create a drawing with the dimensions of your finished print.
5. Import each JPG file of your tree into the drawing. Crop and fit them together as required.
6. Print this file on your large printer.
Sound like fun? Let us know how it works out.