You can convert your favorite tree to a MacPaint document, for later publication, as follows:
Get the whole tree on the screen, if possible. Hold down command and shift, and type 3. (Command is the key with the curly symbol that resembles a superhighway interchange.) This will save the entire screen, as you see it, in a file called Screen 0. Now you quit and use MacPaint to tidy up Screen 0 to your taste.
If the whole tree doesn't fit on the screen all at once, you will have to do this in stages. Get one part showing in the window and type Command-shift-3, which will save the screen to Screen 0. Scroll the window until the next part is visible and hit command- shift-3 again, which will save the screen in the file Screen 1.
When you have "photographed" each part of your tree, go to MacPaint. Call up each piece, Screen 0 through Screen whatever, one at a time, select the good part with the selection rectangle, and copy it to the scrapbook. When you have all the pieces in the scrapbook, you can paste them together into one big document.
If you are unfamiliar with the above process, you should reread the appropriate sections in the Macintosh and the MacPaint manuals.
With large trees, you may have a problem with running out of space on your disk. If this happens, try moving Screen 0, etc. to a disk other than your Paint disk. To use them with MacPaint, start up MacPaint, choose Open, then choose Eject and stick in the disk with Screen 0, etc.