Finished German tree...but different than Spanish
Interesting: I've learned German fewer words, but have earned more XP than when I completed the Spanish tree. It also seems to be much harder to keep the lessons coloured Gold - with Spanish I had a fully golden tree when I completed after about four months. German has been quicker (two months), but only half my tree is gold, even though I'm doing ten revisions a day!
Does the course have fewer words or did you just learn fewer? If they have about the same amount, I can explain you problem:
Doulingo claims to know, how good you know your words. So, if you don't remember the German words as well as you do the Spanish ones, the lessons won't be gold, because Duolingo assumes (rightly so), that you do not remember the words.
Also, having done both courses, I think that the vocabulary in Spanish is much easier to learn since most words have the same Latin source, which (quick side note) I think is a bit sad, since I don't actually need to repeat these words. Only the ones that are different are worthy of learning, the other ones you know after one or two repetitions. (My feeling tells me, that the frequently used words are similar in German and English (and - und, we - wir, gehen - go...), the rarely used words are more similar between English and Spanish (ciudadano - citizen, oportunidades - opportunities)). So, the different words are easier to learn in Spanish, because you use them all the time, while in German the frequently used words are easier to learn, but you miss the rest.
So, if you are a native English speaker, you will most likely have an easier time remembering the words from the Spanish lessons than the ones from the German lessons.
Edit: You did not ask a question, so I did not try to answer. It's just my opinion on what you wrote.
I think the course has fewer words. However, not all of the words in the German course appear on Words page. Not sure if that is the same for others. Thanks for your reply. I did Spanish in the old format where you had a limited number of hearts - maybe I've been a little lazier and so not so accurate without the deterrent of a lost heart,