From: Sofia Bulgaria Registered: 2012-01-01 Posts: 90
Going for them as a group, I guess, would make them even harder (since you'd be learning similar words one after another). Personally, I still mistake about half of them, but considering that in my native language, I can't recognize most trees in the wild even if I tried, I don't think it's much of a miss to just remember they're trees, paying little attention to particulars unless you are familiar with that specific tree sort (and if you are, stories should come that much easier).
From: Massachusetts USA Registered: 2011-08-01 Posts: 530
I looked up all the trees that didn't sound familiar as I encountered them... once I saw the lists of common names on the wikipedia pages, there weren't any that I was totally unfamiliar with. Plus there's all that information about the tree if it's not very familiar once you see the other names the tree goes by.
It's fairly useless to memorize a lot of the tree kanji. Tree names are often written in katakana anyway, and even when they appear in kanji they get furigana fairly often. As chamcham said, a lot of them are more important for their appearance in names than for their actual tree meaning.
I know a lot of tree names in Hebrew (my native language) that I have no idea how they look like. I also know a lot of tree names in English that I have no idea about their exact meaning or how they look like. I'd be surprised if it actually matters at all.