i know it sounds lame, but my hubby always seems to appreciate the card more than any gift. i get the ones that are blank, or nearly blank, inside and try to tell him how i feel. this year all it said was happy anniversary to my lover and best friend, this year, last year, and many more.

lame, i know, but he loved it anyway cause it's from the heart.
there was also a time i sent him flowers at work. his coworkers made fun, but i'd never sent him flowers before ... actually, no-one had ... and he was really touched. plus, if you look for it, you can find the feelings and thoughts that certain flowers represent. it's not exactly scientific, but through poetry and tradition, certain flowers have come to represent certain feelings. put together a bouquet that expresses all you want to, along with a little explanation of what the flowers you chose have come to mean.
with that and the card, he'll know it's from the heart. you want to tell him something, not just give him somehting. i think this would be a good way to do that.
or going along the lines of chey's bench idea ... if you want to give him someplace to go when he needs to get away a bit, how about a hammock? even a two person hammock incase he wants to share?

if you have a place to hang it that is .... or don't already have one.
i love your tree and bench idea chey! how sweet that would be to sit on in one’s dotage and reminisce.