9 Answers

Put a large plant on it...

If the top is level you could make it into a nice outdoor table.

Large Redwood tree stumps were selling to Japanese buyers 15 years ago for $6000.00 each. If you set up an automatic mister and start moss you may be able to get it looking great in a few years. Consult Bonsai  gardeners in your area and take your time to develop skill with the art form and processes.

Also I decorated a stump by turning it into an 8 foot high mushroom with caterpillar and hookah like Alice In Wonderland around 1980 to see how it would look as an art project.

A friend used rounds cut from trees about 25 inches long, padded the end and applied fabric with decorative print and lacy fringe. She called them "occasional stumps" as decoration outside her cabin in the woods.

Plenty of tinsel should do the trick

No I do not know how you decorate a tree stump so it looks nice

Grow a climber plant onto it,or some ivy and if the top is flat sit a bird bath dish on it.

 Here's another suggestion...

Put your head on it and pretend it's halloween.

Carve it into something that means something to you. My father in-law had 2, he used a chainsaw to carve them into crosses... They get tons on compliments on them.