There is a big tree in front of the shop. Is it good or bad from the perspective of geomantic omen?

This is inconclusive. Some trees are good trees, such as the big mulberry tree in front of Liu Bei's yard, which is a sign of good luck. Zhang Fei said that there will be dignitaries.

Some trees are not good, such as the story of Cao Cao's "cutting down trees and spraying blood", and then Cao Cao died not long after.

The answer upstairs is correct, but it is also wrong. Elms are really good in some cases, but there are also bad times. Whether it is good or not depends on the orientation, latitude and longitude of the house and the current position. The size, height and branches of the tree are also factors that affect Feng Shui. You can't just look at a tree in front of your house and decide whether it is good or bad!

I believe my answer will make you a little satisfied. In addition, my master is Huang Dao, an internationally renowned feng shui master, who has shown feng shui to Olympic venues such as the Bird's Nest. You can search him if you are interested, and you should be able to find his website. There is a lot of knowledge about Feng Shui in his website. You can check it, so I won't post the website, lest the administrator say I'm advertising!

I hope the answer will help you!