Okay, the first image is the first try at revision. I decided to extend the sky all the way across the top of the painting. Also made the cove bigger and lost the slant. Started to add some additional color to the background foliage and tweak the sky holes a bit. Still did not like the fact that my focal tree is just kinda hanging out and not the star. Also, in this version, the background trees are not fading back like they need to and am still not happy with the lack of variation in the grass around the tree. Also noticed at this stage that the background hillside is pretty much one line and needs variation and also to be blued-down for it to recede into the background and show distance.
In the second photo of the painting, you will see that I addressed all those issues above. I toned down the size of the sky holes, varied the line in the background trees on the hillside and also brought the line down so the sky holes made more sense in relationship to the sky. The other thing that I did was to vary the colors in the grass and tone down the background colors a little so the tree now takes center stage. I also softened the bushes in the intermediate part of the scene so they would not compete with my tree. By changing the grasses, and toning down and mellowing the background my tree now becomes the star. And I didn't have to change a thing about the tree itself-it just needed the supporting players to get out of its light.
I also softened around the water's edge in the cove to give a little more variation where the shoreline meets the land and to soften the slope down to the water.
Hope this helps you to feel more confident when you need to re-visit a painting-It's fun exploring them with new eyes and finding ways to improve upon your original idea. Especially when you do a plein aire with a limited time crunch. They make a great learning too.