Darken the mood
1 Add a vignette
In the Develop module, click the Effects panel, then click the PostCrop Vignette tool. Leave the Style set to Highlight Priority. Drag Amount to -35. This darkens the corners and some of the edges. Increase Midpoint to 59 to push the effect nearer the frame edge.
2 Refine the vignette
By default, a Roundness of 0 creates an oval shape that suits the photo’s landscape shape. Drag Roundness left to get a rectangular shape. Drag it right to +35 to create a more oval-shaped vignette that darkens the vertical edges a bit more. Leave Feather on 50.
3 Crop the photo
Click the Crop Overlay icon in the toolbar below the histogram. The crop overlay will appear over the entire photo. Click Original and choose a new aspect ratio of 1x1. This changes the crop to a square shape. Drag inside the crop overlay to include all of the branches.
4 Re-evaluate the vignette
Click Done to apply the crop and create a square version of the landscape. This loses the bland edges of the frame and makes the tree more prominent. The vignette effect we created earlier will reappear in the new corners of the cropped photo.