Using foregrounds in photos is a technique photographers use to help lead the eyes of the viewers to the subject. Positioned in front of the subject, not to obscure, but to give depth and add interest, there's a lot of different foregrounds you can use to enhance the look of your photos. Among those would be trees, posts, and even people, to make sure that your photo doesn't look boring.
Below is an example of a photo with a foreground. With Megan making eye contact with the camera, add to that the couple's sweet body language, and Manuel looking away and seemingly pensive, yes, this would have been just an okay shot. BUT what made this photo more interesting and different is the leaves blurred softly in the foreground. It instantly added depth to the photograph. There's life. Let me add, an element used as a foreground should not draw attention to itself, but It should draw the viewer's eye to the subject. Not only are foregrounds an effective means of directing the viewer's attention, it also adds interest and depth to the photo.
And wow, I just shared another valuable photography tip now. Look at that. :)