Womb, cycles
In addition to the cyclical nature of deciduous trees mentioned already, a visual impact I got today from this card is not one of a "tree" at all, but it instead looks to me like a full uterus—either ready to menstruate or pregnant, gestating. So it's a very literal interpretation of the womanly, motherly nature of the Empress. This shedding even parallels the tree shedding its leaves toward its roots in autumn to make room for new growth in spring. Even the crescent moon reminds me of a new egg that is about to be released to start the cycle all over again. The moon is to the left, also traditionally representing receptivity or the feminine side.
So not only is the Empress tree round, soft, and cyclical—symbolically representing her femininity, she is also very graphically and literally a womb/uterus, in contrast to the very phallic Emperor.
I know we should discuss the Emperor on his own thread, but to me the two cards really have to be understood together, especially in this deck. His sun is on the right, although interestingly, it appears to be another eclipse (at least one other in the deck, despite how rare eclipses are: 2 Swords, and arguably Son of Pentacles in a partial eclipse). The eclipsed sun seems to balance the sliver of the moon—both beacons of celestial light, yet not fully illuminated. Although it's not exactly the same as an eclipse, the moon is empty when the sun is behind her in the same way that the sun is eclipsed when the moon is in front of him. But I don't see this as a blockage, exactly, but more the thread that ties the two together—they're complimentary by being opposite, but opposite at the same stage of their lives, the sun and moon aligned together looking toward the earth; Mother and Father directing a singular attention on their child, as opposed to a full moon and bright sun looking at both sides of the Earth.
A rather sexual way of looking at the two is to place the Empress above the Emperor, her white foundation enveloping his white background before union. And yet, his black foundation emerges from her black background. Their strength draws from each other, each taking turns in the foreground… the two cards exist together for me, even when only one is present in the spread. In either card, the other is present, even if not the active force. The fully expressed feminine force requires masculine context and vice versa—they coexist, either within a single person, a situation, or in relationship. The purer a polarity, the stronger its opposite must also be. They are equal expressions of duality that hint at the possibility of non-duality. We could even create an endless cycle of Empress above Emperor above Empress above Emperor in the endless cycle of polarity that reminds me of the classic Yin/Yang symbol—a representation of unity expressed through duality (which is also encompassed by the Justice card…)
Turning into a rambling tarot nerd here, so I'll leave it there before I get too far away from the Empress herself