Joan Mitchell's Trees series, spanning from the late 1960s until the artist's later years, embodies a profound exploration of nature and abstraction, capturing the essence of trees through her signature expressionistic style. The series, showcased in exhibitions such as one at Cheim & Read in cooperation with the Joan Mitchell Foundation, includes large-scale canvases that reflect Mitchell's visceral relationship with the natural landscape. These works, dating from 1964 to 1991, reveal her fascination with the structure and form of trees, moving from the interlacing branches of earlier works to the thick, almost sculptural representations of groves in her later pieces​ (Joan Mitchell Foundation)​.

Mitchell, a pivotal figure in the Abstract Expressionist movement, distinguished herself not only by her vibrant and dynamic brushwork but also by her unique approach to capturing her subjects. Unlike her contemporaries, who often delved into abstraction as a means of expressing the psyche, Mitchell grounded her abstract language in the physical and emotional experience of nature. This connection is particularly evident in her Trees series, where she employs a combination of rhythmic, swirling lines and a riotous use of color to evoke the essence of trees, rather than their literal forms. This approach allowed her to express what she described as the "physical, bodily nature of our experience of the world around us," achieving a balance between abstraction and a deeply felt representation of nature​ (Artsy)​.

Mitchell's relationship with trees, and nature more broadly, was integral to her work and well-being. She spoke of a time when, ill and hospitalized, the sight of fir trees from her window filled her with a profound sense of happiness and vitality, inspiring her to paint once again. This anecdote underscores the depth of her connection to the natural world and how it fueled her creative process. Her works are not mere depictions but are imbued with the life force of their subjects, embodying both the tumultuous and serene aspects of nature​ (Artsy)​.

Through her Trees series, Joan Mitchell invites viewers into a space where nature and emotion intersect, where the gestural and the structural coalesce to form a deeply personal yet universally resonant visual language. Her ability to capture the essence of trees in her paintings reflects a broader endeavor to convey the complexity of human experience through the lens of the natural world, making her one of the most distinctive voices in post-war American art.