Thanks to the labors of generations of scientists, an extraordinary trove of information is available about events occurring over the giant span of geologic time. In approaching this immense body of knowledge, aesthetic experience can be a guide. The leaves of trees, for one, offer regular aesthetic encounters, provoking questions that can be entryways into the epic story of evolution.
For a wonderful example of the intrigue of leaves, take look at the Yulan Magnolia leaf (M. denudata) and the Tulip tree leaf (L. chinense) below, gathered during a bright fall day from sidewalks in Shanghai. Their similar textures and venation indicate common ancestry (they are both in the family Magnoliaceae) but how did the Tulip tree leaf get its distinctive shape? The American botanist Theodor Holm dwelled at length on this question in an 1895 monograph and concluded only that the Magnolia leaf was the likely predecessor. Is the curious angle at the apex of the Tulip tree leaf a trait that gave it an advantage in more humid climates, with more edge length for transpiration? If so, what were conditions like at the boundary of the Magnolia’s territory where edge length suddenly mattered? And why did the leaf split there and not in the usual places like the leaves of the maple or the plane tree?
These questions are not merely academic. To study a leaf is to regain a vivid interest in the human present, that is unfolding in correspondence with the rest of nature and in relation to our common past.
The Book of Leaves is an artwork-in-progress that further probes the narrative pathways opened through our aesthetic experience of leaves. It consists of a Chinese scroll on which leaves from common trees are arranged in order of each species’ appearance in the fossil record, paired with a gradually evolving field guide to commonly sighted trees around Shanghai. The first exhibition of the Book of Leaves took place last weekend at Shanghai’s Gongyi Xintiandi, a campus for civil society organizations run by the public-private partnership NPI, as part of their annual partner fair.
In preparation for the event, eight high school students from Xiwai International School affiliated with Roots & Shoots conducted a survey of trees at their school, gathering leaves fallen to the ground and separating them by species. Each student chose a leaf to research. Information was added to the growing field guide to common trees in Shanghai (click here to view). The following weekend at Gongyi Xintiandi the students led the public through a tree survey in the morning along with project volunteers. Leaves were combined with specimens from the prior weekend, separated by species and assembled on an 8-meter long scroll according to the geologic age in which the plant genus appeared (as indicated in the field guide).
Calligraphers Dong Xiaoxun (董晓迅）and Zhou Liying (周丽英）added text to the scroll, including names of each species and a poem composed extemporaneously by Frederick Zhang (张敏)，a member of the Roots and Shoots team:
回望千古历苍穹，
行遍群山立秀木。
苏芳落栗皆枯荣，
兰若缥碧孕于土。
By the end of the first day the scroll was nearing completion, with approximately 30 species represented. The following day the public was invited to choose their favorite leaf, draw it on the scroll using pencils, brush and watercolor, and take their chosen leaf back home in a card for pressing and further examination.
The residuals of this project to date include a scroll covered in individual renderings of leaves, that itself is the residual of a collection of leaf specimens, each of which is a residual of a tree, etc. They also include the photographic and textual documentation that can continue to be built on. More important are the questions left in the minds of all participants and the glimmerings of questions as yet unformed.
To view the Book of Leaves, the field guide and other leavings please visit the archive.