In a world dominated by climate crisis, trees matter. Gregory Bryda’s The Trees of the Cross: Wood as Subject and Medium in the Art of Late Medieval Germany lends historical perspective to our understanding of trees and what they mean to humanity. With a focus on wood as artistic material and medium in late medieval Germany, Bryda explains the polyvalency of arboreal imagery, sharing with us its secret cross-referencing language. Reflecting on the recursive relationship between nature and the Church prior to the Reformation, the author investigates how it was mediated by the wood of the cross, both depicted and in substance. At this time trees materially referenced the cross, which was both instrument of Christ’s death and human salvation. Wood and greenery were used in acts of sanctification performed in church liturgy, at its turn entwined with the cyclic occurrence of the seasons. The feasts of the cross were celebrated in the spring months of growth and renewal, and the thaumaturgical effect of holy images in wood mediums was potentiated by processing them out of the sanctuary into the surrounding countryside. In exchange, the natural world was brought into German churches as living wood in the form of garlands and greenery and set upon the altar to reanimate depictions of saints and their stories. Taking its cue from seasonal progression, Bryda’s text pivots around the spring and autumn festivals of the cross.

From an interdisciplinary stance, the author casts a wide net in his analysis of visual material and ideas. Contemplating the ordinary alongside the extraordinary, he aims at a comprehensive understanding of what trees meant in the pre-modern age. Unlike earlier publications concentrating on verdant architectural forms or limewood sculpture, Bryda’s analysis pays close attention to folkloristic practices and introduces new ethnographic material, “buttressed by complementary evidence in the history of science, medicine, and literature” (13). Organized into four chapters, the book culminates with discussion of the Reformation’s effect on arboreal lines of thought. The text runs seamlessly with the flow of images in a publication of large format that is beautifully presented. Most of the art, illustrated in color, comes from the fifteenth and sixteenth centuries. The book publishes an impressive array of visual material, successfully demonstrating the singular appreciation German artists had for trees and their substance. It includes ample footnotes and a useful index but unfortunately lacks a bibliography.

Dedicated to the “vegetable saint”, the first chapter explores the Holy Cross as the only nonhuman Catholic saint. Opening with a full-page detail of the painted crucifix from the Tree of Life (ca.1310) by Pacino di Buonaguida, the Italian iconography provides terms of comparison for the crucifixus dolorosus in Santa Maria im Kapitol in Cologne (before 1304) illustrated across the binding. Once bright green, the German crucifix links typologically with the Tree of Life in Paradise. Transitional in nature, the Tree of the Cross was present in both celestial and terrestrial worlds. Eden’s tree lived on in its wood, spanning past and present times as an instrument of torture that offered human salvation. Acting with agency, it was able to determine its own destiny in apocryphal accounts. Legends of the cross were particularly well received in Germany, where feasts dedicated to the cross’s invention (May 3) and elevation (September 14) were celebrated outdoors. In this context, surrounded by nature, the cross functioned as a medial conduit for conjuring earthly fecundity. Arboreal imagery evoked not only the presence of Christ but also that of his mother, from whose stock or virga he descended. Bryda highlights the renewed popularity of the Tree of Jesse illustrating Christ’s lineage in late Medieval Germany, concluding with a thought-provoking discussion of the cross legend and the genealogical, arboreal, and aquatic themes that intersect with it in the Tree of Jesse altarpieces in the “fountain churches” of the Odenwald.

The second chapter focuses on the church’s appropriation of profane springtime rituals, with attention to the maypole. Because no medieval maypoles survived, discussion centers on descriptions of these trees in visual and textual records. Initially, the festive trees were contentious objects, with the church wary of encouraging the heathen-like activities of decorating, singing, dancing, and games that took place around them. An early reference to the maypole is found in Caesarius von Heisterbach’s (ca.1180–1240) denouncement of bad behavior at festivities in Aachen. Mayday merrymaking mapped onto the feasts of the True Cross in spring, an overlap in temporality that led to the maypole’s identification with the cross. In Henry Suso’s (1295–1366) imagery, the votive tree serves as a monument of sacrifice and rebirth that mediates humanity and nature. The Dominican friar prescribes it as a tool for meditational practice, a means of mystical ascent from the material to the immaterial world. Appreciation for the motif seems to have run high in mendicant circles. A later Franciscan compilation of daily prayers by Stephan Fridolin (1430–98) uses Mayday preparations as metaphors for the devotional activities carried out by Clarisse nuns in Nuremburg. Following meditational guidance from Franciscan saints Bonaventure and Clare, Fridolin urges the nuns to hang mirrors on their trees so they might see themselves alongside Christ in the mind’s eye. Both the maypole and the arma Christi (Passion instruments) decorating it, reference Christ, and Bryda points to this same unusual combination of folkloric and Christian symbols in the striking examples of German Whipping Posts. Sculpted in the round, these tall freestanding columns represent the support Christ was tied to at the flagellation.

Chapter three examines the semantic ability of wood to oscillate between subject and medium, paying particular attention to Matthias Grünewald’s (1470–1528) use of arboreal imagery. As Christ’s body became tangled with the tree on which he was crucified, artists began to stress botanical aspects in their portrayal of him. Reciprocally, the wood of the cross roughly shorn of its branches and oozing reddish sap, was also shown to suffer. Presenting two of Grünewald’s major altarpieces, Bryda explains how the healing properties of plants entwine with the salvific powers of Christ and the saints represented. On the high altar of the Antonite hospital church in Isenheim, Grünewald’s multimedia retable demonstrates a sensitivity to the symbolic and material relevance of trees and plants, whose essences were prescribed to patients in the adjacent infirmary. The artist’s meticulous description of medicinal plants suggests its panels were a visual repository for the order of Saint Anthony’s knowledge of healing (Emily Poore, Parergon, 2024). Painting Christ’s skin maculated and greening like bark, Grünewald presents him as both man and tree, offering a potent salvific image to alleviate both spiritual and physical aspects of human suffering. Resins and turpentines, supplied to artists and healers alike, were integral to mixing medicines and creating colors, and ultimately both were employed to ease human suffering. The earlier Heller altarpiece (1509–10), for which Grünewald painted four saints in grisaille, was a commission shared with Albrecht Dürer. Bryda points to programmatic continuity in the masters’ works, where Grünewald’s monochromatic medium on the altarpiece’s external shutters, visible during the winter months, plays counterpoint to the riotous color of Dürer’s Assumption panel, displayed during summertime Marian feasts.

Bryda dedicates his final chapter to the Eucharistic metaphor of Christ as vine and explores the symbolism of wood in the winemaking process. Opening with the unpainted wood sculpture of the Holy Blood Altarpiece (1499–1505) in the church of Saint James, Rothenburg ob der Tauber, the author explains how effectively the grape vines around the central scene of the Last Supper bind the iconography of the altarpiece to its Holy Blood relic and the Eucharistic wine on the altar. Just as the meaning of wood was weighted by potential identification with the cross and Christ on it, the significance of wine swelled with the possibility of becoming the blood of Christ. Miraculous at the altar, wine was consumed by secular and religious communities alike in its ordinary form. Wood played a key role in converting the material yield of vines into a liturgical mirror of Christ’s blood, and the mechanical wine press inspired a series of Eucharistic images. Within the sacred language of wine technology, the Preßbaum or Tree Press featured as a carpentered stand-in for the wood of the cross. Manual labor also presented medieval monks in monastic wineries with opportunities for religious contemplation, where every step of the winemaking process could be linked metaphorically with an episode of the Passion. “Christ was bound to a pillar as a vine to a pole,” Bonaventure writes in the Mystical Vine (Akenside Press, 2016, 27). Turning our attention to botanical exegesis in works like the “Berlin Vineyard Sermon”, written in fifteenth-century Swabia and Fridolin’s prayers for the Nuremburg nuns, Bryda illustrates the impact of this imagery in German lands.

The Protestant altar was no place for magical transformations of water, wine, plants, or greenery, according to Bryda. Indeed, many surviving records of plant-centered liturgical and popular rituals are written protests denouncing the moral decay of the Church. Where Catholic spiritualized cultivation centered around the imagery of Christ’s Passion, Protestants stuck to the letter of scripture, choosing to promote literal representation over metaphorical imagery. In this book Bryda accompanies his readers deep into the metaphorical forest of meaning, moving beyond superficial appearances to perceive the full pre-modern measure of trees’ entangled message of human potential, history, and hope.