Scars from human-tree interactions: pollarding, pathogens, body reserves, and long-term response by Salix fragilis L. (Salicaceae) in Scodovacca, Italy

ABSTRACT

Arboriculture provides opportunities for assessing long-term tree-environment interactions. We assessed the surrounding context, scars, re-sprouts, and absolute width-growth of twenty-four Salix fragilis trees pollarded by the grandfather, father, and son of one family covering 120 years, quantifying the effects of cut, microorganism-infection, and body-accumulated photosynthate on the pollards’ resprout-and-growth. We determined pollard diameter, age, scars-number (C) and basal area (C_AB), median times pruned (Cmn), putrid holes number (H), cumulative length (HL), and length-average (H_AV), and two indicators of remaining photosynthate (Q, and Q_AV). Response variables were number of re-sprouts (R_N), re-sprout-basal area (R_AB), and trunk’s Absolute Growth (AG; Classic (MLR), and Bayesian Multiple Linear Regressions (BMLR)). The pollards experienced similar incoming light, water, CO₂, nutrients, and temperatures. Higher C-values for 40-year-old pollards produced higher H-values (Linear Regression, R² = 0.54, p = 0.02; Bayesian Linear Regression: BF10 = 3.79, n = 8) suggesting more infection when cutting. R_N slightly changed in response to life-long accumulated C_AB, Cmn, H, and H_AV (BMLR, BF10 from 1.10 to 2.82, n = 24). R_AB slightly changed responding to C, H, H_AV, Q, and Q_AV (BMLR, BF10 = 1.11; MLR: p < 0.05, n = 24). AG declined in response to Cmn (MLR, R2 = 0.38, p < 0.001, n = 24). Thus, under favourable conditions severely wounded-and-infected trees keep re-sprouting and growing, even if growth is reduced.

KEYWORDS:

• Bayesian statistics
• growth and re-sprouting
• microbial infection
• pruning, tree biographies

Acknowledgment

To the anonymous land-owner allowing us to study the trees planted and cared for by himself, his father, and grandfather.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03071375.2024.2358675

Additional information

Notes on contributors

Edgardo I. Garrido-Pérez

Edgardo I. Garrido-Pérez. Staff researcher at the Coiba Scientific Station – Coiba AIP (Panama). He studied for a PhD at the Centro de Investigación Científica de Yucatán (Mexico) and the Goettingen University (Germany). He is a forest (ethno)ecologist studying the effects of human intervention on plant communities, populations, and individuals applying the Historical Ecology approach in both Europe and the Neotropics.

Edgardo Díaz-Ferguson

Edgardo Díaz-Ferguson. Head of the Coiba Scientific Station – Coiba AIP (Panama). He gained his PhD at the University of Cádiz (Spain) and has undertaken Post-Docs at Washington, Florida, Georgia, and Auburn Universities (USA). He is a marine ecologist and geneticist with more than 22 years of experience studying both basic and human-determined changes of marine wildlife.