TY - JOUR

T1 - The oldest known clones of Salix herbacea growing in the Northern Apennines, Italy are at least 2000 years old

AU - Centenaro, Giada

AU - Petraglia, Alessandro

AU - Carbognani, Michele

AU - Piotti, Andrea

AU - Hudek, Csilla

AU - Büntgen, Ulf

AU - Crivellaro, Alan

PY - 2023/10/31

Y1 - 2023/10/31

N2 - Premise: Dominant in many ecosystems around the world, clonal plants can reach considerable ages and sizes. Due to their modular growth patterns, individual clonal plants (genets) can consist of many subunits (ramets). Since single ramets do not reflect the actual age of genets, the ratio between genet size (radius) and longitudinal annual growth rate (LAGR) of living ramets is often used to approximate the age of clonal plants. However, information on how the LAGR changes along ramets and how LAGR variability may affect age estimates of genets is still limited. Methods: We assessed the variability of LAGR based on wood‐section position along the ramets and on the duration of the growing season on three genetically distinct genets of Salix herbacea growing in the Northern Apennines (Italy). We compared genet ages estimated by dividing genet radius by the LAGRs of its ramets. Results: LAGR increased significantly from the stem apex to the root collar; indicating that ramet growth rate decreased with time. Furthermore, a difference of ca. 2 weeks in the onset of the growing period did not impact LAGR. Considering the high LAGR variability, we estimated that the three genets started to grow between ~2100 and ~7000 years ago, which makes them the oldest known clones of S. herbacea even considering the most conservative age estimate. Conclusions: Our findings indicate that analyzing ramets at the root collar provides an integrative measurement of their overall LAGR, which is crucial for estimating the age of genets.

AB - Premise: Dominant in many ecosystems around the world, clonal plants can reach considerable ages and sizes. Due to their modular growth patterns, individual clonal plants (genets) can consist of many subunits (ramets). Since single ramets do not reflect the actual age of genets, the ratio between genet size (radius) and longitudinal annual growth rate (LAGR) of living ramets is often used to approximate the age of clonal plants. However, information on how the LAGR changes along ramets and how LAGR variability may affect age estimates of genets is still limited. Methods: We assessed the variability of LAGR based on wood‐section position along the ramets and on the duration of the growing season on three genetically distinct genets of Salix herbacea growing in the Northern Apennines (Italy). We compared genet ages estimated by dividing genet radius by the LAGRs of its ramets. Results: LAGR increased significantly from the stem apex to the root collar; indicating that ramet growth rate decreased with time. Furthermore, a difference of ca. 2 weeks in the onset of the growing period did not impact LAGR. Considering the high LAGR variability, we estimated that the three genets started to grow between ~2100 and ~7000 years ago, which makes them the oldest known clones of S. herbacea even considering the most conservative age estimate. Conclusions: Our findings indicate that analyzing ramets at the root collar provides an integrative measurement of their overall LAGR, which is crucial for estimating the age of genets.

KW - dwarf shrub

KW - growth rings

KW - genet size

KW - snowbed willow

KW - bud scars

KW - stem longitudinal growth

KW - clonal growth

KW - relict population

KW - population persistence

U2 - 10.1002/ajb2.16243

DO - 10.1002/ajb2.16243

M3 - Journal article

VL - 110

SP - e16243

JO - American Journal of Botany

JF - American Journal of Botany

SN - 0002-9122

IS - 10

M1 - e16243

ER -