Jana Hacurová, Hanuš Vavrčík, David Dušek, Jakub Hacura, Mary Vetter, Vladimír Gryc, Dave Sauchyn
Xylogenesis of Pseudotsuga menziesii in Canadian Rockies under the influence of age and the elevation gradient
Dendrobiology 2025, vol. 93: 108-120
https://doi.org/10.12657/denbio.093.008
Abstract:
We studied cambial activity (CA; onset, duration, cessation), cambium cells (CC; numbers during dormancy and throughout the growing season), and the process of xylogenesis (phases of xylogenesis: postcambial growth [PC], cell wall thickening and lignification [SW], mature cells [MT], and cambial productivity [CP]) in montane forest stands of Douglas fir (Pseudotsuga menziesii (Mirbel) Franco var. glauca (Mayr) Franco) in southern Alberta, Canada. We assessed the relationship between these dependent variables and exogenous factors (elevation and meteorological data) as well as endogenous regulation (tree age). Microcores were collected weekly throughout the growing season (April–October 2013) from 36 trees in two age categories located at three sites at different elevations (1480, 1670, and 1820 m a.s.l.). Samples were embedded, dehydrated, sectioned, and stained before counting cells and analysing xylogenesis in three randomly selected radial rows per sample. Gompertz growth function curves were generated for each site and age group, and linear regression was used to evaluate the relationship between cell production rate and meteorological variables. Location significantly impacted CA. Although tree age did not influence the onset of CA, it was associated with cambium cell numbers during the growing season. The duration of CA and the final xylem increment were related to location, while tree age showed a weaker relationship. The duration of CA, as calculated with the Gompertz function, increased with decreasing elevation and was prolonged in older trees. Overall, location strongly affects cambial activity and xylogenesis, while the impact of tree age was insignificant.
Keywords: cambial activity, wood formation, Gompertz growth function, douglas-fir, montane forest