DOI: 10.5061/dryad.1cn19
title: Data from: Environmental conditions and vascular cambium regulate carbon allocation to xylem growth in deciduous oaks

description: Environmental conditions and the structure of the dormant cambium are
 assumed to affect seasonal patterns of cambial activity, hence controlling
 allocation of non-structural carbohydrates (NSC) to growth. However,
 seasonal dynamics of xylogenesis, and their connections with NSC content
 and dormant cambium size, have been rarely assessed along an environmental
 gradient. We monitored xylogenesis and leaf phenology during 2012 and
 2013, and NSC in 2012, for the drought-sensitive Quercus robur and the
 drought-tolerant Quercus pyrenaica along a water-availability gradient in
 the north-western Iberian Peninsula, and analysed dependencies of xylem
 production and phenology on the number of cells in dormant cambium. Study
 oak species showed comparable seasonal fluctuations in cambial activity
 and NSC content, despite Q. pyrenaica had a shorter growing season and a
 lower wood production than Q. robur. A sharp drop in spring NSC levels at
 all study sites evidenced that stored carbohydrates were crucial for
 earlywood formation. Under drier conditions, both species extended the
 growing period in spring and autumn, but reduced and even stopped
 xylogenesis in summer, showing an enhanced NSC accumulation before
 dormancy. A higher number of cells in dormant cambium of large dominant
 oaks accounted for their wider xylem increments and longer active periods.
 Our study demonstrates that xylogenesis is modulated by predisposing
 effects of dormant cambium size on xylem production and growing season
 length. Moreover, the high plasticity of cambial activity in deciduous
 oaks would confer resistance against recurrent summer drought through the
 improvement of the NSC status.
description: Phenological obserations
 and wood anatomy measurementsPhenolological and
 anatomical data collected in the field during 2012 and 2013 in NW Iberian
 Peninsula (Wet, Intermediate and Dry sites). This file contains 5
 spreadsheets including for each sampling date: (i) Leaf and cambial
 phenology binary data; (ii) mean number of cambial cells; (iii) width of
 the enlarging and maturing xylem zones, and (iv) soluble sugar and starch
 concentrations (expressed as percentage of dry matter). In addition, (v)
 individual tree characteristics are summarized in the last spreadsheet.
 (i) Spp is species, doy is day of year, EW onset is onset of earlywood
 enlargement, LW onset is onset of latewood enlargement, Max cambial cell
 is maximum number of cambial cells, Max enlargement is maximum width of
 enlarging xylem, Cessation1 is latewood growth cessation without
 considering autumn regrowth, Cessation2 is latewood growth cessation
 considering autumn regrowth, Regrowth is regrowth period in autumn; (ii)
 No cambial cells is the mean number of cambial cells; (iii) EnlargingRAW
 is width of enlarging xylem, MaturingRAW is width of both maturing and
 mature xylem; (v) EWD onset is the doy for earlywood growth onset, LWD
 cessation is the doy for latewood growth cessation, Dormant cambial cells
 is the radial number of dormant cambial cells. Study species are Quercus
 robur (Qrob) and Quercus pyrenaica (Qpyr).FE-2016-00376.R2_Perez de Lis
 et al.xlsx