Abstract
Background: The mechanism by which water transport, tree growth and heartwood formation are balanced is poorly understood. Aims: To test the hypothesis that xylem formation drives heartwood production through changes in water transport to regulate sapwood area. Methods: We measured changes in sap flux at multiple depths across the sapwood to heartwood boundary in Sitka spruce (Picea sitchensis) from May 2009–October 2010 using the Heat Field Deformation method. Results: The radial sap flux profile was peaked with maximum flux occurring 1–2 cm below bark before reducing to the heartwood boundary (tail). Changes occurred in two stages. The depth of peak sap flux (D) extended outwards as new xylem formed during the growing season, giving an annual increment (AI). Water transport reduced in the tail sometime during dormancy, from November to March. The correlation between AI and D was good however, these variables and the increase in sapwood area correlated poorly with the extent of heartwood formed. Conclusions: Heartwood formed during the dormant period in Sitka spruce in Great Britain. Xylem formation did not directly drive heartwood production; however, changes in specific conductivity need consideration. Reduced transport in the inner sapwood could provide a temporal signal for heartwood formation in pre-conditioned cells.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
