English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Sap exudation is the process whereby trees such as sugar (Acer saccharum) andred maple (Acer rubrum) generate unusually high positive stem pressure inresponse to repeated cycles of freeze and thaw. This elevated xylem pressurepermits the sap to be harvested over a period of several weeks and hence is amajor factor in the viability of the maple syrup industry. The extensiveliterature on sap exudation documents competing hypotheses regarding thephysical and biological mechanisms that drive positive pressure generation inmaple, but to date relatively little effort has been expended on devisingmathematical models for the exudation process. In this paper, we utilize anexisting model of Graf et al. [J. Roy. Soc. Interface 12:20150665, 2015] thatdescribes heat and mass transport within the multiphase gas-liquid-ice mixturein the porous xylem tissue. The model captures the inherent multiscale natureof xylem transport by including phase change and osmotic transport in woodcells on the microscale, which is coupled to heat transport through the treestem on the macroscale. A parametric study based on simulations with synthetictemperature data identifies the model parameters that have greatest impact onstem pressure build-up. Measured daily temperature fluctuations are then usedas model inputs and the resulting simulated pressures are compared directlywith experimental measurements taken from mature red and sugar maple stemsduring the sap harvest season. The results demonstrate that our multiscalefreeze-thaw model reproduces realistic exudation behavior, thereby providingnovel insights into the specific physical mechanisms that dominate positivepressure generation in maple trees.

Experimental and computational comparison of freeze-thaw induced pressure generation in red and sugar maple