Functions to initialize and expand a ring of tracheids to simulate secondary growth.
woodformation_initRing()
woodformation_temperatureEffect(
Tc,
Y_T = 5,
DHa = 87500,
DSd = 1090,
DHd = 333000
)
woodformation_relativeExpansionRate(psi, Tc, pi, phi, Y_P, Y_T)
woodformation_growRing(
ring,
psi,
Tc,
Nc = 8.85,
phi0 = 0.13,
pi0 = -0.8,
CRD0 = 8.3,
Y_P = 0.05,
Y_T = 5,
h = 0.043 * 1.8,
s = 1.8
)
woodformation_relativeGrowthRate(dbh1, dbh2, yeardiff, lower = -2, upper = 8)Temperature in Celsius.
Temperature yield threshold (in Celsius)
Enthalpy of activation, enthalpy difference and entropy difference between the catalytically active and inactive states of the enzymatic system (Parent et al. 2010).
Water potential (in MPa).
Osmotic potential (in MPa)
Cell extensibility (in MPa-1 day-1)
Turgor pressure yield threshold (in MPa)
An object of class ring returned by function woodformation_initRing.
Number of active cells in the cambium.
Initial value of cell extensibility (in MPa-1 day-1)
Initial value of cell osmotic potential (in MPa)
Initial value of cell radial diameter
Cell wall hardening coefficient (in day-1)
Cell wall softening coefficient (unitless)
Initial and final diameter at breast height.
Interval between dbh measurements, in years.
Lower and upper bounds for root finding.
Function woodformation_initRing() returns a list of class 'ring',
that is a list containing a data frame cells and two vectors: P and SA.
Dataframe cells contains the columns "formation_date", "phi", "pi" and "CRD" and as many rows as dates processed.
Vectors P and SA contain, respectively, the number of cells produced and the sapwood area
corresponding to the ring of cells (assuming a tangencial radius of 20 micrometers).
Function woodformation_growRing() modifies the input 'ring' object according to the environmental conditions given as input.
Function woodformation_relativeExpansionRate() returns a numeric scalar with the relative expansion rate.
Function woodformation_temperatureEffect() returns a scalar between 0 and 1 reflecting the temperature effect on tissue formation rate.
Function woodformation_relativeGrowthRate returns the annual growth rate, relative to cambium perimeter, estimated from initial and final diameter values.
Code modified from package xylomod by Antoine Cabon, available at GitHub
Cabon A, Fernández-de-Uña L, Gea-Izquierdo G, Meinzer FC, Woodruff DR, Martínez-Vilalta J, De Cáceres M. 2020a. Water potential control of turgor-driven tracheid enlargement in Scots pine at its xeric distribution edge. New Phytologist 225: 209–221.
Cabon A, Peters RL, Fonti P, Martínez-Vilalta J, De Cáceres M. 2020b. Temperature and water potential co-limit stem cambial activity along a steep elevational gradient. New Phytologist: nph.16456.
Parent, B., O. Turc, Y. Gibon, M. Stitt, and F. Tardieu. 2010. Modelling temperature-compensated physiological rates, based on the co-ordination of responses to temperature of developmental processes. Journal of Experimental Botany 61:2057–2069.