cambium: Finds radial bole necrosis depth

View source: R/Flora.R

cambiumR Documentation

Finds radial bole necrosis depth

Description

Depth to which the cambium of a tree recieves lethal heating

Usage

cambium(
  Surf,
  Plant,
  percentile = 0.95,
  Height = 0.1,
  woodDensity = 700,
  barkDensity = 500,
  bark = 0.04,
  comBark = 700,
  resBark = 45,
  phloem = 0.01,
  RH = 0.2,
  moisture = 1,
  bMoisture = 0.2,
  distance = 50,
  trail = 100,
  var = 10,
  diameter = 20,
  Pressure = 1013.25,
  Altitude = 0,
  startTemp = 25,
  necT = 60,
  surfDecl = 10,
  updateProgress = NULL
)

Arguments

Surf

The dataframe produced by the function 'summary',

Plant

The dataframe produced by the function 'repFlame'.

percentile

defines which heating statistics are used for each second, from 0 (min) to 1 (max)

Height

The height on the bole directly over ground (m)

woodDensity

The density of wood in the tree or log housing the hollow (kg/m3)

barkDensity

The density of bark in the tree or log housing the hollow (kg/m3)

bark

The thickness of bark on the thinnest side of the hollow (m)

comBark

Temperature directly under the burning bark (C)

resBark

Flame residence in the tree bark (s)

phloem

Thickness of the tree phloem (depth to cambium, m)

RH

The relative humidity (0-1)

moisture

The proportion oven-dry weight of moisture in the wood

bMoisture

The proportion oven-dry weight of moisture in the bark

distance

The furthest horizontal distance between the flame origin and the point (m)

trail

The number of seconds to continue modelling after all flames have extinguished

var

The angle in degrees that the plume spreads above/below a central vector

diameter

depth of the litter layer (mm)

Pressure

Sea level atmospheric pressure (hPa)

Altitude

Height above sea level (m)

startTemp

The starting temperature of wood and bark (deg C)

necT

Temperature of necrosis (deg C)

surfDecl

adjusts the rate at which surface flame length declines after the front

updateProgress

Progress bar for use in the dashboard

Details

Utilises the output tables from 'threat' and 'radiation', and adds to these the Reynolds Number, heat transfer coefficients, Newton's convective energy transfer coefficient, and the temperature of the object each second.

Reynolds Number utilises a standard formulation (e.g. Gordon, N. T., McMahon, T. A. & Finlayson, B. L. Stream hydrology: an introduction for ecologists. (Wiley, 1992))

Convective heat transfer coefficients use the widely adopted formulations of Williams, F. A. Urban and wildland fire phenomenology. Prog. Energy Combust. Sci. 8, 317–354 (1982), and Drysdale, D. An introduction to fire dynamics. (John Wiley and Sons, 1985) utilising a Prandtl number of 0.7.

Heat is transferred into the bark and timber using Fourier's Law

Thermal conductivity of bark is modelled as per Martin, R. E. Thermal properties of bark. For. Prod. J. 13, 419–426 (1963)

Specific heat of bark is modelled using Kain, G., Barbu, M. C., Hinterreiter, S., Richter, K. & Petutschnigg, A. Using bark as a heat insulation material. BioResources 8, 3718–3731 (2013)

Thermal conductivity of wood is modelled using an approach from Kollmann, F. F. P. & Cote, W. A. Principles of wood science and technology I. Solid wood. (Springer-Verlag, 1968)

Evaporates water at 100 degrees C

Specific heat of wood is derived from an established empirical relationship in Volbehr, B. Swelling of wood fiber. PhD Thesis. (University of Kiel, 1896)

Continues heating of the bole in the wake of the front for the duration of the surface fire for a period determined using Burrows, N. D. Flame residence times and rates of weight loss of eucalypt forest fuel particles. Int. J. Wildl. Fire 10, 137–143 (2001). Flame lengths are decreased exponentially over this period

Bark is assumed to ignite, and burn for an average of resBark seconds, with the default value of 45s used as a mean for figure 6c in Penman, T. D., Cawson, J. G., Murphy, S. & Duff, T. J. Messmate Stringybark: bark ignitability and burning sustainability in relation to fragment dimensions, hazard and time since fire. Int. J. Wildl. Fire 26, 866–876 (2017).

Heats an area of 0.01m2

Value

dataframe


pzylstra/frame_r documentation built on Nov. 12, 2023, 1:55 a.m.