Description of EnvCalc Output Variables
The following brief descriptions of variables are intended for quick reference, not
necessarily to tell you everything you need to know to understand how a variable
is calculated. The logic of the calculation of environmental variables is detailed in
Chapter 4 of Binford (2001) Constructing Frames of Reference. The strategy of
projecting hunter-gatherer variables is discussed in Chapter 5 (e.g.: 35-52; 154,
156, 199-200), though not all of the projected variables are mentioned
specifically. The section on the Terrestrial Model is in Chapter 6 (pp174-188).
Some of the variables included in your data file and in this list are new since the
Binford (2001) publication. Some have not been discussed specifically in print.
The density controlled hunter-gatherer subsistence projections are a good
example. I developed these for research I was doing. Since I find them useful, I
thought others might, too. There are a couple of forthcoming publications which
uses them, but no specific discussion of their calculation.
The growth rate variables at the end of the list/ file are referred to by Binford
(1999) in his paper “Time as a Clue to Cause?” which is published in the
Proceedings of the British Academy. Bob Hard and I also use the REPRATE
variable in our models for where to expect the earliest intensification in a region.
Input Variables
STATE
Abbreviation for State or Nation of weather station
STATENO Identification of NOAA/NCDC weather station number by state
STATION
Name of weather station
LAT
N or S
LATITUDE Decimal degrees of latitude (40 deg 30 min = 40.5)
LONG
E or W
LONGITUD Decimal degrees of longitude (100 deg 45 min = 100.75)
ELEV
Elevation in feet
COKLM
Distance to the nearest coast in kilometers
SOIL
Primary soil order (see data info for list)
SOIL2
Secondary soil order (if necessary)
TJAN…TDEC
Mean Monthly Temperature (C)
RJAN…RDEC
Mean Monthly Precipitation (mm)
Simple Summaries of Input Variables
MWM
Mean temperature in the warmest month (C)
MCM
Mean temperature in the coolest month (C)
RHIGH
Mean rainfall in the wettest month (mm)
RLOW
Mean rainfall in the driest month (mm)
RRCORR
Correlation between month with highest temperature and month
with highest rainfall (-2 = RHIGH is two months before MWM; 3 =
RHIGH is three months after MWM)
CMAT
Calculated mean annual temperature (C)
CRR
Calculated real rainfall (mm) – annual total
WSTORAGE Amount of water which can be stored in the soil (mm)
Calculations of Water Balance and Derived Variables, Including those
Relating to Plant Productivity
ET
Effective Temperature (following Bailey) [14 is the mean value for
the world-- tropics range up to 26, polar regions down to 8 or so]
PET
Potential evapotranspiration (mm) – amount of water which could
be evaporated by incoming solar radiation over a year
SNOWAC Annual snow accumulation (mm of water)
WRET
Annual average water retention in the soil (mm)
PERWRET Percent of months in the growing season with water retention in the
soil
AE
Actual evapotranspiration (mm) – amount of water which is
evaporated given both annual incoming solar radiation and
precipitation amounts
RUNOFF
Annual amount of runoff (mm) - water in excess of the amount
which can be stored in the soil or evaporated
WATD
Water deficit (mm) – difference between the amount of water which
could be evaporated and stored in the soil and the water which is
available
MI
Moisture index – continuous scale negative values indicate drier
settings, positive values indicate wetter settings (following
Thornwaite & Mather 1955)
BT
Biotemperature (C) – measure of central tendency of temperature
which divides the sum of mean temperatures for months with mean
> 0 by 12 (following Holdridge 1947)
GROWC
Count of months in the growing season
WLTGRC
Number of growing season months with little enough rainfall plants
will wilt
WATDGRC Number of growing season months with a water deficit
WATRGRC Number of growing season months in which water is retained in the
soil
RUNGRC
Number of growing season months with sufficient precipitation to
produce runoff
PGROW
Plant growth potential – scale is 0-36 with 36 indicating settings
with sufficient solar radiation and rainfall for plants to grow well in
every month (values for each month range from 0-3 with – 0
indicates insufficient solar radiation, 1 indicates plants past wilting
point, 2 indicates months with a water deficit, 3 indicates months
with enough of both solar radiation and water in the soil)
SDTEMP
Standard deviation of the monthly temperature values
CVTEMP
Coefficient of variation of the monthly temperature values
SDRAIN
Standard deviation of the monthly precipitation values
CVRAIN
Coefficient of variation of the monthly precipitation values
RRCORR2
Adjusted correlation between month of peak temperature and
month of peak rainfall [=RRCORR +4.5 such that when peak
temperature and peak rainfall are in same month, RRCORR2=4.6]
RRCORR3 Collapsed adjusted correlation between month of peak temperature
and month of peak rainfall [If GROWC=12 then RRCORR3= 4.6;
else RRCORR3=RRCORR2]
SEASON
Ordinal code of the season of peak rainfall (1=spring, 2=summer,
3=autumn, 4=winter) calculated from values of RRCORR
BIO5
Standing biomass of the plant community (g/m2)
BAR5
Biomass accumulation ratio – new cells of standing biomass added
each year – low values indicate deserts, grasslands, high values
indicate forests
NAGP
Net above ground productivity (g/m2/yr) – new cells of above
ground plant material (stems, leaves; not roots) added each year
TEMP
Temperateness – low values indicate highly seasonal climates;
high values indicate climates with less seasonal variability
HIRX
Rainfall Index – [PET/CRR] (following Holdridge 1959; similar to
Holdridge 1947) values < 1 indicate environments which can
support forests, values > 1 indicate arid plant communities
RRANGE
Range (mm) of mean monthly precipitation values
TRANGE
Range (C) of mean monthly temperature values
REVEN
Evenness of mean monthly precipitation values
MRAIN
Meanness of mean monthly precipitation values
MTEMP
Meanness of mean monthly temperature values
PTOAE
Ratio of Potential evapotranspiration to Actual evapotranspiration
(PET/AE)
PTOWATD Ratio of Potential evapotranspiration to Water deficit (PET/WATD)
PTORUN
Ratio of Potential evapotranspiration to Runoff (PET/RUNOFF)
PTOWATR Ratio of Potential evapotranspiration to Water retention in the soil
(PET/WRET)
PERWLTG Percentage of months in the growing season with little enough
water retention that plants will wilt
PERWDEF Percentage of months in the growing season with a water deficit
Scale = 0-1
DEFPER
Percentage of months in the growing season with a water deficit
Scale = 0-100 (DEFPER=100*PERWDEF)
AVWAT
Ordinal scale of water availability (low = drier; high = wetter)
Variables which summarize environmental characteristics
CLIM
Ordinal scale of climate (low = colder; high= warmer)
CLASS
Wet/ Dry classification
MEDSTAB Mediterranean stability – highest values indicate dry regions with
winter rainfall
SUCSTAB Successional stability – highest values indicate regions where
summer thunderstorms could ignite fires
SUCSTAB2 Successional stability 2 – revised version of SUCSTAB: highest
values indicate regions likely to have a fire maintained landscape –
hot dry summers with intermittent thunderstorms; includes terms
monitoring fuel availability
WACCESS Water stored in the soil which is accessible to plants
Log variables
L+Variable Name: Log10 of (Variable Name) : [LLAT, LBIO5, LNAGP,
LMEANELV, LET, LPET, LAE, LBT, LTRANGE, LCMAT, LMCM,
LMWM, LMTEMP, LCVTEMP, LCRR, LREVEN, LRRCORR2,
LRRCORR3, LRRANGE, LDEFPER, LPERWDEF, LPTOAE,
LRUNOFF, LRHIGH, LRLOW, LCOKLM, LPERWLTG, LSNOWAC,
LWACCESS, LPTORUN, LRUNGRC, LWRET, LWLTGRC, LBAR5,
LMRAIN, LWATD, LCVRAIN, LPTOWATD, LPTOWATR,
LWATRGRC, LHIRX, LSSTAB2]
Projected Ungulate Biomass
EXPREY
Expected prey biomass g/m2 – ungulate biomass projected from
regression equation using environmental variables to calculate
value run on 104 cases with recorded ungulate biomass
LEXPREY Log10 of EXPREY
Hunter-Gatherer Projections (Subsistence and Density)
WSUM
Sum of the initial projections of dependence on hunting, gathering
and fishing – the closer this value is to 100, the less the values of
WHUNTP, WGATHP, WFISHP were adjusted through iteration
(used to assess when to be more cautious about projections – my
rule of thumb is that if this value is < 80 or > 120, I’m more cautious
about using the HG projected subsistence)
WHUNTP
Projected hunter-gatherer dependence on terrestrial animals (% of
diet)
WGATHP
Projected hunter-gatherer dependence on terrestrial plants (% of
diet)
WFISHP
Projected hunter-gatherer dependence on aquatic resources (% of
diet) [aquatic resources include fish, shellfish, marine mammals
and aquatic birds]
SUBSPE
Expected subsistence specialty – codes the dominant resource in
the diet [1=terrestrial animals; 2=terrestrial plants; 3=aquatic
resources]
WDEN1
Projected hunter-gatherer population density calculated for all 339
HG cases
WDEN2
Projected hunter-gatherer population density calculated for only
142 HG cases in the proportional sample [selected as proportional
sample of area of the earth covered by different vegetation types]
WDEN
Projected hunter-gatherer population density – calculated as
average of WDEN1 & WDEN2
Terrestrial Model Variables [See Binford 2001 for discussion of Terrestrial
Model]
TERMH2
Terrestrial Model Hunting Density: number of people per 100 sq km
who could be supported by subsistence on terrestrial animals
TERMG2
Terrestrial Model Gathering Density: number of people per 100 sq
km who could be supported by subsistence on terrestrial plants
TERMD2
Terrestrial Model Density (people per 100 sq km): sum of TERMH2
and TERMG2
TERMHNT2 Terrestrial Model Percent Dependence on Hunting
TERMGTH2 Terrestrial Model Percent Dependence on Gathering
EDENH22 Portion of projected hunter-gatherer population density which would
be supported by hunting terrestrial animals
[=WDEN *(TERMHNT2/100)]
EDENG22 Portion of projected hunter-gatherer population density which would
be supported only by gathering terrestrial plants
[=WDEN *(TERMGTHT2/100)]
Expected value of population pressure index [WDEN/TERMD2] –
TERMD2 is used as a baseline population density that could be
supported without cultural aids in a given environmental setting; By
dividing projected hunter-gatherer population density by the
terrestrial model density, we get a value that tells us how many
times higher the expected hunter-gatherer density is than the
terrestrial model density. This could be used to indicate the degree
of population pressure on the resources (particularly relevant for
terrestrial resources – see below).
EPHNDX22 Expected value of population pressure index specific to terrestrial
animal resources [EDENH22/(TERMH2+.01)]
EPGNDX22 Expected value of population pressure index specific to terrestrial
plant resources [EDENG22/(TERMG2 +.01)]
SUBSPX
Terrestrial Model Subsistence Specialty [h=hunting, g=gathering,
m=mixed (45-55 percent of each), u=uninhabited (if TERMD2 < .3
persons per 100 sq km)]
EPRINDX2
More Hunter-Gatherer Projections (Body mass, area, total population,
number of moves, distance moved, group sizes, family size, house sizes &
density controlled subsistence dependence)
EXWGT2
Projected average weight (kg) of adult males (variable by
environmental setting)
For the following suite of variables, the equations to project hunter-gatherer
organizational variability were calculated on subsets of the 339 case file defined
by group mobility pattern [GRPPAT: 1=residentially mobile, 2=fairly sedentary]
and subsistence specialty [SUBSP: 1=hunting, 2=gathering, 3=fishing].
EXAREA1
Projected area occupied by hunter-gatherers who are residentially
mobile throughout the year.
EXAREA2 Projected area occupied by hunter-gatherers whose primary
residences are stable during the year.
EXTLPOP1 Projected total population of an ethnic group for hunter-gatherers
who are residentially mobile throughout the year.
EXTLPOP2 Projected total population of an ethnic group for hunter-gatherers
whose primary residences are stable during the year.
EXNOMOV1 Projected number of moves per year for hunter-gatherers who are
residentially mobile throughout the year.
EXNOMOV2 Projected number of moves per year for hunter-gatherers whose
primary residences are stable during the year.
EXDMOV1 Projected distance moved (mi) hunter-gatherers who are
residentially mobile throughout the year.
EXDMOV2 Projected distance moved (mi) by hunter-gatherers whose primary
residences are stable during the year.
See Binford 2001 for distinctions between how GRP1, GRP2, GRP3 are
measured for GRPPAT 1 vs GRPPAT 2.
EXGRP1
HG Projected size of either the smallest autonomous residential
unit during a year (GRPPAT =1) or the smallest settlement size in a
region (GRPPAT =2)
EXGRP2
HG Projected size of either the largest interdependent residential
unit during a year (GRPPAT=1) or a mid-range settlement size in a
region (GRPPAT =2)
EXGRP3
HG Projected size of either the largest periodic aggregation
(GRPPAT =1) or the largest settlement size in a region
(GRPPAT=2)
EXMHS
Projected Mean Household Size (persons) for hunter-gatherers
EXSZMEAN Projected size of the average house (measured as the diameter of
a circle (m) which would have an area equivalent to the mean
house area)
EXSZ1FAM Projected size of the average single family house for huntergatherers (measured as the diameter of a circle (m) which would
have an area equivalent to the mean house area)
The following variables are calculated just as WHUNTP, WGATHP, and WFISHP
are calculated except that instead of using WDEN as an input variable, these
equations control the values of population density.
UPHUNTP Unpacked HG (density < 9.09 persons per 100 sq km) percent
dependence on hunting (terrestrial animals)
UPGATHP Unpacked HG (density < 9.09 persons per 100 sq km) percent
dependence on gathering (terrestrial plants)
UPFISHP
Unpacked HG (density < 9.09 persons per 100 sq km) percent
dependence on fishing (aquatic resources)
D1PHUNTP Packed HG (density =9.09 persons per 100 sq km) percent
dependence on hunting (terrestrial animals)
D1PGATHP Packed HG (density =9.09 persons per 100 sq km) percent
dependence on gathering (terrestrial plants)
D1PFISHP Packed HG (density =9.09 persons per 100 sq km) percent
dependence on fishing (aquatic resources)
D1HPHUNTP HG density 1.5 times “packing threshold” (density = 13.635
persons/ 100 sq km) percent dependence on hunting (terrestrial
animals)
D1HPGATHP HG density 1.5 times “packing threshold” (density = 13.635
persons/ 100 sq km) percent dependence on gathering (terrestrial
plants)
D1HPFISHP HG density 1.5 times “packing threshold” (density = 13.635
persons/ 100 sq km) percent dependence on fishing (aquatic
resources)
D2PHUNTP HG density 2 times “packing threshold” (density = 18.18 persons/
100 sq km) percent dependence on hunting (terrestrial animals)
D2PGATHP HG density 2 times “packing threshold” (density = 18.18 persons/
100 sq km) percent dependence on gathering (terrestrial plants)
D2PFISHP HG density 2 times “packing threshold” (density = 18.18 persons/
100 sq km) percent dependence on fishing (aquatic resources)
D2HPHUNTP HG density 2.5 times “packing threshold” (density = 22.725
persons/ 100 sq km) percent dependence on hunting (terrestrial
animals)
D2HPGATHP HG density 2.5 times “packing threshold” (density = 22.725
persons/ 100 sq km) percent dependence on hunting (terrestrial
plants)
D2HPFISHP HG density 2.5 times “packing threshold” (density = 22.725
persons/ 100 sq km) percent dependence on hunting (aquatic
resources)
D3PHUNTP HG density 3 times “packing threshold” (density = 27.27 persons/
100 sq km) percent dependence on hunting (terrestrial animals)
D3PGATHP HG density 3 times “packing threshold” (density = 27.27 persons/
100 sq km) percent dependence on gathering (terrestrial plants)
D3PFISHP HG density 3 times “packing threshold” (density = 27.27 persons/
100 sq km) percent dependence on fishing (aquatic resources)
Growth Rate Model Variables
The rest of the variables are from an extra program which uses environmental
variability to model differences in growth rate – based on terrestrial model density
as an indication of abundance and accessibility of resources which is tempered
by model with higher pathogen loads where it is warmer and wetter and lower
pathogen loads where it is cooler/ dryer (using data accumulated by Bobbi Low)
TMREPPOT Terrestrial Model Reproductive Potential (without considering
pathogens)
REPRATE
Reproductive Rate (factoring pathogen load in)