Vietnam War: Forest Fire as a Military Weapon - Paperless Archives

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I Fireclimate Classification SECRET If the decision is reached to include forest fire operations as part of the planned military strategy, then a full-scale climatic analysis should be made in order to determine the probable ground fuel accumulations by forest types and define the need and timing requirements for special desiccation treatments. Climatologists have divided the climates of the world into natural groups that describe the airmasses responsible for the various climates. The major climate groups are subdivided, almost without limit, as needed to describe more precisely each local situation. The classifications presented by the different authors are rather complex. They are useful for many purposes, as in studies of natural vegetation and soil formation, and in determining potential use of crop plants. But none are directly applicable in planning the use of fire in forests. A fireclimate classification must distinguish among the myriad temperature-precipitation combinations for their effects on forest burning conditions and on plant growth. Temperature Regimes: The fireclimate temperature classification is based on severity of winter weather as a means of showing the season when air temperature restricts plant growth regardless of soil moisture conditions, and'to shuw the seasons when plants grow and mature. Drying of natural fuels is geared to these seasons; and treatments aimed at desiccating green vegetation must be timed to fit the seasons. Winter weather is defined by average monthly mean temperature (one half the sum of average maximum and average minimum daily temperatures for the month) and by average monthly lowest temperature (sum of lowest temperature recorded each year for the month divided by number of yars of record). Both the mean temperature and the monthly lowest are averag's for the 3 coldest months. This procedure eliminates consideration of occasional extremely low temperatures which are relatively unimportant in growth of native forest vegetation. The six winter temperature regimes are: Winter severity Average temperature for coldest 3 months Daily Monthly means lowest j (OF) (OF) Frostfree (FF) 61, 48, or higher or higher Mild (MI) 51-60 26-46 Cool (CL) 41-50 16-25 Short, cold (SC) 31-40 1-15 Long, cold (LC) 21-30 -15-0 Very cold (VC) 20, -16, or lower or lower I NOTE: If a borderline location fits into 2 different temperature classes (For example, mean 500 and lowest 270) the classification is set by the coldest class (above example = cool winter, CL). .SECRET 33
Precipitation Regimes: SECRET The fireclimate precipitation classes show: (i) the relative length and intensity of the dry season havingweather suitable for burning, and (2) the relative amount and frequency of rainfall during that portion of the non-burn season having temperatures favorable for plant growth. Four lengths of burn season are recognized: none, short, long, and yearlong. The non-burn portion of the year is classed as either humid or nonhumid. The distinction between a humid and a nonhumid month commonly is made by comparing average precipitation of the month with the potential evapotranspiration for the month. Potential evapotranspiration-a concept introduced by Thornthwaite _2/is the estimated amount of water needed for both evaporation losses and plant transpiration losses from a vegetation-covered land surface, assuming that plant growth is not inhibited by water shortage. Papadakis has published monthly potential evapotranspirational losses for 2400 locations over the world. INThe monthly loss can be approximated from average maximum daily temperature and average afternoon relative humidity as shown by the curves in Figure 28, which were adapted from the Papadakis data. Months with average precipitation equal to or greater than estimated potential evapotranspiration are considered humid, designated as "H". Papadakis has described a dry month, designated as "D", as one in which water stored in the soil during previous humid months plus average precipitation of the month together equal less than one half of the estimated potential evapotranspiration for the month. Maximum water storage capacity of th.. soil is assumed to be 3.9 inches of water. At most locations a few months of the year are intermediate between humid and dry. The data obtained during calculation of the burning odds at any location-as illustrated in Table 4-also can be used to designate months of adequate precipitation and months of moisture stress. For example, "H" months always show positive (+) values from Figure 27: and "D" months, with few exceptions, are also burn months, designated as "B", which have negative (-) values. In addition, the driest of the intermediate months are apparent because they have negative (-) values, which usually are small. By combining length of burn season and adequacy of precipitation during the non-bum season, the 7 fireclimate precipitation regimes are: Humid yearlong (HUYL)-No "B" months and no (-) values; yearly (+) values from a minimum of 200 down to 50, depending on temperature regimes as shown in Table 5. These locations have no "D" months, and usually have 6 to 12 "H" months. Nonhumid. no burn season (NHYL)-No "B" months and no "D" months; but otherwise not in the humid class (see Table 5). Humid, short bum season (HUSB)- 1-4 "B" months, with yearly (-) values of 1-25; (for yearly (+) values see Table 5). Most locations have 4 to 10 "H" months 0 to 4 "D" months. Nonhumid, short burn season (NHSB)- 1-4 "B" months, with yearly (-) values of 1-25; yearly (+) values too low for humid (see Table 5). 12! Thornthwaite, C. W. An approach towards a rational classification of climate. Geogr. Rev. XXXVIII, pp. 55-94. 1948. 1_J3 Papadakis, J. Climatic tables for the world. Published by the author Cordoba 4564, uenos Aires, Argentine. 1961. SECRET 34
Page 1: VIETNAM WAR Forest Fire as a Milita
Page 4 and 5: Forest Fire as a Military Weapon A
Page 6 and 7: OF7 A iD5S Hil'---0 __ = IIIII- _w
Page 8 and 9: SECRET FOREST FIRE AS A MILITARY WE
Page 10 and 11: SECRET INDEX (Continued) Page Weath
Page 12 and 13: SECRET FOREST FIRE AS A MILITARY WE
Page 14 and 15: SECRET detailed and timely intellig
Page 16 and 17: SECRET I I I i it FI.I FIG. 2 I I B
Page 18 and 19: I SECRET I I I I I S....... '•FIG
Page 20 and 21: SECRET FI.I TYIAIRONFR BEOR FIG.FIG
Page 22 and 23: SECRET REQUIREMENTS FOR SUCCESSFUL
Page 24 and 25: I I SECRET heating adjacent unburne
Page 26 and 27: I SECRET FUEL TYPE 8o e1 82 83 84 I
Page 28 and 29: I SECRET I ii 11 I S~FIG. 17 | GRAS
Page 30 and 31: I I SECRET I I FIG. 18 SHRUB TYPE I
Page 32 and 33: Relative Humidity SECRET Table 2 "S
Page 34 and 35: I U I I I I I SECRET I FIG. 21 CONI
Page 36 and 37: S~SECRET A I. B O I I I IB. IN O LE
Page 38 and 39: I I SECRET I- I I I I I I I FIG. EV
Page 40 and 41: SECRET In developing recommended pr
Page 42 and 43: U SECRET The yearly sums of (+) val
Page 46 and 47: SECRET TABLE 5 KEY TO IDENTIFICATIO
Page 48 and 49: SECRET SHumid, long bum season (HUL
Page 50 and 51: I SECRET Table 6 Surfac,,/Volume Ra
Page 52 and 53: I SECRET FIG. 29 AVAILABLE FUEL WEI
Page 54 and 55: SECRET 100 80 FIG. 31 FLAME HEIGHTS
Page 56 and 57: I SECRET I Table 7 Precipitation Ef
Page 58 and 59: I SECRET FIG. 32 EQUILIBRIUM MOI$TU
Page 60 and 61: •Sunshine: SECRET Solar radiation
Page 62 and 63: I I SECRET I Ii I II I g I FIG. 34
Page 64 and 65: Technique"s for Kdlin, D•rming an
Page 66 and 67: SECRET I t '4Pi I I FIG. 35 * AERIA
Page 68 and 69: SECRET FIG.36 EFFECTS OF OVERSTORY
Page 70 and 71: SECRET FIG. 37 TYPICAL EFFECT OF CO
Page 72 and 73: I .SECRET Use of Systemic Desiccant
Page 74 and 75: SECRET 6. Effectiveness of foliar s
Page 76 and 77: SECRET Example of a Desiccation Pla
Page 78 and 79: SECRET If a lighted match is droppe
Page 80 and 81: SECRET 0 0 ----- 0" E I- -- z -- o
Page 82 and 83: SECRET The advantages of multiple i
Page 84 and 85: SECRET DISCUSSION The deliberate in
Page 86 and 87: 1 SECRET U MINH FOREST FIRES PROLOG
Page 88 and 89: SECRET Spread Analysis: Spread to K
Page 90 and 91: SECRET HEADQUARTERS US ARMY ADVISOR
Page 92 and 93: I SECRET MACV-IVC-2 24 May 1968 SUB
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SECRET NAVAL GUNFIRE MISSIONS DATE
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SECRET Rach Gia - Kien Giang Hourly
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SECRET APPENDIX B Pertinent Incendi
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SECRET Major vegetation type: Tropi
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SECRET CLIMATE FF-HUSB FROSTFREE WI
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SECRET FIG. B2 CLIMATE FF-HUSB HANO
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SECRET Soil appiicat ion: Apply 20
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SECRET CLIMATE FF-NHLB FROSTFREE WI
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SECRET CLIMATE FF-DRYL FROSTFREE WI
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SECRET CLIMATE MI-HUYL MILD WINTER;
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SECRET FIG. B6 CLIMATE MI-HUYL NEW
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SECRET Soil application: Apply 15 p
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SECRET CLIMATE MI-HULB MILD WINTER;
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SECRET FCa. W8 CLIMATE MI-HULB RHOD
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SECRET FIG. B9 CLIMATE MI-NHSB AUST
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SECRET Dates for examl ocationAU.s
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SECRET CLIMATE MI-DRYL MILD WINTER;
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* climates& j SECRET CLIMATE CL-HUY
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SECRET FIG. 512 CLIMATE CL-HUYL COL
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SECRET Dates for example location (
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SECRET t (IIMATI (L HILD ('(X)I WIN
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SECRET (1lMAU- (L NH.% 41()1. *INTI
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I SECRET (IIM-AIF ( Hl•Nt1 ( Wl W
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SECRET FIG. 816 CLIMATE CL-NHLB GRA
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SECRET FIG. 817 CLIMATE CL-DRYL LAS
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Foliar sTray: Apply per acre: SECRE
Page 146 and 147:
Warm continental climates SECRET CL
Page 148 and 149:
SECRET FIG. B19 CLIMATE SC-HUSB MT.
Page 150 and 151:
SECRET Dates for cxampre location (
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SECRET CLIMATE SC-NHYL SHORT COLD W
Page 154 and 155:
SECRET FIG. B21 CLIMATE SC-NHYL PAR
Page 156 and 157:
SECRET FIG. 522 CLIMATE SC-NHSB SAN
Page 158 and 159:
SECRET FIG. 823 CLIMATE SC-NHLB REN
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SECRET Foliar Žpxa: Apply per acre
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SECRET CLIMATE LC-HUSB LONG COLD WI
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SECRET Foliar spray: Apply during t
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"SECRET CLIMATE LC-NHLB LONG COLD W
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SECRET CLIMATE VC-HUYL VERY COLD WI
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I SECRET FIG. 827 CLIMATE VC-HUYL D
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SECRET "CLIMATE VC-NHSB VERY COLD W
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SECRET I Publiction-,: Protect EMOT
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