Eric Keys

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Thousands of Years of Environmental Change in the
Southern Yucatan

• Eric Keys
• Department of Geography
• Arizona State University
• eric.keys_at_asu.edu

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THIS is the forest primeval. The murmuring pines
and the hemlocks, Bearded with moss, and in
garments green, indistinct in the twilight,
Stand like Druids of eld, with voices sad and
prophetic, Stand like harpers hoar, with beards
that rest on their bosoms. -Longfellow
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But what is missing from these slides?
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1492

• For generations of our people time in the
  Americas began in 1492
• Recent science demonstrates that in fact 1491 and
  before were very active times in the Americas
• The New World moniker should be questioned

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Into the Americas

• CW states that people crossed into the Americas
  about 13,000 BP
• Used Bering Land Bridge
• Timing in serious contention these days
• Some of the earliest cities anywhere if current
  archaeology is correct

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Linguistic Diversity
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Centers of Crop Domestication
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The Southern Yucatan Peninsular Region
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Seasonal Tropical Forest
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First Millennium Long-Wave
Maya entry deforestation
1000 BC
AD 900
AD 1880
AD 1500
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1000 BCEEarly Settlement
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The Landscape of Domestication

• Gardens likely candidate for the domestication of
  species
• Collection, protection, selection, domestication
• House gardens ubiquitous in Maya area
• Managed by women and children

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Maize Essence of the Mayab
Cucuribits
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Coa or Dibble Stick
Mesoamerican Trinity
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300 CEEarly Urbanism
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Vegetation change
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Swidden Agriculture

• -Patches cut out of forest
• -Allowed to dry
• -Burned before the
• rainy season
• -Provides nitrogen to soils
• -Limits weeds and pests

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Swidden Farmers

• Ancient system
• Use axe, hoe, fire
• Very little reaches market
• Largely for subsistence
• Good for low-population density

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Swidden (Rotational) Farming
2 Year Snapshots
20 ha (2.47 acres) 1 ha plots
Year 0
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Swidden (Rotational) Farming
20 ha (2.47 acres) 1 plot of 1 ha
Year 2
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each
Year 4
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 1 plots
in young succession
Year 6
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 2 plots
in young succession
Year 8
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 3 plots
in young succession
Year 10
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 4 plots
in young succession
Year 12
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 5 plots
in young succession
Year 14
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 6 plots
in young succession
Year 16
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 7 plots
in young succession
Year 18
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession
Year 20
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 1 plot in old succession
Year 22
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 2 plots in older succession
Year 24
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 3 plots in older succession
Year 26
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 4 plots in older succession
Year 28
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 5 plots in older succession
Year 28
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 6 plots in older succession
Year 30
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 7 plots in older succession
Year 32
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 8 plots in older succession
Year 34
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 8 plots in older succession
Year 34
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 9 plots in older succession
Year 34
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Swidden (Rotational) Farming
20 ha (2.47 acres) 2 plots of 1 ha each 8 plots
in young succession 9 plots in older succession
Year 34
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400 CEPreclassic City
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700 CEClassic City
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900 CELate Classic City
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Central Maya Lowlands Landscape, circa AD 850
Managed forest
Plazuelas
Minor ceremonial center
Nucleated settlement
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Copan Reconstruction
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14th CenturyReturn of the Forest
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Collapse

• Between 700-900 CE the Maya lowland cities
  rapidly depopulated
• Reasons not fully known
• Varied
• Climate?
• Environmental change?
• War?
• Trade?
• Collapse debatable

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Maya Impacts on Forest
Pet kot
Brosimum alicastrum L. ramón
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The Study Area
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Modern HistoryStart of Second Long Wave?
Episode of Forest Extraction
1880
1894
1901
1934
1955
1970
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Chicle Concessions Extraction
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Timber Concessions, circa 1920
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Logging 1950-70s Mahogany Swietnia macrophylla
King. Spanish Cedar Cedrella odorata L.
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Hardwood Extraction, Post WW II
Before 1960-Study Region Logging, 1900-1930
26,400 mahogany trees (70,400 m3) Logging,
1930-1960 93,633 mahogany trees (250,000 m3)
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Hardwood Extinction

• Lundell, Standley, Miranda ? abundant hardwoods
  in region
• Of 119 tree species in mature upland forests, S.
  macrophylla and C. odorata rank 56 and 92,
  respectively
• No species had dbh 40 cm!

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Modern HistorySecond long Wave?
Government sponsored, large projects
settlement, rice projects, cattle schemes
Forest extraction
Immigration big projects
1880
1894
1901
1934
1955
1967
1989
1982
1993
Hurricane Janet
Debt crisis
Oil boom
Rt. 186
Calakmul biosphere reserve
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Forest Cover Change, 1987-1997
Def 6.31 Ref 6.5
Def 13 Ref 3.6
Deforestation 16 Reforestation 5
Def 16 Ref 5
Chili zone 3,300 sq. km. 16 deforestation (net
11) 3 x Regional Average
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Major Immigration 1967 thru 1985
bosque mediano
new cut
succession
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Population Change
Ancient Maya 100-150 people/km2 uplands only
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Episode of Big Projects 1970-85
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Chile/Chili
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Smallholder Intensification and Diversification
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Sign of Degradation ?
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Bracken in SYPR
1987 ? 19 km2
1997 ? 92 km2
10 km
Wetland Forest Upland Forest Bracken Fern
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Land Change
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Calakmul Biosphere Reserve Biological Corridor
Established 1989 UN accepted 1993
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El Mundo Maya
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