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Contrasting Vegetation and Fire Histories on the Point Reyes Peninsula During the Pre-Settlement and Settlement Periods R. SCOTT ANDERSON Environmental & Quaternary Sciences Northern Arizona University Flagstaff, Arizona
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Scott Anderson 2-2-06 - NPS

Feb 04, 2022

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Page 1: Scott Anderson 2-2-06 - NPS

Contrasting Vegetation and Fire Histories on the Point Reyes Peninsula

During the Pre-Settlement and Settlement Periods

R. SCOTT ANDERSONEnvironmental & Quaternary Sciences

Northern Arizona UniversityFlagstaff, Arizona

Page 2: Scott Anderson 2-2-06 - NPS

Primary Collaborator:Peter Brown (RMTRR)

Supported by:National Park Service

(Point Reyes National Seashore)

Page 3: Scott Anderson 2-2-06 - NPS

Outline of Talk

• Introduction to Paleoecological Research• Physical Setting of the Study Sites• Vegetation & Fire Histories

– Previous Research– Present Research

• Comparison with Other Sites along Coastal California

• General Considerations & Conclusions

Page 4: Scott Anderson 2-2-06 - NPS

How do paleoecologists collect data?

Obtain Sediment Cores from Lakes, Bogs, Wetlands

Isolate Pollen, Plant Macrofossils & Charcoal

Compare Fossil Datasets to Modern Datasets

Page 5: Scott Anderson 2-2-06 - NPS

Sediment Coring – Lakes & Bogs

Page 6: Scott Anderson 2-2-06 - NPS

“Tools” of the Paleoecologist

Page 7: Scott Anderson 2-2-06 - NPS

“Tools” of the Paleoecologist: Pollen Macrofossils

Page 8: Scott Anderson 2-2-06 - NPS

http://www.geo.arizona.edu/palynology/geos462/29charcoal.html

http://nrg.ncl.ac.uk/people/staff/tyson/gallery/gal11.html

“Tools” of the Paleoecologist:Charcoal Particles

Microscopic Charcoal

Macroscopic Charcoal

Page 9: Scott Anderson 2-2-06 - NPS

Charcoal Production & Transport

Production

Transport

Deposition

+

Production & Transport, Clockwise from upper left: http://www.atmos.umd.edu/~zli/Info/crown_fire-copy%20copy.jpg; http://www.fs.fed.us/rm/hayman_fire/text/03romme/03_fig11.html; http://www.wapa.gov/media/cct/sept6/images/hayman4.jpg; http://www.kwphoto.com/Resources/Images/94_0007-20.jpg

Page 10: Scott Anderson 2-2-06 - NPS

Limitations of Paleoecology

• Not all species are preserved as fossils• Not all body parts are preserved as fossils

Biocoenosis (life assemblage)

versus

Thanatocoenosis (death assemblage)

Page 11: Scott Anderson 2-2-06 - NPS

How do we age the sediments?Radiometric dating

14C = range up to 40,000 years ago210Pb = range up to 150 years ago

137Cs = 1964 AD peak in bomb testing

Comparison with known historical events

Comparison with known fires

Page 12: Scott Anderson 2-2-06 - NPS

History of Settlement & Use of Pollen for Dating

1817 - Spanish influence commenced here by establishment of San Rafael Franciscan mission (Brown et al.1999)

After 1821 - Point Reyes opened to land claims, with the first granted in 1836 in the Olema Valley

The area was subsequently opened for grazing and dairy ranching (Livingston 1994, 1995)

The settlement period identified by increases in pollen indicators of grazing and land disturbance (i.e., dock [Rumex], plantain [Plantago], filaree[Erodium]), planted trees (Eucalyptus)

Page 13: Scott Anderson 2-2-06 - NPS

Paleoecological Research at PORE –3 Previous Studies

• Rypins et al. 1989 - Coast Trail Pond plus stratigraphic sections

– 12,300 14C-yr record, begins w/ Douglas-fir – fir forest– 10,300 to 9,400 14C yr ago transition to coastal sage scrub and

grassland • Russell 1983 - Wildcat Lake

– 900 yr record (?)– Suggested alternation of importance of grassland and sage

scrub vegetation– Charcoal concentration less above ca. 35 cm depth (age?)

• Duncan 1992 - Mud Pond– 1000 yr record– vegetation and ethnobotanical uses of plants by the Miwok at the

time of European contact

Page 14: Scott Anderson 2-2-06 - NPS

Terminology(Ages Approximate)

• Late Pleistocene = prior to 11,500 years ago

• Holocene = since 11,500 years ago– Early Holocene = to 7000 years ago– Middle Holocene = 7000 to 4500 years ago– Late Holocene = 4500 years ago to 1850 AD– Settlement Period = after 1850 AD

Page 15: Scott Anderson 2-2-06 - NPS

5000

1000015000200002500030000

3500040000

45000500005500060000

65000

Age

200

300

400

500

600

700

800

900

1000

Dep

th

20 40

CYPRESS Family

100 200 300 400

PINE (a

ll typ

es)

20

DOUGLAS-FIRFIR

20 40 60

SEQUOIA

OAKTANOAKALD

ER

20

COYOTE BRUSH &

Othe

rsLaguna de las Trancas (near Santa Cruz)

The Last 65,000 Years Along the Coast

Page 16: Scott Anderson 2-2-06 - NPS

Studies Sites on Point Reyes

• Coast Trail Pond• Glenmire

• Creamery Bay Bog• Wildcat Lake

• Shutter Ridge Pond

Page 17: Scott Anderson 2-2-06 - NPS

Why Choose These Sites?

• Examined a variety of wet areas• Chose Sites from:

–Range of vegetation types–Over an elevational gradient

Page 18: Scott Anderson 2-2-06 - NPS
Page 19: Scott Anderson 2-2-06 - NPS

Coast Trail Pond• 230 m above sea

level• Coastal scrub near

closed forest• Little historical data

exists on the history of grazing at this site

• Oldest site in our study

Page 20: Scott Anderson 2-2-06 - NPS

Coast Trail Pond

Page 21: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

Dep

th c

m

10002000300040005000600070008000

9000

10000

11000

12000

1300014000150001600017000

Age

Cal

yr B

P

12260 ±110

9040 ± 40

7100 ± 50

1850 AD

1963 AD

Dat

es

20

FIR

20 40

PiINE

20

DOUGLAS-FIR

SEQUOIA20

ALDEROAK

20

SAGEBRUSH

20

Other Sage S

crub Taxa

20 40 60

COYOTE BRUSH &

Oth

ers

20406080

GRASS

204060

SEDGE

20

WATER FERNFILAREEEUCALYPTUS

GOOSEFOOT

20

DOCKPLANTAINSPORORMIELLA

Coast Trail Pond - Trees, Shrubs, Herbs, Wetland

Forest and Sage Scrub

Page 22: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

Dep

th c

m

10002000300040005000600070008000

9000

10000

11000

12000

1300014000150001600017000

Age

Cal

yr B

P

12260 ±110

9040 ± 40

7100 ± 50

1850 AD

1963 AD

Dat

es

20

FIR

20 40

PiINE

20

DOUGLAS-FIR

SEQUOIA20

ALDEROAK

20

SAGEBRUSH

20

Other Sage S

crub Taxa

20 40 60

COYOTE BRUSH &

Oth

ers

20406080

GRASS

204060

SEDGE

20

WATER FERNFILAREEEUCALYPTUS

GOOSEFOOT

20

DOCKPLANTAINSPORORMIELLA

Coast Trail Pond - Trees, Shrubs, Herbs, Wetland

Sage Scrub w/ Forest – Driest

Period

Page 23: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

Dep

th c

m

10002000300040005000600070008000

9000

10000

11000

12000

1300014000150001600017000

Age

Cal

yr B

P

12260 ±110

9040 ± 40

7100 ± 50

1850 AD

1963 AD

Dat

es

20

FIR

20 40

PiINE

20

DOUGLAS-FIR

SEQUOIA20

ALDEROAK

20

SAGEBRUSH

20

Other Sage S

crub Taxa

20 40 60

COYOTE BRUSH &

Oth

ers

20406080

GRASS

204060

SEDGE

20

WATER FERNFILAREEEUCALYPTUS

GOOSEFOOT

20

DOCKPLANTAINSPORORMIELLA

Coast Trail Pond - Trees, Shrubs, Herbs, Wetland

Sage Scrub w/ Mixed Hdwds &

Conifers

Page 24: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

Dep

th c

m

10002000300040005000600070008000

9000

10000

11000

12000

1300014000150001600017000

Age

Cal

yr B

P

12260 ±110

9040 ± 40

7100 ± 50

1850 AD

1963 AD

Dat

es

20

FIR

20 40

PiINE

20

DOUGLAS-FIR

SEQUOIA20

ALDEROAK

20

SAGEBRUSH

20

Other Sage S

crub Taxa

20 40 60

COYOTE BRUSH &

Oth

ers

20406080

GRASS

204060

SEDGE

20

WATER FERNFILAREEEUCALYPTUS

GOOSEFOOT

20

DOCKPLANTAINSPORORMIELLA

Coast Trail Pond - Trees, Shrubs, Herbs, Wetland

Historic Period

Page 25: Scott Anderson 2-2-06 - NPS

Glenmire• 167 m above sea level• Wetland NW of Glen

Campground• Closed Douglas-fir forest

with California bay and oak

• Part of the Shafter Ranches, South End Tract (Livingston 1994). By 1879 a thriving dairy farm

• Cored in 30 cm of water

Page 26: Scott Anderson 2-2-06 - NPS

Glenmire

Page 27: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

Dep

th c

m

0

1000

2000

3000

4000

50006000700080009000

10000

Age

Cal

yr B

P

5410 ±110

1650 ±40

1710 ±40

1240 ±40

1880 AD

Dat

es

FIR

20

PINE

20

DOUGLAS-FIR

20

SEQUOIA20

ALDERTANBARK O

AK

20

OAK

2040

COYOTE BRUSH &

Oth

ers

20

SAGEBRUSH

20

Other Sag

e Scr

ub Tax

a

20406080

GRASS

50100150

SEDGE

20

GOOSEFOOT

FILAREE

50 100150

DOCKPLANTAINEUCALYPTU

S

Glenmire - Trees, Shrubs, Herbs, Wetland

Pond Dry

Page 28: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

Dep

th c

m

0

1000

2000

3000

4000

50006000700080009000

10000

Age

Cal

yr B

P

5410 ±110

1650 ±40

1710 ±40

1240 ±40

1880 AD

Dat

es

FIR

20

PINE

20

DOUGLAS-FIR

20

SEQUOIA20

ALDERTANBARK O

AK

20

OAK

2040

COYOTE BRUSH &

Oth

ers

20

SAGEBRUSH

20

Other Sag

e Scr

ub Tax

a

20406080

GRASS

50100150

SEDGE

20

GOOSEFOOT

FILAREE

50 100150

DOCKPLANTAINEUCALYPTU

S

Glenmire - Trees, Shrubs, Herbs, Wetland

Mixed Conifer and Hardwood Forest

w/ Sage Scrub

Page 29: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

Dep

th c

m

0

1000

2000

3000

4000

50006000700080009000

10000

Age

Cal

yr B

P

5410 ±110

1650 ±40

1710 ±40

1240 ±40

1880 AD

Dat

es

FIR

20

PINE

20

DOUGLAS-FIR

20

SEQUOIA20

ALDERTANBARK O

AK

20

OAK

2040

COYOTE BRUSH &

Oth

ers

20

SAGEBRUSH

20

Other Sag

e Scr

ub Tax

a

20406080

GRASS

50100150

SEDGE

20

GOOSEFOOT

FILAREE

50 100150

DOCKPLANTAINEUCALYPTU

S

Glenmire - Trees, Shrubs, Herbs, Wetland

Historic Period

Page 30: Scott Anderson 2-2-06 - NPS

Creamery Bay Bog• 6 m above sea level• At the head of

Creamery Bay• Site of “K” Ranch

dairy farm• Oldest ranch site on

the Point (Livingston 1994)

• Presently the site is a wet meadow

Page 31: Scott Anderson 2-2-06 - NPS

Creamery Bay Bog

Page 32: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

Dep

th c

m

0

100020003000400050006000700080009000

Age

yr C

al B

P

9010 ± 40

1840 AD

1902 AD1963 AD

Dat

es

20

PINE

DOUGLAS-FIR

SEQUOIAOAKALDERSAGEBRUSH

Other Sag

e Scr

ub Tax

a

204060

COYOTE BRUSH &

Oth

ers

20 40 60

GRASS

20 40 60

SEDGE

50100150200

FERNSWILLOW

20

QUILLWORT

20

DOCK

20

PLANTAIN

20

DANDILION &

Other

s

FILAREECORNEUCALYPTU

SCreamery Bay Bog - Trees, Shrubs, Herbs, Wetland

Grassland w/ ferns, herbs; site dry

Page 33: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

Dep

th c

m

0

100020003000400050006000700080009000

Age

yr C

al B

P

9010 ± 40

1840 AD

1902 AD1963 AD

Dat

es

20

PINE

DOUGLAS-FIR

SEQUOIAOAKALDERSAGEBRUSH

Other Sag

e Scr

ub Tax

a

204060

COYOTE BRUSH &

Oth

ers

20 40 60

GRASS

20 40 60

SEDGE

50100150200

FERNSWILLOW

20

QUILLWORT

20

DOCK

20

PLANTAIN

20

DANDILION &

Other

s

FILAREECORNEUCALYPTU

SCreamery Bay Bog - Trees, Shrubs, Herbs, Wetland

Grassland w/ Sage Scrub; some

Ponding?

Page 34: Scott Anderson 2-2-06 - NPS

0

20

40

60

80

100

120

Dep

th c

m

0

100020003000400050006000700080009000

Age

yr C

al B

P

9010 ± 40

1840 AD

1902 AD1963 AD

Dat

es

20

PINE

DOUGLAS-FIR

SEQUOIAOAKALDERSAGEBRUSH

Other Sag

e Scr

ub Tax

a

204060

COYOTE BRUSH &

Oth

ers

20 40 60

GRASS

20 40 60

SEDGE

50100150200

FERNSWILLOW

20

QUILLWORT

20

DOCK

20

PLANTAIN

20

DANDILION &

Other

s

FILAREECORNEUCALYPTU

SCreamery Bay Bog - Trees, Shrubs, Herbs, Wetland

Historic Period

Page 35: Scott Anderson 2-2-06 - NPS

Wildcat Lake• 62 m above sea level• Sits on a complex

landslide deposit • Coastal scrub • Area NW of lake

(Wildcat Ranch) was occupied as early as 1858 (Livingston 1994)

• Cored in 8.75 m of water

Page 36: Scott Anderson 2-2-06 - NPS

Wildcat Lake

Page 37: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

600

700

800

900

1000

1100

Dep

th c

m

0500

100015002000

2500

3000

Age

Cal

yr B

P

3110 ±60

2000 ±40

1850 AD

Dat

es

20

PINE

20

DOUGLAS-FIR

2040

SEQUOIAOAK

20

SAGEBRUSH

Other Sag

e Scru

b Taxa

20

COYOTE BRUSH &

Others

20 40

GRASSSEDGECATTAIL

20

WATER-MILFOIL

2040 60

ALDER

50100150

SWEET GALE

20

WILLOW

50010001500

PEDIASTRUM

DOCKPLANTAIN

THISTLE

FILAREEEUCALYPTUS

Wildcat Lake - Trees, Shrubs, Herbs, Wetland

Pond Forms; Alder

Page 38: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

600

700

800

900

1000

1100

Dep

th c

m

0500

100015002000

2500

3000

Age

Cal

yr B

P

3110 ±60

2000 ±40

1850 AD

Dat

es

20

PINE

20

DOUGLAS-FIR

2040

SEQUOIAOAK

20

SAGEBRUSH

Other Sag

e Scru

b Taxa

20

COYOTE BRUSH &

Others

20 40

GRASSSEDGECATTAIL

20

WATER-MILFOIL

2040 60

ALDER

50100150

SWEET GALE

20

WILLOW

50010001500

PEDIASTRUM

DOCKPLANTAIN

THISTLE

FILAREEEUCALYPTUS

Wildcat Lake - Trees, Shrubs, Herbs, Wetland

Coastal Sage Scrub w/ minor

Grassland & Mixed Forest

Page 39: Scott Anderson 2-2-06 - NPS

0

100

200

300

400

500

600

700

800

900

1000

1100

Dep

th c

m

0500

100015002000

2500

3000

Age

Cal

yr B

P

3110 ±60

2000 ±40

1850 AD

Dat

es

20

PINE

20

DOUGLAS-FIR

2040

SEQUOIAOAK

20

SAGEBRUSH

Other Sag

e Scru

b Taxa

20

COYOTE BRUSH &

Others

20 40

GRASSSEDGECATTAIL

20

WATER-MILFOIL

2040 60

ALDER

50100150

SWEET GALE

20

WILLOW

50010001500

PEDIASTRUM

DOCKPLANTAIN

THISTLE

FILAREEEUCALYPTUS

Wildcat Lake - Trees, Shrubs, Herbs, Wetland

Historic Period

Page 40: Scott Anderson 2-2-06 - NPS

Shutter Ridge Pond• 35 m above sea level• In California annual

grassland• Situated on a push ridge• Site originally settled by

Garcia family• Probably became part of

Shafter’s “W” Ranch in the 1860’s (Livingston 1994)

• 1 m deep, but dries out

Page 41: Scott Anderson 2-2-06 - NPS

Shutter Ridge Pond

Page 42: Scott Anderson 2-2-06 - NPS

0

10

20

30

Dep

th c

m

0

400800

1200160020002400

Age

Cal

yr B

P

2780 ±40

1840 AD

Dat

es

20

PINE

DOUGLAS-FIR

SEQUOIAOAKALDERSAGEBRUSH

CALIFORNIA-LILAC

20

COYOTE BRUSH &

Others

Coastal S

age Scru

b Taxa

20 40GRASS

20

SEDGE

20 40

QUILLWORTCATTAILDOCK

20

PLANTAINFILAREE

Shutter Ridge Pond - Trees, Shrubs, Herbs, Wetland

Grassland w/ Sage Scrub & Woodland

Page 43: Scott Anderson 2-2-06 - NPS

0

10

20

30

Dep

th c

m

0

400800

1200160020002400

Age

Cal

yr B

P

2780 ±40

1840 AD

Dat

es

20

PINE

DOUGLAS-FIR

SEQUOIAOAKALDERSAGEBRUSH

CALIFORNIA-LILAC

20

COYOTE BRUSH &

Others

Coastal S

age Scru

b Taxa

20 40GRASS

20

SEDGE

20 40

QUILLWORTCATTAILDOCK

20

PLANTAINFILAREE

Shutter Ridge Pond - Trees, Shrubs, Herbs, Wetland

Historic Period

Page 44: Scott Anderson 2-2-06 - NPS

NO POLLEN PRESERVED

Coast Trail Pond

Shutter Ridge Pond

Creamery Bay Bog

Glenmire Wildcat Lake

Sage Scrub w/ Mixed

Conifers & Hardwoods

Sage Scrub w/ Mixed

Hardwoods

Open Hardwood Forest w/

Sage Scrub

Closed Coastal Conifer Forest

Grassland w/ Sage Scrub & Forest

Grassland w/ Sage Scrub

Grassland w/ Ferns,

Herbs

NO POLLEN PRESERVED

Mixed Conifer & Hardwood

Forest

Mxd Conifer – Hdwd, incrSage Scrub

Coastal Sage Scrub w/

Grassland and Minor

Mixed Forest

0

2

4

6

8

10

12

14

Cal Yr BP x 1000

0

2

4

6

8

10

12

14

Cal Yr BP x 1000

Higher Elevation

Lower Elevation

Alder

Historic Period –

Introduced Herbs

(Rumex, Erodium, Plantago) and Trees

(Eucalyptus)

(230 m asl)

(167 m asl)

(62 m asl)

(35 m asl)

(6 m asl)

Moist Dry

Page 45: Scott Anderson 2-2-06 - NPS

Solar Maximum in early Holocene

Kutzbach & Guetter 1986

Page 46: Scott Anderson 2-2-06 - NPS

Changes In SST

Herbert et al (2001)[also Barron et al 2003 & Lyle et al

(2001)]

Page 47: Scott Anderson 2-2-06 - NPS

CA Sea Surface Temp & δ18O

Barron et al. (2003)

Page 48: Scott Anderson 2-2-06 - NPS

Simulated Precipitation

for

Jan & July,

21K, 16K, 14K, 11K, 6K

& Present

Bartlein et al., 1998

Page 49: Scott Anderson 2-2-06 - NPS

Barron et al. (2003)

5000

100001500020000

2500030000

3500040000

4500050000

5500060000

65000

Age

200

300

400

500

600

700

800

900

1000

Dep

th

20 40

CYPRESS Family

100 200 300 400

PINE (a

ll typ

es)

20

DOUGLAS-FIRFIR

20 40 60

SEQUOIA

OAKTANOAKALD

ER

20

COYOTE BRUSH &

Othe

rsLaguna de las Trancas (near Santa Cruz)

Anderson et al, unpublished

Page 50: Scott Anderson 2-2-06 - NPS

Northern Channel Islands & Inland

Empire

Page 51: Scott Anderson 2-2-06 - NPS

Southern California

Sites

Cañadade los

Sauces (SCI)

Soledad Pond (SRI)

Abalone Rocks Marsh

(SRI)

Mystic Lake (RiversideCo)

Dollar Lake

(SBCo)

Page 52: Scott Anderson 2-2-06 - NPS

Santa Rosae Island

Ingram & Kennett 1995

Modern Coastline

Pleistocene Coastline

Page 53: Scott Anderson 2-2-06 - NPS

Cañadade los

Sauces (SCI)

Mystic Lake (RiversideCo)

Dollar Lake

(SBCo.)Soledad Pd (SRI)

Abalone Rx (SRI)

Not Analyzed

Yet

Closed Coastal Conifer Forest

Inland Scrub (Coyote Brush) &

Grassland w/

halophytes

Closed Fir & Pine Forest

NO POLLEN PRESERVED

Coastal Sage

Scrub & Grassland

Coastal Sage Scrub

(More Coyote Brush, fewer Salt Marsh species)

0

2

4

6

8

10

12

14

Cal Yr BP x 1000

0

2

4

6

8

10

12

14

Cal Yr BP x 1000

Maritime Continental

Historic Period –

Introduced Herbs

(Rumex, Erodium, Plantago) and Trees

(Eucalyptus)

(33 m asl)

(275 m asl)

(0 m asl)

(35 m asl)

(2810 m asl)

Moist

Dry

Coastal Sage Scrub(More Salt

Marsh species,

Less Coyote Brush)

Sparse Coastal Sage Scrub

Coastal Sage

Scrub & Grassland

No Permanent

Water; Open

LodgepolePine Forest

Permanent Water

NO POLLEN PRESERVED

Southern California

Inland Scrub (Coyote Brush) & Grassland w/

Woodland Species; Riparian Species

Page 54: Scott Anderson 2-2-06 - NPS

Fire History Studies• Critical to our understanding of the

centennial and millennial-scale fire history is the history of fire over the last two centuries

• Little was known about the pre-Historic fire regimes on the Point Reyes Peninsula until the work of Finney (1990) and Brown et al. (1999)

Page 55: Scott Anderson 2-2-06 - NPS

Fire History Studies

• Brown et al. (1999)– Limatour Road and Five Brooks sites

– periodic fire from the 18th century until ca. 1905 (Five Brooks) or 1918 AD (LimatourRoad)

– Pre-settlement Mean Fire Intervals (MFI) [early 1800’s to ca. 1900 AD ] 7.7 to 8.5 years – characteristic of a surface fire regime

Page 56: Scott Anderson 2-2-06 - NPS

Fire History Studies

• Finney (1990)– Bolinas Ridge and the Kent Lake region

– Pre-settlement MFI 7.5 years for small fires, and < 2 years for larger fires

– Settlement MFI [last half of the 20th century] was an order of magnitude longer

Page 57: Scott Anderson 2-2-06 - NPS

Fire History Studies

• Change in fire regime in 20th century due to cessation of surface fire regime (Finney 1990; Brown et al. 1999) that probably existed during the pre-Historic period.

Page 58: Scott Anderson 2-2-06 - NPS

16000

15500

15000

14500

14000

13500

13000

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Shutter Ridge Pond(35 m asl)

Page 59: Scott Anderson 2-2-06 - NPS

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Wildcat Lake(62 m asl)

Coast Trail Pond(230 m asl)

Shutter Ridge Pond(35 m asl)

General Low Fire during Period of Coastal

Forest – Wet?

Grassland

Open Sage Scrub

Douglas-fir

Page 60: Scott Anderson 2-2-06 - NPS

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Dry Climate –

Sage Scrub or

Grassland

Page 61: Scott Anderson 2-2-06 - NPS

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Wildcat Lake(62 m asl)

Coast Trail Pond(230 m asl)

Shutter Ridge Pond(35 m asl)

Transition Period

Page 62: Scott Anderson 2-2-06 - NPS

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Wildcat Lake(62 m asl)

Coast Trail Pond(230 m asl)

Shutter Ridge Pond(35 m asl)

Consistently Higher Fire Occurrence – Humans ?

Page 63: Scott Anderson 2-2-06 - NPS

Why Synchronous Increase ?• Climate changes → wetter conditions, more biomass

• Human activities– Native American burning ethnographies

– Human habitation of Peninsula by coastal Miwok by 5000 years ago

– 14C dates on archaeological sites on and near Point Reyes increases after ca. 3500 years ago suggesting expanding human population

– These data are not conclusive of Human Burning, but are at least suggestive

Page 64: Scott Anderson 2-2-06 - NPS

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Glenmire(167 m asl)

Wildcat Lake(62 m asl)

Coast Trail Pond(230 m asl)

Shutter Ridge Pond(35 m asl)

Historic Period –General

Decline in Fire

Occurrence (especially at Coast Trail

Pond, Wildcat Lake

& Shutter Ridge Pond)

Page 65: Scott Anderson 2-2-06 - NPS

Summary – General Considerations

• A complex relationship between vegetation, climate, human settlement & fire occurrence– Abundant charcoal produced, but conifer forest and

sage scrub produced more charcoal than did grassland during the Holocene.

– Climate affects the characteristics of each sedimentary basin – determining whether that basin will be perennially wet or periodically dry.

– Local conditions, in turn, affect the local vegetation at each site.

– Human activities can have a potentially large effect on both vegetation and fire history.

Page 66: Scott Anderson 2-2-06 - NPS

Summary – Vegetation Changes• Closed coastal conifer forest until ca. 10,200 yr

ago• Driest Period commenced ca. 10,000 yr ago• Early Holocene established Mixed forest &/or

coastal sage scrub (most locales) and grassland (CBB)

• Still reasonably dry until ca. 6500 yr ago• Modern vegetation established during late

Holocene• Greatest vegetation change is in Historic Period

Page 67: Scott Anderson 2-2-06 - NPS

Summary – Fire Histories• 15k to 10 k – Generally low fire occurrence during period

of coastal forest – Wet?• 10k to 5.5 k - Early Holocene peak in fire activity – dry

climate?• 5.5 to 3.5 k – vegetation change and corresponding fire

history adjustments• 3.5 k to Historic times – general increase in fire, climate

or humans?• Human activities may have had entirely different effects

on the fire regime at different times in the past– Native American populations potentially contributing to high fire

frequencies– Euro-Americans causing fire to become more rare, but perhaps

more destructive

Page 68: Scott Anderson 2-2-06 - NPS

Summary – General Considerations

• Many factors have been important in determining characteristics of vegetation and fire disturbance histories at Point Reyes.

• With increasing human impact on the landscape and our climate, retrospective studies are important

– in understanding how modern vegetation communities came to be as they are today

– as a reference for restoration of former habitats– as a baseline to determine the magnitude of future

impact of humans.

Page 69: Scott Anderson 2-2-06 - NPS

Heartfelt Thanks to: Douglas Hallett (NAU), Mitch Power (Univ Oregon), Dan Buckley (NPS),

Barbara Moritsch (NPS), Jane Rodgers (NPS), Wende Rehlaender (NPS),

Heather Adkins, (NAU), Allison Bair (NAU), Mark Daniels (ERI-NAU),

Kirsten Ironside (NAU), Renata Jass (NAU), Taylor Joyal (NAU), Caitilin

McCracken (NAU), Rob Richardson (NAU), Jaime Toney (NAU), Alison Forrestel

(NPS), Point Reyes GIS Staff