Changes in fire regime, forest structure, and tree spatial patterns in ponderosa pine forests of the northern Colorado Front Range, 1860 to 2012

Peter M. Brown 1,4

Chad Julian 2

Laurie Huckaby 3

Paula Fornwalt 3

Michael Battaglia 3

Antony S. Cheng 4

1 Rocky Mountain Tree-Ring Research, Ft. Collins CO2 Boulder County Parks and Open Space, Boulder CO3 Rocky Mountain Research Station, Ft. Collins CO 4 Colorado Forest Restoration Institute, Ft. Collins CO

Buffalo Creek (1996)Hi Meadow (2000)

Hayman (2002)

Black Tiger (1989)

Bobcat Gulch (2000)

Big Elk (2002)

Overland (2003)Four Mile (2010)

High Park (2012)Picnic Rock (2004)

Front Range Forest Reconstruction Network*

2012 Field Season:13 Landscape Units73 0.5 ha plots (3 to 7 plots in each unit)

Funded by:Colorado Forest Restoration InstituteArapahoe-Roosevelt National ForestPike-San Isabel National ForestRocky Mountain Research StationBoulder County Parks and Open SpaceRocky Mountain Tree-Ring Research

FRFRNet Methods:1. Stem map pre-settlement trees within 0.5 ha plots; -2. Subsample age structure and post-settlement structure in 4 500 m2 subplots; 3. Collect all fire-scar evidence in plot and surrounding area.

Lyons

Boulder County Parks and Open Space Hall Ranch

Site MFI (Std dev)11 MeFI22 WMPI33 WMode44 Range

Hall Ranch 14 (9) 12 12 9 3 to 36

Heil Valley Ranch 9 (6) 7 8 6 3 to 23

Combined either 8 (6) 4 7 4 2 to 20

1 Mean fire interval2 Median fire interval 3 Weibull distribution median probability interval (Grissino-Mayer 2001)4 Weibull distribution modal interval

http://photosynth.net/view.aspx?cid=b5b79dde-55e2-4d01-9d3e-2ae09cd74a6f

HA01 HA05 HA16 HA17 HA18 HA24 HE06 HE13 HE180

20

40

60

80

100

120

140Tr

ees

ac-1

Current Historical

Red line = DBH

Terrestrial LIDAR scan profile forHeil Ranch plot 13

Data from Jason M. StokerUSGS Earth Resources Observation and Science (EROS)

Measured DBH to TLS estimated DBH: HE13

A B C D E F0

20

40

60

A

B

C

D

E

F

Current Conditions

Fuels Treatment

Restoration

A B C D E F0

20406080

A B C D E F0

20

40

60

For more information: Peter Brown, pmb@rmtrr.org

DBH

(cm

)

DBH

(cm

)

“Old”

“Transitional”

“Young”

“Pre-settlement” (ca 1880) living trees, defined as ≥ 25 cm dbh OR by morphology

“Post-settlement” living trees, defined as < 25 cm dbh OR by morphology

Pre- Post-