ESPM 181:ESPM 181:Fire History Labs:Fire History Labs:

Fire-ScarFire-ScarDendrochronologyDendrochronology

27 February & 6 March 200727 February & 6 March 2007Powerpoint versionPowerpoint version

(posted on the ‘readings’ page of the course (posted on the ‘readings’ page of the course website: website: this supersedes previous versionsthis supersedes previous versions))

Rick EverettRick EverettWildland Fire Lab, ESPMWildland Fire Lab, ESPM

UC BerkeleyUC Berkeleyeverett@nature.berkeley.edueverett@nature.berkeley.edu

Importance of Fire HistoryImportance of Fire History Helps us to understand fire regimes Helps us to understand fire regimes

and systems so we can mimic process and systems so we can mimic process and manage in the contemporary and manage in the contemporary environmentenvironment

A “benchmark” - important base of A “benchmark” - important base of information by which we can measure information by which we can measure change change

Remember that a fire history is a tool Remember that a fire history is a tool for making management decisions, for making management decisions, not the solutionnot the solution

Sources of Fire History Information:Sources of Fire History Information: Fire scars Fire scars

The most common technique (more below…)The most common technique (more below…) Age class distributionsAge class distributions

Use stand age data to reconstruct extent of past firesUse stand age data to reconstruct extent of past fires Fit stand age data to a mathematical model & derive fire Fit stand age data to a mathematical model & derive fire

frequency characteristicsfrequency characteristics Paleoecological techniquesPaleoecological techniques

Examining charcoal and other elements in stratified soil Examining charcoal and other elements in stratified soil sediments (e.g. lake cores, alluvium, mudslides, debris flows). sediments (e.g. lake cores, alluvium, mudslides, debris flows).

Pollen analysis,Pollen analysis, Fossil records.Fossil records.

Historic recordsHistoric records Supplement other data. Helps evaluate both natural and cultural Supplement other data. Helps evaluate both natural and cultural

causes of variability in ecosystems. See Swetnam, et al. causes of variability in ecosystems. See Swetnam, et al. Applied Applied Historical Ecology: Using the Past to Manage For the FutureHistorical Ecology: Using the Past to Manage For the Future . . Ecological Applications, 9(4). 1999. pp. 1189-1206. Ecological Applications, 9(4). 1999. pp. 1189-1206.

Ethnographic accountsEthnographic accounts Verbal Histories Verbal Histories

Photographs and Remote Sensing Photographs and Remote Sensing Can be used as a chronosequence for the period of record of the Can be used as a chronosequence for the period of record of the

imagesimages Detailed fire history for Chaparral developed by Minnich using Detailed fire history for Chaparral developed by Minnich using

LANDSAT for No. Baja and So. California.LANDSAT for No. Baja and So. California.

Data TypesData Types Point FrequencyPoint Frequency

How often fire is scarring a single How often fire is scarring a single individual, or a small group of individual, or a small group of geographically limited individuals (<0.1 ha)geographically limited individuals (<0.1 ha)

Area FrequencyArea Frequency Larger groups of samples: Larger groups of samples:

Stand levelStand level CompartmentCompartment LandscapeLandscape

Fire Scars as Fire Scars as Records of Fire Records of Fire HistoryHistory Fire Scars at base of Fire Scars at base of

tree (catface) created tree (catface) created due to cambial injury due to cambial injury and tree response – and tree response – healing overhealing over

Value of Fire Scars: Value of Fire Scars: Using dendrochronological techniques, we can Using dendrochronological techniques, we can

accurately date fire events to their year of accurately date fire events to their year of formation.formation.

Sometimes we can date to the season of formation.Sometimes we can date to the season of formation. Important clues to characteristics of fire regimes – Important clues to characteristics of fire regimes –

fire return intervals, fire return intervals, fire seasonality,fire seasonality, range of ‘historical’ variabilityrange of ‘historical’ variability

Samples over large areas can lend clues to scale of Samples over large areas can lend clues to scale of fire events.fire events.

Dates of fire events for each sample recorded in a Dates of fire events for each sample recorded in a sample fire chronology.sample fire chronology.

Samples compiled into a master fire chronology.Samples compiled into a master fire chronology. Synchrony or asynchrony of fires can be seen in Synchrony or asynchrony of fires can be seen in

master fire chronology.master fire chronology.

Limitations of Fire Scars as a source Limitations of Fire Scars as a source for Fire Historyfor Fire History A conservative historyA conservative history

Captures low to moderate intensity fires. Captures low to moderate intensity fires. High intensity fires trend towards stand High intensity fires trend towards stand

replacement.replacement.

Fire history studies focus on external Fire history studies focus on external visual cues that a record is present:visual cues that a record is present: Cat faces – i.e. visible fire scars. Cat faces – i.e. visible fire scars. Scars, can, and do, completely heal over –Scars, can, and do, completely heal over –

These aren’t seen until processing These aren’t seen until processing Disadvantage = destructive type sampling.Disadvantage = destructive type sampling.

Dendrochronology and Dating Dendrochronology and Dating Fire ScarsFire Scars Dendrochronology definitions:Dendrochronology definitions:

The study of chronological sequences and The study of chronological sequences and patterns of annual growth in rings (Stokes, patterns of annual growth in rings (Stokes, 1968)1968)

The science that uses tree rings dated to The science that uses tree rings dated to their exact year of formation to analyze their exact year of formation to analyze temporal and spatial patterns of processes temporal and spatial patterns of processes in the physical and cultural sciences. in the physical and cultural sciences. (Grissino-Mayer)(Grissino-Mayer)

Selected Principles of Dendrochronology Selected Principles of Dendrochronology (Fritts, 1976)(Fritts, 1976)

SensitivitySensitivity Variability in ring widths caused by limiting Variability in ring widths caused by limiting

environmental factorsenvironmental factors Complacency =Complacency = lack of width variability lack of width variability It is sensitivity in ring series that allow us to It is sensitivity in ring series that allow us to

match patterns between samplesmatch patterns between samples Cross Dating Cross Dating

Matching of ring patterns in one specimen with Matching of ring patterns in one specimen with corresponding patterns in another (Stokes, 1968) corresponding patterns in another (Stokes, 1968)

The procedure of matching ring width variations The procedure of matching ring width variations and other structural characteristics among trees and other structural characteristics among trees that have grown in nearby areas, allowing the that have grown in nearby areas, allowing the identification of the exact year in which each identification of the exact year in which each ring was formed (Argent, 1998)ring was formed (Argent, 1998)

Why not just count rings? Why not just count rings? Tree ring anomalies:Tree ring anomalies:

Missing, locally absent, and micro rings (easily missed Missing, locally absent, and micro rings (easily missed with increment coring)with increment coring)

False rings (often discerned by diffuse ring boundaries)False rings (often discerned by diffuse ring boundaries) Inaccurate bark death date – cut date (less-than-optimal Inaccurate bark death date – cut date (less-than-optimal

field info)field info) Inaccurate pith date (less-than-optimal field info)Inaccurate pith date (less-than-optimal field info)

Cross dating allows us to date samples for which Cross dating allows us to date samples for which we have no known date:we have no known date: Bark Death Date (?)Bark Death Date (?) Cut Date (?)Cut Date (?) Pith Date (?)Pith Date (?) Ring width patterns in remnant wood (from trees that Ring width patterns in remnant wood (from trees that

died long ago) can be dated by matching ring patterns died long ago) can be dated by matching ring patterns with dated samples (chronosequence). with dated samples (chronosequence).

Doing this, you can overlap trees, and extend the record Doing this, you can overlap trees, and extend the record forward or backward in time:forward or backward in time:

In this way we can extend our fire history back much In this way we can extend our fire history back much farther than even the oldest living tree.farther than even the oldest living tree.

Sampling and Sample PreparationSampling and Sample Preparation Slab SectionsSlab Sections

Minimum number of scars visible to obtain Minimum number of scars visible to obtain maximum amount of datamaximum amount of data

Usually try to obtain several samples in close Usually try to obtain several samples in close proximity, and several groups across areaproximity, and several groups across area

Trees at limits of their range or with limiting Trees at limits of their range or with limiting factors provide “sensitive” ring series factors provide “sensitive” ring series

Use of systematic sampling increasingUse of systematic sampling increasing What you cut you must carry out!What you cut you must carry out! Preparation Preparation

Cut to size with band saw, mountCut to size with band saw, mount Sand surface to a polished finishSand surface to a polished finish

Cross Dating ProceduresCross Dating Procedures Methods of Cross Dating (Argent, Methods of Cross Dating (Argent,

1998)1998) Directly from wood - Professional Directly from wood - Professional

expertise, local knowledge, "marker expertise, local knowledge, "marker years"years"

Skeleton plotting - hand made tree ring Skeleton plotting - hand made tree ring "indices" for a sample/time series in "indices" for a sample/time series in which which particularly narrow rings are particularly narrow rings are marked as long linesmarked as long lines. .

Computer aided cross-dating Computer aided cross-dating (Densiometry)- Using ring widths (Densiometry)- Using ring widths scanned into a discretionary program scanned into a discretionary program (like WinDendro).(like WinDendro).

Skeleton Plot Basics:Skeleton Plot Basics: General Procedure:General Procedure:

Mark arbitrary 10 year ring counts on sample Mark arbitrary 10 year ring counts on sample and graph paper – inner ring = year 0. and graph paper – inner ring = year 0.

Use “moving window” to find rings that are Use “moving window” to find rings that are narrow relative to adjacent ringsnarrow relative to adjacent rings

Relatively narrow rings are marked on graph Relatively narrow rings are marked on graph paper – narrow rings get proportionally taller paper – narrow rings get proportionally taller lines.lines.

Match ring patterns between two samplesMatch ring patterns between two samples Account for missing or false ringsAccount for missing or false rings With a known date on one sample, (such as With a known date on one sample, (such as

formation of the last ring) other samples can be formation of the last ring) other samples can be dated. dated.

Create composite of individual sample plotsCreate composite of individual sample plots Compare composite skeleton plot or individual Compare composite skeleton plot or individual

sample plots to established references (tree ring sample plots to established references (tree ring chronologies, climate data, etc.chronologies, climate data, etc.

For a detailed description of skeleton plotting techniques, see:Swetnam, Thomas W., Marna Ares Thompson, and Elaine Kennedy Sutherland. 1985. Spruce Budworm Handbook: Using Dendrochronology to Measure Radial Growth of Defoliated Trees. USDA Forest Service, Agriculture Handbook 639.

Lab targets for today:Lab targets for today:

Independently perform the skeleton Independently perform the skeleton plotting exerciseplotting exercise

SIGN UP FOR A TIMESLOT FOR SIGN UP FOR A TIMESLOT FOR NEXT WEEKS LAB!!!NEXT WEEKS LAB!!! -Sign up sheet will remain on the door -Sign up sheet will remain on the door

at 360 Mulford (0700-1700 daily)at 360 Mulford (0700-1700 daily) Times: 1300-1700 Tuesday and Times: 1300-1700 Tuesday and

Thursday, 06 and 08 March 2007 Thursday, 06 and 08 March 2007 (additional hours depend on demand)(additional hours depend on demand)

ESPM 181 Fire History Lab 2007 Assignment ESPM 181 Fire History Lab 2007 Assignment THIS WEEKS AND NEXT WEEKS LABS WILL BE COMBINED INTO 1 REPORTTHIS WEEKS AND NEXT WEEKS LABS WILL BE COMBINED INTO 1 REPORTTHIS WEEK:THIS WEEK:1) Read through the first 11 portions "Crossdating Tree Rings Using Skeleton Plotting" located at: 1) Read through the first 11 portions "Crossdating Tree Rings Using Skeleton Plotting" located at: http://www.ltrr.arizona.edu/skeletonplot/introcrossdate.htmhttp://www.ltrr.arizona.edu/skeletonplot/introcrossdate.htm

2) The twelfth portion allows you to "Try skeleton plotting for yourself." This interactive web based program will give you some practice 2) The twelfth portion allows you to "Try skeleton plotting for yourself." This interactive web based program will give you some practice skeleton plotting. Your assignment:skeleton plotting. Your assignment:

a. To get the hang of the program, try skeleton plotting several cores with the following settings: a. To get the hang of the program, try skeleton plotting several cores with the following settings: Sensitivity: 1Sensitivity: 1# Rings: 51# Rings: 51No false ringsNo false ringsNo absent ringsNo absent rings

Print out your one of your properly dated cores (turn in with your lab report). Be sure to show the answer and master chronologyPrint out your one of your properly dated cores (turn in with your lab report). Be sure to show the answer and master chronology

b. Now make things a bit more challenging. Date a core with the following settings:b. Now make things a bit more challenging. Date a core with the following settings:Sensitivity: 3Sensitivity: 3# Rings: 71# Rings: 71False rings possibleFalse rings possibleNo absent ringsNo absent rings

Print out your properly dated core (turn in with your lab report). Be sure to show the answer and master chronology.Print out your properly dated core (turn in with your lab report). Be sure to show the answer and master chronology.

c. Step it up again. Date a core using the following settings:c. Step it up again. Date a core using the following settings:Sensitivity: 4Sensitivity: 4# Rings: 101# Rings: 101No false rings.No false rings.Absent rings possible.Absent rings possible.

Print out your properly dated core (turn in with your lab report). Be sure to show the answer and master chronology.Print out your properly dated core (turn in with your lab report). Be sure to show the answer and master chronology.

3) Now get close to the real thing. Choose 3 "Pseudo-bristlecone pine cores" from the handout. Skeleton plot each of these cores on a 3) Now get close to the real thing. Choose 3 "Pseudo-bristlecone pine cores" from the handout. Skeleton plot each of these cores on a strip of graph paper. Once done, use the "Melthusian Walk Bristlecone Pine Master Chronology" to date your cores. This strip of graph paper. Once done, use the "Melthusian Walk Bristlecone Pine Master Chronology" to date your cores. This chronossequence is posted outside of 360 mulford on the bulletin boards, and is available for viewing from 0700 to 1800 weekdays. chronossequence is posted outside of 360 mulford on the bulletin boards, and is available for viewing from 0700 to 1800 weekdays. Once you have dated each core, mark the date of the first and last ring on your graph paper. Turn these in with your lab report. Once you have dated each core, mark the date of the first and last ring on your graph paper. Turn these in with your lab report.

NEXT WEEKNEXT WEEK4) Date an actual tree cross section, complete with fire scars. This and next weeks' exercises should be combined into one lab report, 4) Date an actual tree cross section, complete with fire scars. This and next weeks' exercises should be combined into one lab report,

which will be worth double the normal amount of points. In your writeup, you should consider the following questions from today:which will be worth double the normal amount of points. In your writeup, you should consider the following questions from today:a. Describe the process of skeleton plotting in your "methods" section.a. Describe the process of skeleton plotting in your "methods" section.b. For the discussion section, What did you observe from each of the following exercises: b. For the discussion section, What did you observe from each of the following exercises:

- Web based skeleton plotting- Web based skeleton plotting- Bristlecone pine activity- Bristlecone pine activity- What are possible sources of error in any of these protocols?- What are possible sources of error in any of these protocols?

DUE: 13 March 2007DUE: 13 March 2007