Principles of dendrochronology
Download
1 / 20

PRINCIPLES OF DENDROCHRONOLOGY - PowerPoint PPT Presentation


  • 206 Views
  • Uploaded on

PRINCIPLES OF DENDROCHRONOLOGY. Set of principles or “scientific rules” Some are specific to dendrochronology Tree selection Others are basic to many disciplines Replication. Crossdating. Matching of ring patterns across trees Widths, density, other features

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'PRINCIPLES OF DENDROCHRONOLOGY' - Albert_Lan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Principles of dendrochronology
PRINCIPLES OF DENDROCHRONOLOGY

  • Set of principles or “scientific rules”

  • Some are specific to dendrochronology

    • Tree selection

  • Others are basic to many disciplines

    • Replication


Crossdating
Crossdating

  • Matching of ring patterns across trees

    • Widths, density, other features

  • Allows year date of formation to be assigned to each ring

  • Critical to dendrochronology


Limiting factors
Limiting Factors

  • Liebig’s Law of the Minimum

    • Rate of a process is limited by most limiting factor

    • Interactions between nutrients

    • Other factors: water?


Limiting factors1
Limiting Factors

  • Tree Growth

    • Cannot proceed faster than is allowed by most limiting factor

    • Degree and duration of a limiting factor change from year to year  ring variation

    • Could be different limiting factors relative to various frequencies of growth


Limiting factors2
Limiting Factors

  • Sheep Mt bcp: moisture/temperature limited at high-frequency

  • Decadal ramp evidence of CO2 limitation?


Aggregate tree growth
Aggregate Tree Growth

  • Ring variation is a function of

    • Age or size

    • Climate

    • Endogenous disturbances

    • Exogenous disturbances

    • Leftover


Aggregate tree growth1
Aggregate Tree Growth

  • To focus on one of these factors, others must be accounted for

    • To study past climate:

    • Sample trees without past disturbance

    • Remove age effect


Aggregate tree growth2
Aggregate Tree Growth

  • Age or size effects removed by detrending


Site and tree selection
Site and Tree Selection

  • Select a site to maximize effect of an environmental factor on tree growth

  • Eliminate or equalize other factors

  • Isolate the single factor of interest

  • Edaphic variationcan be below surface


Site and tree selection1
Site and Tree Selection

  • Not random sampling in true ecological sense

  • Ramifications for inference

    • Instead of saying: Climate affects tree growth in such a way …

    • We might say: Past climate at this site has been such and such …


Replication
Replication

  • Multiple radii to estimate tree growth

  • Multiple trees to crossdate, estimate site patterns

  • Multiple sites to estimate regional tendencies

  • Multiple samplesto establish building sequences


Ecological amplitude
Ecological Amplitude

  • Tree growth more sensitive to environmental factors at edge of species range

  • Altitudinal:

    • Pine sensitive tomoisture at lowerelevational limit


Ecological amplitude1
Ecological Amplitude

  • Latitudinal:

    • Trees may occupy wide variety of microsites in center of range, not limited by single factor

    • Trees may occupy narrow variety of microsites along margins of range


Ecological amplitude2
Ecological Amplitude

  • White oak is classic

    • Enormous range

    • Gentle topography

    • Itrdbfor: “In the East … tree sensitivity to climate increases from the range center out toward the range edge.”


Ecological amplitude3
Ecological Amplitude

  • Might affect age of trees:

    • Schulman, Ferguson 1956 (Science 1954, v. 119, pg. 396, 883)

    • “Young” bcp ineast

    • Old bcp to west

    • Corresponds toaverage rainfalltotals


Ecological amplitude4
Ecological Amplitude

  • Currey 1964:

    • Found oldest bcp on Wheeler Peak, NV

    • “The simple hypothesis of Schulman and Ferguson is … no longer tenable.”


Uniformitarianism
Uniformitarianism

  • Physical and biological processes that link current environmental processes with current patterns of tree growth operated similarly in the past

  • “Present is key to past” (Hutton 1785)


Uniformitarianism1
Uniformitarianism

  • Tree rings from the 1900s calibrated with rainfall records from 1900s

    • Annual precipitation

  • Past rings indicate past precipitation


Uniformitarianism2
Uniformitarianism

  • Have current environmental conditions existed in past?

  • Do past environmental conditions exist currently?

  • Young trees vs. old trees?

    • Szeicz and MacDonald 1994: Age-dependent tree-ring growth responses of subarctic white spruce to climate. CJFR 24:120-132.


Uniformitarianism3
Uniformitarianism

  • Paleo twist: Past is key to future

    • This is why we do what why do


ad