Slide Number 1Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Tree-Rings: The BasicsSlide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35Slide Number 36Slide Number 37Core oldest trees to match a cohort to a fire-scar dateSlide Number 39Slide Number 40Some limitations of the stand-origin fire history methodSlide Number 42Slide Number 43Slide Number 44Some limitations of the stand-origin fire history methodSlide Number 46Methods relevant to assessing historic range of variability and applications in landscape management: D. Egan and E.A. Howell. 2001. The Historical Ecology Handbook: A Restorationist’s Guide to Reference Ecosystems. Island Press.Plan:Quick review of qualitative HRV data sourcesDiscuss quantitative HRV data sources (mostly tree rings)-- readings by Swetnam et al. and Keane et al.Why? Because TR data drive major management initiatives (e.g. FireRegime Condition Classification, LANDFIRE)Geog 4430Short-term historical methodsWritten documentary (textual) sources include:1) early accounts of European explorers (16th-18th centuries); 2) archival documents (both civilian and religious); 3) pre-20th century travelers; 4) Native American sources (e.g. “captivity narratives”; transcriptionsof Native American oral traditions; 19th century ethnologists)5) early scientific and surveying expeditions; and6) local histories.Useful only for major vegetation changes.Discuss: How can the reliability of historical sources be evaluated? How can reporter bias be assessed?George Frederick Ruxton, 1842, writing about the Manitou Springs area:The fire was ignited in the early morning on a spring day when lightning wouldbe an unlikely cause. The fire spread rapidly over a distance of at least fivemiles through “dry pines and cedars” as well as grassland and shrub.“I had from the first no doubt but that the fire was caused by the Indians, whohad probably discovered my animals, but, thinking that a large party of huntersmight be out, had taken advantage of a favourable wind to set fire to the bottom, hoping to secure the horses and mules in the confusion, without therisk of attacking the camp. ...Besides the long sweeping line of the advancingflame, the plateaus on the mountainside, and within the line were burning in every direction, as the squalls and eddies down the gullies drove the fire to allpoints.”Historical maps of vegetationQuality and utility are highly variable.Issues that must be addressed:Spatial scale-- is the map to scale?Positional accuracy-- how can that be assessed?Classification comparability— are the vegetation types comparablein level of detail to modern classifications?Classification accuracy— how can reliability of the historical map be assessed?George Sudworth 1898Battlement Mesa and White River PlateauIn 1898 Sudworth mapped both current cover types, burns in c. 1880s-1890s, and the pre-burn cover typeGeoreference stream confluencesand summits with moderntopographic mapsField check classificationaccuracy:burn boundarieslogic of change or no change (e.g. can’t have400 yr old stand in an 1890 burn; stumps, charcoal, etc.)Terrestrial photographsOnly available after c. 1850.If available, excellent for documenting gross changes and generatinghypotheses to explain the changes (especially when combined withother data).Problems:a. Locations may not be representative (e.g. along roads, railroads)b. Changes are not easily quantifiedc. Both maps and photographs are only “snapshots” in time and maynot be representative of landscape conditions over longer time scales of decades or centuries.Ray Turner and Hal Malde, 1982, southern Front RangeEldoraLilypad (Nymph) LakeAerial photographs/remote sensing imagesExcellent for quantifying changes in cover type. Problems:a. Aerial photographs older than c. 1935 are rare.b. Rarely allow identification of individual species.Re-measurement of General Land Office Surveys--information recorded on tree species and size, burns, forest vs. non-forest vegetationwhen the Range and Township survey grid was established (late 1800s in the Rockies--problems:bias in selecting marker trees?estimated or measured tree sizes?Williams and Baker, 2010, J. Biogeog 37, 707–721Bearing treesBrief Introduction to Dating Fires from Tree Rings*•Fire scar method•Stand-origin (cohort) methodTree-Rings: The Basics• Sources on Tree-Rings– http://www.ltrr.arizona.edu/treerings.html– http://web.utk.edu/~grissino/ltrs/lectures.htmNote the five major portions of the tree trunk.Some Definitions for Understanding Tree-Rings:Cambium: the growing (generative) layer between the xylem and phloem.Xylem: principle strengthening and water conducting tissue of the stem, roots, and branches.Tracheids are elongated cells in the xylem, serving in the transport of water.Phloem: inner bark, principal function to distribute manufactured foodstuffs.Bark: dead, outer tissue that protects the cambium from the externalenvironment and exposure to pathogens and physical injury.Sapwood: outer core of xylem (water conducting)Heartwood: inner core of xylem (usually plugged, often darker)Annual rings are in the xylemBarkEarlywood vs.latewoodThe fire-scar record from tree rings when recorder tree survives wounding.Fire scars on sugar pine, Sequoia National Park, CaliforniaCatface of multiple fire scars on single treeTable Mountain pine log, Reddish Knob, VirginiaThe fire-scar record from tree rings.Fire scars on ponderosa pine, El Malpais National Monument, New MexicoHealed fire scars…missing data?Fire scars on giant sequoia, Sequoia National Park, CaliforniaIntra-ring position of fire-scar tip...dormant season vs. growing seasonFire scar on southwestern white pine, Mt. Graham, ArizonaMean Composite Fire Interval= mean interval between successive fire years in a designated area; CFI can include all fire years within the area or can be “filtered” (e.g.years with at least 2, 3, etc. fire-scars)Some limitations of composite MFI–1) It is highly dependent on size of the search area;2) It does not discriminate between small versus large fires or even between