Forest Surveys: Comparing Efficiency and Accuracy of ... › files › 2016_McGarigal_CTS... ·...

ForestSurveys:ComparingEfficiencyandAccuracyofDigitalPhotographyandLaserBasedTechniques

Introduction

Methods

Results Conclusion

FutureResearch

AlisonMcGarigal1,ChuckCannon2

Acknowledgements:WewouldliketothankTheCenterforTreeScienceatTheMortonArboretumforfundingthisresearch.WewouldalsoliketogiveaspecialthanksLaneScher,DrewDuckett,MeghanMidgley,Quin Taylor,ChristineCarrier,JessicaTurner-Scoff,CatherineBechtoldt fortheirhelpandsupport.

1AlisonMcGarigalColoradoCollege,CenterforTreeScienceUndergraduateResearchFellowali.mcgarigal@coloradocollege.edu

Tounderstandhowhumanactivitydrivesshiftsinthecompositionandstructureofforests,wemustdocumentourcurrentforestsasmuchaspossible.• Thetraditionalmethodofcollectingthisdataiscostlyintermsof

humaneffortandtimerequirements• Implementingtechnologycouldallowustoconductforest

surveysoveralargeareamorefrequently

Aim:Todetermineifdigitalphotographyorhand-heldlasertechnologycouldimprovetheefficiencyofforestsurveyingwhilemaintainingtheaccuracyofthetraditionalmethod.

Surveystudydesign• 30circularplotsassignedanareaof314m2,707m2,or1257m2

Techniquestested• Traditionaltapemeasuremethod• Dual-lasermethod• Photographymethod(PhotoPoint)developedbyAusPlots

RangelandsattheUniversityofAdelaide,Australia

Sources:LaBau,VernonJ.,JamesT.Bones,NealP.Kingsley,H.Gyde Lund,andW.BradSmith."AHistoryoftheForestSurveyintheUnitedStates:1830–2004.”(n.d.):n.pag.USDA.USDAForestService,June2007.Web.2Aug.2016.Thompson, I.,B.Mackly,S.McNulty,andA.Mosseler."ForestResilience,Biodiversity,andClimateChange."SecretariatoftheConventiononBiologicalDiversity,Montreal (2013):91-104.ConventiononBiologicalDiversity.ConventiononBiologicalDiversity,2009.Web.2Aug.2016.Dick,AdamR.,JohnA.Kershaw,Jr.,andDavidA.MacLean."SpatialTreeMappingUsingPhotography."NorthernJournalofApplied Forestry27.2(2010):68-74.Web.22June2016.

LaserMethodPhotoPointMethodTraditionalMethod

Figure1.Thetimeittakestocompleteeachmethod Figure2.TheimpactofdistanceontheLaser’sDBHerror

Figure3.ThesignificanceofDBHofthetreesmissed Figure4.Thesignificanceofthedistanceoftreesmissed

Efficiency• PhotoPointisthefastestmethodtested(Figure1;p<0.05)• Whenfewtreesaremeasuredinsmallareas,allmethodsare

similarlyefficient(Figure1;p=0.16)• Nosignificantdifferencebetweenthetimerequirementsfor

TraditionalandLasermethods(Figure1;p=0.799)

Accuracy• ErrorinDBHanddistanceestimationsoftheLaserincreases

graduallyasthedistancetothetreeincreases(Figure2;p<0.05)

m2m2m2 m2 m2 m2

MissedTrees• Lasermethodmissestreesthathavesmalldiameters (Figure3;p<

0.05)andthatareneartheedgeofplots(Figure4;p<0.05)• Traditionalmethodalsomissestreesontheedgeofplots(Figure4;

p<0.05)butoveralargerrangeofdiameters(Figure3)

2Dr.ChuckCannonCenterforTreeScienceatTheMortonArboretumccannon@mortonarb.org

PhotoPoint:goodalternativemethodforconductingforestsurveys• Timerequiredtophotographaplotisindependentofthe

numberoftreesinaplot,whichincreasesit’sefficiency• Potentialforphotographstocollectincidentaldata,suchas

understorythicknessandcomposition,andtreegrowthforms

Lasermethod:pooralternativeforconductingforestsurveys• ComparedtoTraditionalmethod:equallyefficient,lessaccurate

DBHestimates,treesmissedmorefrequently,moreexpensive

• SynthesizedatacollectedbythePhotoPointmethodandcomparetheaccuracyofthedatatotheothertwomethods

• OptimizeprotocolofPhotoPointmethodtogatherthehighestqualityandquantityofdata

• EvaluatethepotentialinsightstheincidentaldatacollectedbythePhotoPointmethodcouldprovide

Area of Plot Area of Plot