Mäkisara, Kai

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Experiences on redesigning NFI-plot to supportclassification of laser scanning dataKai MäkisaraNatural Resources Institute Finland (Luke)Other people who participated in the work:Erkki Tomppo, Helena Henttonen, Nea Kuusinen, Nina Vainikainen,Matti Katila, Juho Pitkänen, Mikael Strandström, Ville Pietilä, JouniPeräsaari and unnamed field personnel.Luonnonvarakeskus Naturresursinstitutet Natural Resources Institute Finland www.luke.fiTopicsBackground and scopeDifferences in field work between MPI and NFIPractical constraints on co-operationNumber of re-usable plotsField measurements for studiesExperiments with different plot designsTime aspects (updating, change detection)Conclusions2 Kai Mäkisara c©Natural Resources Institute FinlandBackgroundThis presentation is (somewhat) specific to Finland.We have two inventories: National Forest Inventory (NFI), carried outby Luke, and management planning inventory (MPI), carried out byFinnish Forest Centre (SMK).Both do field work each year around Finland.Many people (including the government funding the inventories) ask:Should the inventories (or some parts of them) be combined to, forinstance, save money?3 Kai Mäkisara c©Natural Resources Institute FinlandHistory and current statusmany kind of small scale co-operation in the pastthe Ministry of Agriculture and Forestry (MMM) initiated in 2012 aneffort to investigate possibilities of co-operation between (orcombining) the two inventoriestwo reseach projects funded by MMM, Forest Centre, and Luke(Metla)first project in 2013-2014, investigating possibilities of co-operation,and measuring 2000 field plots in the Ähtäri ALS area of MPIsecond 2014-2015, developing methods for joint use of field plotsNFI12 (2015-2019) is currently using a fixed radius field plot (9meters, trees above 9.5 cm after 5.64 meters, above 4.5 cm below5.64 meters, small relascope trees)up to NFI11 a truncated relascope plot with maximum radius of12.5 m, relascope factor 1.5 or 2.0MPI uses NFI plots as test material in 20154 Kai Mäkisara c©Natural Resources Institute FinlandDifferences in the field workNFIfive year rotation, one fifth of 60 000 plots measured yearlysystematic sampling over whole Finlanda small number of measured trees per plot is neededmany stand level measurementscomputation of results adapted to the systemMPIALS used to produce raster and small segmented areas10 - 15 areas of 100 000 - 200 000 hectares inventoried yeachyear500 - 1000 field plots for each area, sampling optimized to coverall forest types within area, plots entirely within one stand9 m fixed radius plot, all trees above 4.5 cm, separate plot forseedling stagesampling optimized for each area5 Kai Mäkisara c©Natural Resources Institute FinlandConstraints for unificationHuman and organizatorial constaints:all parties must accept the systembased on the current opinions of what is necessarysystem must be implementable in current organizationsNotable differences in requirements:acceptable number of trees within plotsampling designtimeliness6 Kai Mäkisara c©Natural Resources Institute FinlandFinding re-usable plotsNumber of NFI plots in Central Finland within 100 000 hectares is 255(392 ha/plot, including seedling plots and plots covering severalstands).MPI can’t get all plots from NFI. A practical solution for MPI is to use asmany NFI plots as possible and then measure additional plots.The situation would be better if MPI would not need as many plots as itcurrently uses.longer term research topic7 Kai Mäkisara c©Natural Resources Institute FinlandRequirements for the common field plotNFI does not need many trees per plot, the accuracy comes fromthe number of plots (except for Multisource NFI ... maybe)plot not dependent on development classpermanent and temporary plotsmany stand level observationsMPI needs for ALS more accurate plot-wise information,especially in certain kinds of forest (e.g., young forest)currently 9 m fixed radius plot, all trees ≥ 45 mm measured + plotfor the seedling stageis the NFI12 plot sufficient for MPI?8 Kai Mäkisara c©Natural Resources Institute FinlandThe field measurementsMeasurements have been performed on the MPI laser scanning areain Ähtäri, Central Finland.First field work in 2013: 2468 field plots in a systematic grid in 431 000hectares of forestry land.form L, 8 plots in each cluster, distance between plots 250 m,distance between clusters 4.3 km => 231 ha/plotfixed radius 9 meters, all trees ≥ 45 mm measured + threesubplots for small trees1867 plots within forestry land, 1441 forestry land plots entirelywithin single stand, 1150 in NFI development classes 4 - 6 (youngthinning stand, advanced thinning stand, mature stand)Second field work in 2014: 120 16x16 meter plotsgroups of 2 by 2 plots, i.e., 32x32 meter square measuredlocate so that the 16 by 16 meter plots fit the MPI gridlocated using a two-phase GNSS method => small errorall trees above 25 mm diameter measured9 Kai Mäkisara c©Natural Resources Institute FinlandExperiments with 1150 field plots (Erkki Tomppo, NeaKuusinen ja Matti Katila)NFI development classes 4 - 6, plots entirely within one standthe following plot types were computed (radius always 9 meters):fixed radius plot, trees ≥ 45 mm (MPI)fixed radius plot, trees ≥ 75 mm from 5.64 to 9 m, ≥ 45 mm below5.64 m (k75)fixed radius plot, trees ≥ 95 mm from 5.64 to 9 m, ≥ 45 mm below5.64 m (k95)truncated relascope plot, factor 1.0 (q1)truncated relascope plot, factor 1.5 (q1,5)truncated relascope plot, factor 2.0 (q2)in the experiments presented here trees < 45 mm omitted10 Kai Mäkisara c©Natural Resources Institute FinlandTable : Mean number of tally trees in NFI development classes 4 - 6. Numberof plots 1150.Tally treesMPI k75 k95 q1 q1,5 q2Dev. classes 4-6 29.5 24.8 22.5 14.8 11.5 9.2Dev. class 4 38.4 31.0 26.7 13.9 9.4 7.1Dev. class 5 26.9 23.5 21.9 15.8 12.5 9.9Dev. class 6 23.4 19.4 17.8 13.4 11.7 10.211 Kai Mäkisara c©Natural Resources Institute FinlandGood-enough methods for comparison of different plots:improved k-NN (ik-NN) method, feature weights using geneticalgorithm"standard" features from laser returns and aerial photographstotal results but also results from cases where small number ofsmall trees might affect results (young forests)comparison of field plot estimates and results estimated usingALS and aerial photographs12 Kai Mäkisara c©Natural Resources Institute FinlandTable : Field data based forest parameter estimates calculated from the MPI,k75, k95, q1, q1.5 and q2 plots. Number of plots 1150.MeanMPI k75 k95 q1 q1,5 q2Volume m3/ha 154.36 154.30 154.35 154.69 154.65 154.63Pine vol. m3/ha 97.78 97.81 97.77 98.05 98.50 98.56Spruce vol m3/ha 36.54 36.53 36.54 36.25 35.94 35.80Broadl. vol m3/ha 20.04 19.97 20.03 20.38 20.22 20.27Mean diam. cm 18.74 18.76 18.77 18.85 18.94 19.01Mean height dm 153.99 154.10 154.16 154.68 154.96 155.38Basal area m2/ha 19.49 19.48 19.49 19.52 19.53 19.49Nbr of trees/ha 1157.71 1152.35 1153.51 1160.19 1154.67 1144.16Including trees < 45 mm increases, e.g., the total volume of relascopeplots by 2 m3/ha.13 Kai Mäkisara c©Natural Resources Institute FinlandTable : Differences between estimates computed from specific plot type andthe MPI plot. Number of plots 1150.RMSEk75 k95 q1 q1,5 q2Volume m3/ha 1.85 3.55 11.39 18.80 25.64Pine volume m3/ha 0.85 1.88 7.36 13.25 19.85Spruce volume m3/ha 0.98 1.82 5.52 9.10 12.92Broadl. volume m3/ha 1.22 2.36 6.54 9.89 11.94Mean diameter cm 0.27 0.39 0.88 1.16 1.42Mean height dm 1.60 2.33 5.00 6.48 7.90Basal area m2/ha 0.45 0.77 2.03 3.04 3.89Number of trees/ha 157.64 196.56 422.81 541.32 621.2314 Kai Mäkisara c©Natural Resources Institute FinlandTable : RMSE and bias of leave-one-out estimates of forest variables usingALS and aerial photographs. Number of field plots 1150.RMSE/biasMPI k75 k95 q1 q1,5 q2Volume m3/ha 40.09 40.10 40.06 40.28 41.21 41.810.21 0.19 0.22 0.50 0.89 1.36Pine vol. m3/ha 47.29 47.29 47.28 47.33 47.63 47.951.48 1.52 1.48 1.77 2.61 2.90Spruce vol. m3/ha 44.54 44.55 44.55 44.70 44.87 44.95-0.30 -0.31 -0.30 -0.59 -0.92 -0.85Broadl. vol. m3/ha 20.73 20.73 20.76 20.89 21.12 21.44-0.96 -1.01 -0.96 -0.68 -0.80 -0.69Mean diameter cm 2.66 2.66 2.67 2.68 2.70 2.73-0.18 -0.16 -0.15 -0.08 -0.00 0.04Mean height dm 13.09 13.09 13.11 13.20 13.27 13.35-1.23 -1.13 -1.06 -0.56 -0.29 -0.04Basal area m2/ha 4.65 4.65 4.65 4.71 4.86 4.950.15 0.15 0.15 0.18 0.25 0.27Number of trees kpl/ha 479.20 488.69 492.21 517.75 540.36 556.7110.48 8.65 8.97 14.56 13.67 8.1615 Kai Mäkisara c©Natural Resources Institute FinlandTable : Differences between field plot estimates between a plot type and theMPI plot. All plots within one stand with mean diameter ≤ 11 cm. Number ofplots 70.RMSEf Biasfk75 k95 q1,5 k75 k95 q1,5Volume m3/ha 3.39 6.67 17.33 0.72 0.93 2.80Pine vol. m3/ha 2.02 3.81 10.88 0.23 0.13 1.07Spruce vol. m3/ha 1.31 2.05 5.46 0.16 0.17 0.61Broadl. vol. m3/ha 2.37 4.99 13.12 0.32 0.64 1.11Mean diameter cm 0.29 0.35 1.16 -0.03 -0.04 0.19Mean height dm 1.75 2.20 6.90 -0.30 -0.43 0.57Basal area m2/ha 0.87 1.50 3.65 0.18 0.21 0.59Number of trees/ha 290.91 369.00 928.71 64.15 72.13 147.9916 Kai Mäkisara c©Natural Resources Institute FinlandTable : RMSE and bias of estimates, all plots within one stand with meandiameter ≤ 11cm. Number of plots 70.RMSE/biasMPI k75 k95 q1,5Volume m3/ha 15.98 16.04 16.35 18.246.98 7.27 7.02 9.38Pine vol. m3/ha 21.83 21.93 22.00 22.596.40 6.63 6.39 7.52Spruce vol. m3/ha 13.03 13.01 13.09 13.700.51 0.63 0.77 0.69Broadl. vol. m3/ha 11.67 11.56 11.16 12.060.07 0.01 -0.14 1.17Mean diameter cm 2.15 2.14 2.16 2.471.68 1.66 1.66 1.84Mean height dm 12.37 12.32 12.44 14.068.27 8.08 8.08 9.07Basal area m2/ha 2.88 2.88 2.97 3.290.61 0.70 0.64 1.08Number of trees/ha 749.17 746.34 760.36 808.08-306.80 -273.00 -281.37 -191.2717 Kai Mäkisara c©Natural Resources Institute FinlandTotal volume, plots where mean diameter ≤ 11 cm (N=70)0 50 100 150050100150Mitattu tilavuus m3/haEstimoitu tilavuus m3 /haSMKk7518 Kai Mäkisara c©Natural Resources Institute FinlandTotal volume, plots where mean diameter ≤ 11 cm (N=70)0 50 100 150050100150Mitattu tilavuus m3/haEstimoitu tilavuus m3 /haSMKk9519 Kai Mäkisara c©Natural Resources Institute FinlandBasal area, plots where mean diameter ≤ 11 cm (N=70)0 5 10 15 2005101520Mitattu ppa m2/haEstimoitu ppa m2 /haSMKk7520 Kai Mäkisara c©Natural Resources Institute FinlandBasal area, plots where mean diameter ≤ 11 cm (N=70)0 5 10 15 2005101520Mitattu ppa m2/haEstimoitu ppa m2 /haSMKk9521 Kai Mäkisara c©Natural Resources Institute FinlandVolume of pine, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 80010203040Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, kuusi, m3 /haSMKk7522 Kai Mäkisara c©Natural Resources Institute FinlandVolume of pine, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 80010203040Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, kuusi, m3 /haSMKk9523 Kai Mäkisara c©Natural Resources Institute FinlandVolume of broadleaved, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 80020406080Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, lehtipuut, m3 /haSMKk7524 Kai Mäkisara c©Natural Resources Institute FinlandVolume of broadleaved, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 80020406080Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, lehtipuut, m3 /haSMKk9525 Kai Mäkisara c©Natural Resources Institute FinlandVolume of pine, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 8001020304050Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, kuusi, m3 /haSMKk75SMK−maasto26 Kai Mäkisara c©Natural Resources Institute FinlandVolume of pine, plots where mean diameter ≤ 11 cm (N=70)0 20 40 60 80020406080100120Estimoitu tilavuus, mänty, m3/haEstimoitu tilavuus, lehtipuut, m3 /haSMKk75SMK−maasto27 Kai Mäkisara c©Natural Resources Institute FinlandUpdating of the field plot dataTwo tasks:computational updating of the tree measurementsfinding the trees that have disappeared (or grown in)Computational updating is not a problem because the time interval isnot long.28 Kai Mäkisara c©Natural Resources Institute FinlandIdentifying of missing trees (Nina Vainikainen)The task is to find if significant changes have occurred on the plot =>have trees disappeared?The interpretation should be done as early as possible so that a cutfield plot is not used.based on satellite images in Multi-Source NFIbased on aerial photographs before imaging seasonusing ALS data and aerial photographs after imagingThe research concentrated on the last to approaches, using the Ähtäridata and the permanent plots of NFI.What is done if it is suspected that all trees are not present?updating based on the suspicionre-visit the plot, possibly re-measuring treesdon’t use the plot29 Kai Mäkisara c©Natural Resources Institute FinlandSuccessful interpretation, no changes.30 Kai Mäkisara c©Natural Resources Institute FinlandSlightly uncertain case.31 Kai Mäkisara c©Natural Resources Institute FinlandHopeless case?32 Kai Mäkisara c©Natural Resources Institute FinlandConclusionsUse of same field plots in NFI and management inventory istechnically possible.(Overly) simplistic analysis in the Finnish case is that MPI could getone third of the plots from NFI.Details:the field data collection gets more complicatedtoo many trees measured for NFIwho pays and who benefits?It is very difficult to determine the exact savings for Finland.33 Kai Mäkisara c©Natural Resources Institute Finland

Experiences on redesigning NFI-plot to support classification of laser scanning data

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