Dynamics of natural temperate forests - is there a universal model? Kamil Král & Tomáš Vrška in cooperation with David Janík, Pavel Daněk, Dušan Adam The Silva Tarouca Research Institute, Department of Forest Ecology, Brno, Czech Republic BlueCatresearchteamphoto:KateřinaSlámová 1994 2008 SALAJKA (Beskydy) 1 2 3 4 5 6 7 What we are looking for? To understand the dynamics of tree layer in space and time and the spatial relations. 1994 2008 SALAJKA (Beskydy) 1 2 3 4 5 6 7 What we are looking for? Disturbances - events making growing space available (Picket et White 1985; Oliver et Larson 1990). Disturbances: - frequency - distribution/range - severity/intensity - endo- or exogenous Hypothese: Natural (primeval) temperate forest dynamics is a cyclical process where the different patches with similar development are cyclically changed in the time. The patches have different ratio of living and dead wood and different developmental trends. Questions (no hierarchic order): - which features and variables should we measure? - which scale of assessment should we use (how to assess endogenous and exogenous disturbances)? - how to separate and classify the parts of cycle with similar processes (how to identify the patches of stages in the field/in the datasets)? Three steps:  Definition and classification of stages and phases – 2008-2010  Patch dynamics in the space and varibalitiy of patches on the altitudinal vegetation gradient – 2011-2014  Spatio(multi)-temporal dynamics – transition between stages and phases – 2015-2017 Josef John – first idea how to described the dynamics of temperate forests - 1851 Boubín - longest spatio-temporal dataset in the World Šebková et al. 2011, Forest Ecology and Management Beechwood patch phase Leibundgut, 1959 Zukrigl, 1963 Mueller-Dombois, 1987 ukázky modelů vývojových cyklů temperátních lesů Tabaku et al. 1999 Drössler et al. 2006 0 N d 1,3 0 N d 1,3 0 N d 1,3 Developmental cycle model (Korpel 1978, 1995) timbervolume m3 1000 500 250 0 750 0 200 300 400 years 100 phase of expiration1st cycle 2nd cycle 3rd cycle time Stage of Disintegration Stage of Growth Stage of Optimum Stage of Disintegration phase of regeneration Stage of Growth phase of expiration (Korpel 1978,1995) 0 25 50 m Kuuluvainen 2002 more US studies more EU and JP studies Which scale of assessment should we use? Spatial scales and the often hierarchical nested occurence of different disturbance factors Kuuluvainen 2002 • limits of local and spatial variability • intra- and interspecific competition • single trees trajectory Žofín – stem position map (1975-1997-2008) live recruit dead recruitno record no record no record no record no record no record no record no record no record – stem (still/already) doesn´t exist or doesn´t reach threshold d.b.h. live recruits 2000s 1990s 1970s Žofín: 2008 Žofín: 1997 Žofín: 1975 Different development in the time Method of the moving filter – focal filtering Live trees: Dead trees: d 1,3 [cm] d 1,3 [cm] (21m) Mooving Circle: 0 100 200 300 400 500 600 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 300 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 300 350 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 1-2 3-4 5-6 7-8 9-16 live dead Method of the moving filter – focal filtering Live trees: Dead trees: d 1,3 [cm] d 1,3 [cm] (21m) Mooving Circle: 0 100 200 300 400 500 600 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 300 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 300 350 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 30 60 90 120 150 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 250 1-2 3-4 5-6 7-8 9-16 live dead 0 50 100 150 200 12 34 56 78 910 live dead 0 5 10 15 20 12 34 56 78 910 live dead 0 50 100 150 12 34 56 78 910 live dead 0 2 4 6 8 10 12 34 56 78 910 live dead 0 50 100 150 200 12 34 56 78 910 live dead 0 5 10 15 12 34 56 78 910 live dead 0 20 40 60 80 100 12 34 56 78 910 live dead 0 5 10 15 20 25 12 34 56 78 910 live dead N BA Growth / expiration Growth, initial Growth, advanced Steady State DBH distributions 0 10 20 30 40 50 60 12 34 56 78 910 live dead 0 5 10 15 20 12 34 56 78 910 live dead 0 10 20 30 40 50 60 12 34 56 78 910 live dead 0 5 10 15 20 25 12 34 56 78 910 live dead 0 10 20 30 40 50 12 34 56 78 910 live dead 0 5 10 15 20 12 34 56 78 910 live dead 0 20 40 60 80 100 12 34 56 78 910 live dead 0 5 10 15 20 12 34 56 78 910 live dead N BA Optimum, typical Optimum, ageing Breakdown, initial Breakdown / regeneration DBH distributions Classification using Artificial Neural Network Live trees: Dead trees: d 1,3 [cm] d 1,3 [cm] Stage: Growth Optimum Breakdown Steady State Resulting map of patches - developmental stages and phases Legend: (6%) (16%) (20%) (9%) (14%) (21%) (15%) STAGE Portion of Area Growth 21% Optimum 29% Disintegration 35% Max. stability 15% TOTAL 100% STEADY STATE Steady state Accuracy of Artificial Neural Network classification Král,K., Vrška,T., Hort,L., Adam,D., Šamonil,P., 2010: Developmental phases in a temperate natural spruce-firbeech forest: determination by a supervised classification method. European Journal of Forest Research 129, 339-351. 86 % 91 % Growth / expiration Growth, initial Growth, advanced Optimum, typical Optimum, ageing Breakdown, initial Breakdown / regeneration Steady State Growth Optimum Breakdown Steady State PHASE STAGE 0 N DBH 0 N DBH 0 N DBH Steady state Optimum Growth Breakdown N 0 DBH living trees dead trees 0 N DBH 0 N DBH 0 N DBH Steady state Optimum Growth Breakdown N 0 DBH living trees dead trees Král,K., Vrška,T., Hort,L., Adam,D., Šamonil,P., 2010: Developmental phases in a temperate natural spruce-firbeech forest: determination by a supervised classification method. European Journal of Forest Research 129, 339-351. Three steps:  Definition and classification of stages and phases – 2008-2010  Patch dynamics in the space and varibalitiy of patches on the altitudinal vegetation gradient – 2011-2013  Spatio(multi)-temporal dynamics – transition between stages and phases – 2014-2015 Study Site Census area [ha] Altitude min. [m a.s.l.] Altitude max. [m a.s.l.] Mean annual temp. [°C] Mean annual prec. totals [mm] Years of census Cahnov 17.3 150 153 9.3 517 73’, 94’, 06’ Ranšpurk 22.3 152 155 9.3 517 73’, 94’, 06’ Salajka 19.0 715 815 5.4 1144 74’, 94’, 07’ Žofin 74.5 735 835 4.3 866 75’, 97’, 08’ Boubín 46.7 910 1110 4.0 867 72’, 96’, 10’ 0 50 100 150 20025 m ± Legend: Growth Optimum Breakdown Steady State 1974 1994 2007 Salajka • European beech > 80% • Silver fir and Norway spruce < 10% each • Altitude: 715 - 815 m a.s.l. • Strictly protected since 1937; 19 ha silver fir dieback silver fir dieback 0 100 200 300 40050 m 1975 Legend: Growth Optimum Breakdown Steady State 1997 2008 ± • European beech 65% • Norway spruce 33% and silver fir < 2% • Altitude: 735 - 830 m a.s.l. • Strictly protected since 1838; 72 ha ! 2007 Kyrill Žofín 1972 Legend: Growth Optimum Breakdown Steady State 1996 2010 ± Boubín • European beech 54% • Norway spruce 44% and silver fir < 2% • Altitude: 930 - 1110 m a.s.l. • Strictly protected since 1858 • 45 ha 2008 Emma Stage Proportion [%] 0% 10% 20% 30% 40% 50% 1974 1994 2007 1975 1997 2008 1972 1996 2010 Salajka Žofín Boubín Growth Optimum Breakdown Steady StateMean Patch Size [m] 0 500 1000 1500 2000 2500 3000 1974 1994 2007 1975 1997 2008 1972 1996 2010 Salajka Žofín Boubín Growth Optimum Breakdown Steady State Total • The proportion of stages varies among sites and also in time • Growth stage cover usually 30 – 40 % • Breakdown stage is usually 10-20 % • Steady State seems to increase along altitude (18 -> 38 %) • The MPS is usually higher than average for the Growth stage (in Boubin alternated by SS) • MPS is always subnormal for Breakdown stage • Mean Patch Size is even at the level of the whole mosaic! Patch Analyst 5.1 KRÁL K., McMAHON S.M., JANIK D., ADAM D., VRŠKA T., 2014: Patch mosaic of developmental stages in central European natural forests along vegetation gradient. Forest Ecology and Management 330: 17–28. In contrast to earlier hypotheses, it turns out the patch dynamics has the similar parameters in the N-E US forests: KRÁL K., SHUE J., VRŠKA T., GONZALES-AKRE E.B., PARKER G.G., McSHEA W.J., McMAHON S.M., 2016. Fine-scale patch mosaic of developmental stages in Northeast American secondary temperate forests: the European perspective. European Journal of Forest Research 135 (5): 981-996. Three steps:  Definition and classification of stages and phases – 2008-2010  Patch dynamics in the space and varibalitiy of patches on the altitudinal vegetation gradient – 2011-2013  Spatio(multi)-temporal dynamics – transition between stages and phases – 2014-2015 Christensen et al. 2007 Christensen et al. 2007 0 50 100 150 20025 m ± Legend: Growth Optimum Breakdown Steady State 1974 1994 2007 Multi-temporal comparisons – transitions between stages and phases Rule-based classification of developmental stages and phases - ArcGIS Toolbox - the DBH bins used in different forest types were defined and justified in Král et al. (2014a) - 10 developmental phases described and portrayed by respective local DBH distributions characteristic for individual developmental phases Empiric classification of transitions - all phase-to-phase transitions were quantified between the 70’s and 90’s, 90’s and 00’s and 70’s and 00’s. - descriptive categories: - Stable – the developmental phase remained unchanged between censuses - Progressive – the phase was shifted forward in the cycle - Regressive – the phase was shifted backward in the cycle - Disturbance – a shortcut to early developmental phases likely caused by a disturbance - No trend – development with no clear direction along the forest cycle - Unlikely – unlikely development (a possible misclassification of the phase in either of the observations). Quantitative evaluation of transitions - 10,000 bootstrap samples we derived null distributions for all transition frequencies - for each research plot we used a bootstrap sample size equal to the number of nonoverlapping moving windows necessary to cover the whole area of the plot - we used a sequential Bonferroni-type procedure (Benjamini & Hochberg 1995), which controls for a false discovery rate. example Boubín Green – higher number of transitions than the null model Red – lower number of transitions than the null model The proportion of transitions following preferential, randomly frequent and uncommon pathways Research plots: Boubí n Žofín Salajk a Cahno v - Ranšp urk Mean SEM 90s-00s Period (years) 14 11 13 12 12.5 0.6 Preferential pathways (%) 70.4% 66.1% 70.2% 63.0% 67.4 1.8 Randomly frequent pathways (%) 21.1% 18.8% 27.8% 29.5% 24.3 2.6 Uncommon pathways (%) 8.5% 15.1% 2.0% 7.5% 8.3 2.7 70s-90s Period (years) 24 22 20 21 21.8 0.9 Preferential pathways (%) 76.5% 75.1% 49.6% 57.6% 64.7 6.6 Randomly frequent pathways (%) 13.5% 12.5% 48.4% 37.7% 28.0 9.0 Uncommon pathways (%) 10.0% 12.4% 2.0% 4.6% 7.2 2.4 70s-00s Period (years) 38 33 33 33 34.3 1.3 Preferential pathways (%) 69.7% 61.8% 60.9% 59.7% 63.0 2.3 Randomly frequent pathways (%) 23.0% 28.3% 38.3% 35.5% 31.3 3.5 Uncommon pathways (%) 7.3% 9.8% 0.9% 4.8% 5.7 1.9 The proportion of the three major transition categories in all observations Research plots: Boubín Žofín Salajka Cahnov - Ranšpurk Mean SEM 90s-00s Period (years) 14 11 13 12 12.5 0.6 No transitions (%) 46.6% 45.0% 46.0% 51.7% 47.4 1.5 Cyclic transitions (%) 14.7% 22.0% 27.4% 15.7% 20.0 3.0 Acyclic transitions (%) 38.6% 33.0% 26.5% 32.5% 32.7 2.5 70s-90s Period (years) 24 22 20 21 21.8 0.9 No transitions (%) 30.0% 37.4% 26.2% 34.2% 31.9 2.5 Cyclic transitions (%) 16.7% 23.4% 37.0% 27.8% 26.2 4.3 Acyclic transitions (%) 53.4% 39.2% 36.8% 38.0% 41.8 3.9 70s-00s Period (years) 38 33 33 33 34.3 1.3 No transitions (%) 19.2% 22.5% 20.5% 22.2% 21.1 0.8 Cyclic transitions (%) 20.1% 31.0% 40.8% 34.8% 31.7 4.4 Acyclic transitions (%) 60.8% 46.4% 38.6% 43.0% 47.2 4.8 Three main outputs • in total about 65% of all observed phase-to-phase transitions were significantly more frequent than random switches between phases • about 28% of observed transitions proceeded along pathways of random frequency • only about 7% of observed transitions were realized through pathways significantly less frequent than random switches between phases • the mean ratio of cyclic/acyclic transitions (2:3) was more or less stable throughout time • in average only less than 40% of transitions between different developmental phases were classified as cyclic (following the model cycle), the majority of these transitions were realized through significantly frequent preferential pathways Král K., Daněk P., Janík D., Krůček M. & Vrška T., 2017. How cyclical and predictable are central European temperate forest dynamics in terms of developmental phases? Journal of Vegetation Science – online first Multitemporální analýza % % % % % DĚKUJI OTÁZKY