Long-term monitoring of tropical logged forests

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This presentation examines in detail a network of evergreen forest plots, involving Amazonia, Africa and South East Asia, and what lessons can be drawn from the long-term studies there about sustainable timber management and about the process of long-term monitoring.

This presentation formed part of the CRP6 Sentinel Landscape planning workshop held on 30 September – 1 October 2011 at CIFOR’s headquarters in Bogor, Indonesia. Further information on CRP6 and Sentinel Landscapes can be accessed from http://www.cifor.org/crp6/ and http://www.cifor.org/fileadmin/subsites/crp/CRP6-Sentinel-Landscape-workplan_2011-2014.pdf respectively.

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Long-term monitoring of tropical logged forests

  1. 1. Long-term monitoring of tropical logged forests A network of evergreen forest plots,involving Amazonia, Africa and South East Asia Réalisation G. Cornu Alain Billand, with Sylvie Gourlet-Fleury and Plinio Sist Cirad Research Unit « Tropical forest goods and services » Sentinel Landscapes Bogor 30/09-01/10/11
  2. 2. A network of research sites in natural tropical forests Mopri, Téné, Irobo (Idefor, Ivory Coast)Paracou (Cirad, Tropique du CancerFrench Guiana) Equateur MBaïki (Icra, MEFCP, RCA) ZF2 (Inpa, Brazil) Capricorne Tropique du Oyan (Iraf, Gabon) STREK (Inhutani I, MF, Indonesia) BULUNGAN (Inhutani II, MF, Indonesia N. Fauvet CIRAD-Forêt 1999 Source : Unasylva, FAO Sentinel Landscapes Bogor 30/09-01/10/11
  3. 3. General objectives : Similar protocols : initial untouched forests, controled logging, variable intensities, and untouched control plots Ecology : prediction of changes in structure, floristic composition and genetic diversity Inter-action between ecology and economy : To determine the modalities and intensity of logging compatible with the long-term supply of timber Prediction of changes in biomass: To take account of climate change in logging norms and standards : optimize carbon DD (mitigation), design forest norms adapted to Photo F. Bouchet-Lannat expected CC (adaptation) Sentinel Landscapes Bogor 30/09-01/10/11
  4. 4. Tools  Experimental sites: surveys, databases, GIS, soils, water, light, T°  Genetics, Molecular tools (PCR-RFLP, RAPD, microsatellites …) Number of trees >= 60 cm dbh (/ha) 1,2 SB (observed) 1,0 StoMat(1) StoMat(2) 0,8 0,6 ADN ADN 0,4nucléaire 0,2 chloroplastique 0,0 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 Years  Models and simulation platforms Sentinel Landscapes Angélique and Bogor 30/09-01/10/11 near neighbors
  5. 5. Experimental designs NParacou (1984 -Cirad) Area surveyed annually or every two years: 94 ha (+ 25 ha) : ~ 73 000 trees 3 types of silvicultural treatments Mbaïki (1982 - ICRA, MEFCP, AFD, Cirad)  Area surveyed annually : 40 ha : ~ 23 000 trees  2 types of silvicultural treatments Sentinel Landscapes Bogor 30/09-01/10/11
  6. 6. Experimental designsBULUNGAN (1997-Present)2 Blocks ~100 ha each1 Block with RIL1 block with CNVIn Each Block: 12 plots, 3 control, 1ha eachLogging intensity varying from low(< 6); medium (6-9) and high (9trees/ha)Every tree dbh  20 cm STREK (1989-1997) RKL 1: 6 plots 4 ha each Post-logging silviculture (15 years) RKL4: 12 plots 4 ha each 6 Plots with RIL (2 MDC50cm, 3 MDC 60 cm) Every tree dbh  10 cm Sentinel Landscapes Bogor 30/09-01/10/11
  7. 7. Modelling tools Types of models  Distribution based models (Usher matrices) • Density-dependent: Paracou (Favrichon 1995), Mbaïki, STREK (Favrichon & Young-Cheol, 1998, Sist & al., 2004) • Density-independent: Paracou (Gourlet-Fleury & al., 2004), Mbaïki (in prep.)  Single tree models • Distance dependent: Paracou (Gourlet-Fleury, 1997) • Distance independent (gap): Paracou (Picard, 1999) Softwares  CAPSIS (http://capsis.free.fr), object-oriented environment developed by INRA, hosting various forest dynamics and stand growth and yield models. Hosts Selva, a tree-based distance dependent model developed by Cirad  StoMat, user-friendly software which runs density-independent matrix models Sentinel Landscapes Bogor 30/09-01/10/11
  8. 8. Some results : monitoring logging damages  In Indonesia: do RIL techniques lower the level of damages in the stand? Are results from Bulungan coherent with results from STREK? Felling Damages to trees BULUNGAN 35 Skidding 80 % of original tree population Felling % of tree damaged 30 Skidding 70 25 60 20 50 STREK 15 40 10 30 5 20 10 y = 4,5x + 3,8 0 CNV RIL 0 48.4 % 30.5 % 3 4 5 6 7 8 9 10 11 12 13 35 Canopy opening 30 25 30 % canopy opening 25BULUNGAN 20 15 20 10 15 5 0 10 CNV EFI 5 y = 1,9x - 2,0 0 48.8 % 34.6 % 3 4 5 6 7 8 9 10 11 12 13 In mixed dipterocarp forests, the capacity of RIL to Felling intensity (n/ha) reduce damage to the stand is limited by logging Sentinel Landscapes Bogor 30/09-01/10/11 intensity (N> 8 trees/ha)
  9. 9. Impact of logging on forest dynamics  In Indonesia: how does logging impact the dynamics parameters of stand and group of species? Results from STREK (RKL4) Mortality G1:  80 % (6/ha) Diameter increment 0,8 G2: 70-80 % (8/ha) 0,7 G3: <70% (14/ha) 0,6 4 3,7 cm/year G0 0,5 3,5 0,4mortality %/yr 3 2,5 0,3 2,5 0,2 1,9 1,7 2 1,6 1,6 1,5 0,1 1,5 1,3 0 1 2 4 0,5 35 Years after logging 0 30 2 Years after logging 4 25 Recruitment n/ha/year 20 S1: pioneers, eg Macaranga spp., 15 Anthocephalus chinensis 10 S2: Dipterocarps except Vatica 5 S3: other species 0 Sentinel Landscapes Pioneers Dipt. Others 30/09-01/10/11 Bogor Total Sources: Nguyen-Thé et al. 1998, Sist & Nguyen-thé 2002
  10. 10. Modeling felling cycles In Indonesia: can we give recommendations in order to achieve sustainable timber management? (Simulations with a density dependent matrix model) MEAN STANDING COMMERCIAL VOLUME 200 UNDER A 35 YEAR CYCLE REGIME G1 150 G2 G3 m3/ha 100 50 0 0 35 70 105 140 175 210 245 280 315 350 385 Years Harvested volume at 1rst cycle:  Stationary harvested volume, 3rd cycle:  44 m3/ha (G1, 6 trees/ha)  35 m3/ha (G1)  78 m3/ha (G2, 8 trees/ha)  41 m3/ha (G2  130 m3/ha (G3, 14 trees/ha)  36 m3/ha (G3) Sentinel Landscapes Source: Sist et al. 2003 Bogor 30/09-01/10/11
  11. 11. Modelling long term tree regeneration and dissiminationF. Guyana, Angélique/main commercial specie 1999 2299 (300 yrs) 2599 (600 yrs) 2899 (900 yrs) Landscapes Sentinel Bogor 30/09-01/10/11
  12. 12. Predict sustainability of timber yieldsLobaye (Central African Republic) – Entandrophragma cylindricum (Picard et al.,2008, Gourlet-Fleury et al., unpublished results) 2.0 80 cm dbh (ha ) 1 Tropique du Cancer 1.5 Mbaïki Equateur 1.0 Number of trees 0.5 Tropique du Capricorne 0.0Felling cycle: 30 years 1980 2000 2020 2040 2060 2080 2100Time needed to recover trees ≥ 80 cm dbh: at least 100 years Year N. Fauvet CIRAD-Forêt 1999 Source : Unasylva, FAOHarvested volume at 1rst cycle (/ha): 20 m3Max. 13% of timber volume recovered, low long-term recovery Sentinel Landscapesrates and high uncertainties Bogor 30/09-01/10/11
  13. 13. Monitor impact of logging on tree genetics  In French Guiana: is the present felling regime (all trees  60 cm dbh, every 40 years) sustainable for the first commercial species (Dicorynia guianensis)? (Simulations with a tree-based distance dependent model, Selva) 1,6 14,0 1,4 12,0 1,2 Effectif >= 10 cm dbh Effectif >= 60 cm dbh 10,0 1 8,0 Demographic 0,8 6,0 viewpoint 0,6 4,0 0,4 2,0 0,2 0,0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 45 90 13 18 22 27 31 36 40 45 49 54 58 63 67 72 76 81 85 90 0 45 90 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 13 18 22 27 31 36 40 45 49 54 58 63 67 72 76 81 85 90 Années Années Allelic richness Diversity (H de Nei) 8 0,7 Exploité Non exploité 7 0,65 6 H de NeiGenetic diversity Ao 0,6 5 viewpoint 4 Exploité 0,55 Non exploité 3 0,5 1 5 9 3 7 1 5 9 3 7 27 1 5 9 3 7 1 5 9 3 7 11 19 27 36 44 53 61 69 78 86 27 11 19 27 36 44 53 61 69 78 86 Années Années Sentinel Landscapes Source: Gourlet-Fleury et al. 2005 Bogor 30/09-01/10/11
  14. 14. Balance logging intensity v/s logging cycle  In Indonesia: what would be the shortest sustainable felling cycle for a given logging intensity? 200 180 tsust = 10,2 e0,162*LIrotation length (years) 160 140  Shortest felling cycle and 120 corresponding mean annual 100 80 volume: 60  27 years, 1.6 m3/ha (G1) 40  41 years, 1.8 m3/ha (G2) 20  89 years, 1.4 m3/ha (G3) 0 2 3 4 5 6 7 8 9 10 11 12 13 14 Logging intensity n/ha On a mean basis, a logging intensity of 8 stems/ha would yield 67m3/ha every 42 years = 1,6 m3/ha/an and should be recommended Sentinel Landscapes Source: Sist et al. 2003 Bogor 30/09-01/10/11
  15. 15. Recovery of trees/species after logging  In French Guiana: how does the commercial timber stock of species recover after logging? Can silvicultural treatments fasten the recovery? How will the floristic composition evolve? Diameter increment 0,5 Espèces principales (58 EGE) 0,45 0,4 0,35DD (cm/an) 0,3 ∆D0 ∆D1 0,25 ∆D2 0,2 ∆D3 0,15 0,1 0,05 0 50 45 1984/1986 1989/1991 1991/1993 1993/1995 1995/1997 1997/1999 1999/2001 2001/2003 40 Effectif recruté (/ha) Périodes 35 30 25 20 15 10 5Recruitment 0 84 4 85 5 86 6 87 7 88 8 89 9 90 0 91 1 92 2 93 3 94 4 95 5 96 6 97 7 98 8 99 9 00 0 01 1 2 8 /8 /8 /8 /8 /8 /9 /9 /9 /9 /9 /9 /9 /9 /9 /9 /0 /0 /0 19 Années T0 T1 T2 T3 Stock recovery Sentinel Landscapes Source: Gourlet-Fleury et al. 2004 Bogor 30/09-01/10/11
  16. 16. Recovery of forests stands Entandrophragma cylindricum (Mbaïki) - Logging intensity 90%  In Republic of Central Africa 1,80 Number of trees >= 80 cm dbh (/ha) 1,60 (simulations with a density 1,40 1,20 Logged (observed) Mean (predicted) independent matrix model, StoMat) 1,00 0,80 0,60 0,40 0,20 40,0 0,00 Sapelli Mbaïki (>= 10 cm)Surface terrière >= 10 cm dbh 7,0 35,0 11 13 15 17 19 21 23 25 27 29 1 33 35 37 39 1 3 5 7 9 84 Effectif total >= 10 cm dbh (/ha) 3 19 6,0 Entandrophragma cylindricum ( Mbaïki). LoggingYear intensity 30,0 90% 5,0 1,8 25,0 4,0 (m2/ha) 1,6 Number of trees >= 80 cm dbh 20,0 1,4 3,0 1,2 2,0 15,0 1,0 (/ha) 1,0 Témoins 0,8 10,0 Exploitées 0,6 0,0 0 2 4 6 8 10 12 5,0 Exp./éclaircies 0,4 Nombre de cycles (30 ans) 0,2 0,0 0,0 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 0 2 4 6 8 10 12 Années Number of felling cycles (30 years)  The number of exploitable trees (4 trees/ha, 66 m3/ha) cannot be recovered within 40 years (around 75% could, less than 70% within 30 years). Thinning the stands should allow it  A serious problem will occur with Entandrophragma cylindricum (Sapelli) and Triplochiton scleroxylon (Ayous). Resp. 15% and 42% recovered within 30 years Sentinel Landscapes Bogor 30/09-01/10/11
  17. 17. The role of large trees  Large trees play a major part in stocks loss, but also recovery Example in Para (Brazil, Cikel Verde) Trees ≥ 60 cm dbh = 30% of standing volumeMazzei de Freitas et al. (2010) Sentinel Landscapes Bogor 30/09-01/10/11
  18. 18. Recovery of carbon stocks Carbon stocks recover, but dynamics similar to commercial stocks => felling cycles too short Paracou (French Guiana) 12 years 50 years Blanc et al. (2009) Sentinel Landscapes Bogor 30/09-01/10/11
  19. 19. New/Recent initiatives in Central AfricaCoforchange (5y, mid Dynafor (just starting) term):  A range of new large scale 4000 y forest/climate history plots (2 x 400 ha) 4.5 million ha of forest  Sampling diversity of Congo inventories /300 sp Basin forests Edaphic conditions (soil,  Involvement of logging water, temperature, etc.) companies Improve logging norms  Design small scale research activities in concessions Sentinel Landscapes Bogor 30/09-01/10/11
  20. 20. Some results : support to decision-making, design of tools , laws, norms New logging practices, better adapted to forest ecology : Number of exploitable trees, Duration of felling Cycle (cf Fr Guyana 30- >60 y) Measure impact of reduced impact logging Promote sylviculture/ Thinning (shortening of felling cycles by 10 to 20y) Maintenance/protection of genetic pools Special attention on selected logged species (fragile, endanged, rare, endemic, etc.) Compensation through REDD+ ? Sentinel Landscapes Bogor 30/09-01/10/11
  21. 21. Scale of plots PSP are essential:  We need some « heavy » PSP to benefit from long- term data series and quantify trends  We also need many lighter PSP in order to quantify the variability of the dynamics parameters and to adapt models to local conditions  A need to undertake a detailed compared analysis of results issued from existing PSP: this could help identify general trends in the reaction of populations and stands to the disturbances linked to logging Better use of simple or complex models to make predictions Photo J.-G. Jourg Complex and detailed models remain essential to explore long-term scenarios and identify critical thresholds Sentinel Landscapes Bogor 30/09-01/10/11
  22. 22. Feasibility Choice of sites: decisive, needs careful, long sampling based on state of the art data Partnerships : (i) South : research with and by national researchers + training from Bsc to PHd (ii) North :networking, merging/optimising costs. Public/private sectors, administrations, NGOs, communities… Funding and permanence issues : the constant nightmare. Juggling with tiny bits. Diverting permanent funds… Financial capacities : Developing v/s emerging countries No research question with single sci. disciplin (ecology, etc.) Always mix questions : ecology and economy, ecology and sociology, etc. Sentinel Landscapes Bogor 30/09-01/10/11

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