Impact of private forestland tenure changes in forest cover, stocking and tree species diversity in Amani Nature Reserve, Tanzania

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Impact of private forestland tenure changes in forest cover, stocking and tree species diversity in Amani Nature Reserve, Tanzania

Impact of private forestland tenure changes in forest cover, stocking and tree species diversity in Amani Nature Reserve, Tanzania

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  • 1. Impact of private forestland tenure changes on forest cover, stocking and tree species diversity in Amani Nature Reserve, Tanzania Mathew Mpanda ICRAF EA Region Seminar presentation 26 th April 2011
  • 2. Background
    • Forests and woodlands in Tanzania occupy 37% (353 000 km 2 ) of the land area
    • These ecosystems makes Tanzania as one of the richest and most diverse countries in Africa in terms of both species and habitats
    • These forests and woodlands comprise different vegetation types and serve for mitigation of and adaptation to climate change, for biodiversity conservation , watershed services, fuelwood and other services
  • 3. Background cont…
    • The role of these forests has, however, been undermined by deforestation which is estimated between 150,000 - 412,000 ha per annum
    • Causes of deforestation are mainly human induced disturbances including encroachment, wildfire, illegal mining, pit-sawing, illegal harvesting for building materials and excessive collection of fuelwood and herbal medicines
    • No forest ecosystem in the country has exception in regard to these causes of disturbances
  • 4. Background cont…..
    • In 1970s – 1980s the East Usambara Mtns suffered intense destructions of habitats and species due unsustainable use including excessive mechanized logging
    • By mid 1980’s internal and external outcry on biodiversity loss and destruction of habitats was difficult to ignore
    • This led to launching of AFIMP to see how best to reverse the negative trend to the East Usambara Mtns ecosystems
      • (i) a need for biodiversity preservation by halting conversion of forestlands into other land uses,
      • (ii) enhancement of forest connectivity of isolated forest blocks of East Usambara Mountains
  • 5. Background cont….. Consolidation of existing forests was further translated into enlargement /annexing of private lands and general lands Period Reserve Area enlarged (Ha) Number of Farmers involved Amount paid (TZS) 1993-1994 Kambai 1046 44 26 113 374 Mtai 1234 87 20 711 409 Mlinga 840 88 35 413 930 1994-1995 ANR 1230 658 25 685 970 Nilo 2253 676 111 766 328 Manga 120 96 7 381 782 2002-2006 Derema corridor 790 1128 2 730 326 407 Total 7,843 2,777 2 957 399 200
  • 6. Why this study……..?
    • The enlargement/annexing exercise in ANR had to affect the following private land categories;
      • Land under the Tea Company
      • Land under the Smallholder farmers
      • Land under the Sisal Company
    • This had implications in the resources by;
      • Re-defined ownership of the forestland
      • Re-defined accessibility to forest resources
  • 7. Why this study….?
    • These changes on forestland tenure in ANR had to institutionalize the management aspect to capture the following;
      • Enhance forest resources and other conservation aspects
      • Address livelihood component to the surrounding communities
    • This study attempted to evaluate this tenure changes on forest resources from private to state ownership
  • 8. Narrowing down of Forest resources
    • This study specifically attempted to address the following questions;
      • What is the impact of tenure changes on forest cover in ANR?
      • What is the impact of tenure changes on stocking in ANR?
      • What is the impact of the tenure changes on species diversity in ANR?
  • 9.
    • EU Mountains are found in the north-eastern part of Tanzania
    • Part of the Eastern Arc Mountains (global biodiversity hotspot)
    • ANR forms the largest block of EU Mountains
    • High biodiversity per unit area (both plants and invertebrates)
    • Over 3,450 species of vascular plants recorded
    • Over 1,000 plant species introduced from across the tropics btn 1902 -1930
    • Area of interest for research and biodiversity monitoring for the last 150 yrs
    METHODS: Study site
  • 10. Blue : Forestland converted from Tea company to state, 1065 ha Green : Forestland converted from smallholder farmers to state, 1112 ha Yellow : Forestland converted from Sisal company to state, 173 ha Grey : Six merged forest reserves (tenure unchanged)
  • 11. Methods: Data collection
    • Forest cover assessment
    • Forest cover assessment was done using remote sensing and GIS techniques
    • Landsat TM satellite images of 2000 and 2006 were used.
    • The 2000 image (taken on 22 January 2000) was used to assess forest cover at the end of the private tenure regime
    • The 2006 image (taken on 23 February 2006) was used to depict the situation after six years of state tenure regime
  • 12.
    • Forest Inventory
    • In 1999/2000, a number of permanent sample plots (PSPs) were established in ANR
    • The reserve was first divided into a rectangular 450 x 900 m grid.
    • Then 50 x 20 m PSPs, altogether 180, were systematically laid in the south-east corner of each rectangle
    Methods: Data collection
  • 13.
    • In 2008 a repetitive survey was carried out on 28 PSPs belonging to the blocks that previously were under private tenure i.e. those experienced tenure changes
    • All trees greater or equal to 10 cm were re-identified with respect to location and species by means of a botanist and local people, and re-measurements were taken for diameter at breast height (dbh)
    • Additional, height measurement of three tree per plot was taken
    Methods: Data collection....Forest inventory
  • 14. Methods: Data analyses
    • Forest cover analyses
    • ERDAS Imagine, ArcView GIS 3.2 and ArcGIS Desktop 10 software were used in image data pre-processing and analysis. Image sub-setting was conducted to the images of 2000 and 2006 to obtain areas of interest
    • Forest cover maps for 2000 and 2006 were developed containing the following five classes: dense forest, semi-closed forest, open forest/woodland, bush/grassland and open areas
    • Then post classification change detection was performed in which classified forest cover maps of 2000 and 2006 were compared.
    • The areas extracted from classification results were used assuming linear relationship to make direct computation of percentage total and annual change;
      • Total change (%) = ((Area year x – Area year x + t )/ (Area year x )) x 100%;
      • Annual change (%) = (Area year x – Area year x + t )/ (Area year x x t years ))/ x 100%,
  • 15. Methods: Data analyses….
    • Forest inventory analyses
    • Identical procedures for estimating forest stocking and tree diversity were applied for the year 1999/2000 and 2008 data
    • Number of trees per plot was summarized and transformed into per hectare values (N)
    • The basal area for individual trees were calculated according to dbh, summarised and transformed into per hectare values for the plot (G)
    • Finally, the volume of individual trees was summarized within plots and transformed into per hectare values (V)
    • Shannon-Wiener index was computed within each block and for the 1999/2000 and 2008 data
    • The statistical significance of temporal changes for stocking parameters and Shannon-Wiener index were analysed using two-tailed t-tests
  • 16. RESULTS: Forest cover changes
    • Results of forest cover analyses show positive changes for dense and semi-closed forest in the block previously owned by the tea company
    • For the block previously under smallholder farmers the area with dense forest has decreased while the area of semi-closed forest has increased
    • For the block previously owned by the sisal company the area of both dense and semi-closed forests has decreased
  • 17. RESULTS: Forest cover cont …. Forest block Description Private tenure (2000) State tenure (2006) Total change Total change Annual change Area (ha) (%) Area (ha) (%) (ha) (%) (%) Tea company Dense forest 697 71.8 729 75.1 +32 +5 +0.8 Semi-closed forest 72 7.4 182 18.7 +110 +153 +25.5 Open Forest/Woodland 48 4.9 17 1.8 -31 -65 -10.8 Bushland/Grassland 119 12.3 31 3.2 -88 -74 -12.3 Open area 35 3.6 12 1.2 -23 -66 -11.0 All 971 100.0 971 100.0 - - - Farmland Dense forest 769 69.2 714 64.2 -55 -7 -1.2 Semi-closed forest 133 12.0 183 16.5 +50 +38 +6.3 Open Forest/Woodland 45 4.0 39 3.5 -6 -13 -2.2 Bushland/Grassland 161 14.5 173 15.6 +12 +7 +1.2 Open area 4 0.4 3 0.3 -1 -25 -4.2 All 1112 100.0 1112 100.0 - - - Sisal company Dense Forest 46 26.6 33 19.1 -13 -28 -4.7 Semi-closed Forest 21 12.1 12 6.9 -9 -43 -7.1 Open Forest/Woodland 26 15.0 21 12.1 -5 -19 -3.2 Bushland/Grassland 76 43.9 106 61.3 +30 +39 +6.6 Open area 4 2.3 1 0.6 -3 -75 -12.5 All 173 100.0 173 100.0 - - -
  • 18. RESULTS: Forest cover changes…..
  • 19.  
  • 20. RESULTS: Forest structure
    • Results of the stocking levels and changes between 1999/2000 and 2008 shows an increase in number of stems, basal area and volume per hectare in all blocks except for number of stems per hectare in the block formerly owned by the tea company
    • The changes however, were not statistically significant at 5% level
  • 21. RESULTS: Forest structure…… Forest block Parameters Private tenure (1999/2000) State tenure (2008) Change (% in brackets) P-value Mean SE Mean SE Tea company ( n=18 ) N (no.ha -1 ) 435 37 424 33 -11 (-2.5) 0.4027 G (m 2 h -1 ) 46.0 5.4 46.8 5.2 0.8 (1.7) 0.6369 V (m 3 ha -1 ) 946.5 133.2 965.3 131.2 18.8 (2.0) 0.6826 Farmland ( n=7 ) N (no.ha -1 ) 290 32 310 35 20 (6.9) 0.1453 G (m 2 h -1 ) 28.7 4.9 32.8 4.8 4.1 (14.3) 0.3762 V (m 3 ha -1 ) 563.1 113.9 651.4 103.6 88.3 (15.7) 0.4696 Sisal company ( n=3 ) N (no.ha -1 ) 137 64 163 55 26 (19.0) 0.2697 G (m 2 h -1 ) 11.5 5.9 13.2 6.5 1.7 (14.8) 0.0996 V (m 3 ha -1 ) 209.9 119.9 239.8 132.7 29.9 (14.2) 0.1476
  • 22. RESULTS: Tree species diversity
    • Number of species recorded in 1999/2000 and 2008 (in brackets) were 67 (76), 45 (49) and 24 (27) for the three forest blocks previously owned by the tea company, smallholder farmers and sisal company, respectively.
    • Shannon-Wiener diversity indices in 1999/2000 and 2008 were not significantly different
    Forest block Private tenure (1999/2000) State tenure (2008) Change P-value Tea company (n=18) 3.50 3.49 -0.01 0.3943 Farmland ( n=7 ) 3.36 3.39 +0.03 0.4650 Sisal company ( n=3 ) 2.97 3.07 +0.10 0.2654
  • 23. Main observation and explanation……
    • Positive changes
    • Stable climatic conditions have been reported for the whole of the Eastern Arc mountains over a long period of time i.e. no incidences of extreme weather
    • High growth rates of tree species and colonization of forest gaps by fast growing species
    • Reduced human disturbances and compliance to rules and regulations by adjacent communities
    • Promoted harvesting of tree from nearby Longuza Forest Plantation, harvesting of Eucalyptus sp. woodlots in highland villages i.e. reduced wood demands
  • 24. Main observation and explanation……
    • Negative changes
    • Uncontrolled fire e.g. adjacent farms preparation, hunting inside the reserve
    • Eruption of god rush in 2003
    • Competition between tree species and grasses i.e. ground covered by long grasses that hinders establishment of tree species
    • Illegal extraction of timber and poles
    • Natural ecological processes e.g. death of bigger trees vs climbers, winds vs Maesopsis
  • 25. Illegal gold mining inside ANR
  • 26. Use of fire in farm preparations in the Western and Southern parts of ANR
  • 27. Illegal timber extraction in ANR
  • 28. Pole extraction in ANR
  • 29. Main observation and explanation……
    • Are the changes enough/as expect
    • Short period of time to expect much changes especially in natural forest of this nature
    • Generally conditions of most forests in the Eastern Arc Mountains are relatively better, one should expect very small changes
    • Low number of sample plots and size of the blocks and high variations between plots
  • 30. Main observation and explanation……
      • Spatial differences between blocks
      • Conditions of the forest resources were quite different for the three blocks around the time when tenure changes occurred
      • Other factors may explain the differences among the blocks as location and include human activities (e.g. accessibility and adjacency to villages) as well as natural conditions (e.g. terrain, elevation, vegetation)
  • 31. Conclusion The results for changes in forest conditions from when the tenure changed until 2006/2008 are somewhat ambiguous There are several exceptions and modifications regarding differences between the blocks When considering the three blocks as one entity one may in general maintain that there have been positive changes regarding forest cover as well as forest stocking and tree species diversity Generally one may expect that without state intervention and a change of tenure major parts of the ANR could have accelerated into more clearing as appears in other areas under private ownerships in the East Usambara Mountains
  • 32. Opening up forest patches for crop cultivation in Mbomole village
  • 33. What are the gaps…? Human dimension in terms of livelihood and governance Bradypodion fischeri
  • 34.  
  • 35. Thank you