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Forestry & Society Tropical Forests. HORT/RGSC 302 J.G. Mexal Fall 2005. Forestry & Society Tropical Forests:Outline. Definition Diversity Environmental Factors Forest Gaps Carbon Budgeting Nutrient Cycling Deforestation. Forestry & Society Tropical Forests-World Distribution. Boreal.
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Forestry & SocietyTropical Forests HORT/RGSC 302 J.G. Mexal Fall 2005
Forestry & SocietyTropical Forests:Outline • Definition • Diversity • Environmental Factors • Forest Gaps • Carbon Budgeting • Nutrient Cycling • Deforestation
Forestry & SocietyTropical Forests-World Distribution Boreal Temperate Mixed Temperate Evergreen Tropical Rain Tropical Dry Tropical Deciduous Temperate Evergreen Sharma 1992
Forestry & SocietyTropical Forests: Definition • Location: 23o27’ North (Tropic of Cancer) 23o27’ South (Tropic of Capricorn) • 40% of land surface = tropics • Precipitation: • Rain Forest: usually exceeds 2,000 mm/yr (79 in/yr) • Dry Forest: 800-1,500 mm/yr (31-60 in/yr) • Temperature: mean annual T = 27oC (81oF) • relatively narrow diurnal range = 6-12 oC (11-22 oF) • Soils: highly weathered, nutrient-poor • Photoperiod: 11-13 hr
Forestry & SocietySpecies Diversity- butterflies/ Longman & Jenik 1987 Africa/Europe Asia/Russia Americas 70 60 North 50 40 30 20 10 10 South 20 30 40 50 Species (no.)
Forestry & SocietySpecies Diversity- Tree Species • Canada >55oN Picea (4 species) • Canada >50oN Pinus (9 species) • USA 25-50oN Pinus (37 species) • Mexico 15-30oN Pinus (80 species) • Brazil 10oS 100’s species /ha • Tierra del Fuego 55oS Nothofagus (3 species)
Forestry & SocietyTropical Forests-Important SpeciesLongman & Jenik 1987 • Mahogany (Swietenia macrophylla) • Teak (Tectona grandis) • Spanish cedar (Cedrela odorata) • Gmelina (Gmelina arborea) • Cacao (Theobroma cacao) • Casuarina (Casuarina equisetefolia) • Ceiba (Ceiba pentandra) • Balsa (Ochroma sp.) • Rubber tree (Hevea brasilensis) • Rosewood (Dalbergia sp)
Forestry & SocietyTropical Forests of Honduras, CA 44 mm Swietenia humilis caoba Enterolobium cyclocarpum guanacaste Pinus oocarpa ocote Symphonia globulifera barillo Huertea cubensis cedrillo Juglans olanchanus nogal Pterocarpus indicus rosewood-rosita Magnolia yoroconte redondo-canelon Cordia alliodora laurel
Forestry & SocietyTropical Forests Species Madagascar Ebony Koa Eucalyptus Rosewood Paduk
Forestry & SocietyTropical Forests Species-Chile Prosopis chilensis Algarrobo Donoso Z. 1995
Forestry & SocietyTropical Forests-Height = F(rainfall)/ Longman & Jenik 1987
Forestry & SocietyTropical Forests-Canopy Layering/ Longman & Jenik 1987 Stems (no/ha) Basal Area Amazon forest 15 10 5 0 Tree Height (m)
Forestry & SocietyTropical Forests-Height = F(altitude)/ Longman & Jenik 1987 Height (m) W. Malaysia Altitude (m)
Forestry & SocietyTropical Forests- Forest Gaps/ Longman & Jenik 1987
Forestry & SocietyTropical Forests- Forest Gaps/ Longman & Jenik 1987 Trees (no/m2) Ghana Species Time after Gap Formation (years)
Forestry & SocietyTropical Forests- Forest Gaps-Light/ Longman & Jenik 1987 Mexico Cecropiaobtusifolia Center of Gap Edge of Gap Inside Forest
Forestry & SocietyTropical Forests-Canopy Layers-Ps/ Longman & Jenik 1987 Photosynthesis (mgCO2/dm2/h)
Forestry & SocietyTropical Forests- Temperate Forests/ Longman & Jenik 1987 Annual Carbon Capture
Biomass (kg/ha) 15 10 5 Tropical Forest Biomass/Dezzo & Chacon ForEcolMgt 2004
Forestry & SocietyForest Comparisons/Forestry Hndbk 1984 Biomass & Nutrient Content of Standing Mature Forest
C Sequestration via Reforestation/ Restor. Ecol. 2000 Biomass (Mg/ha) Forest Age (yrs)
Forestry & SocietyTropical Forests- Temperate Forests/ Longman & Jenik 1987 Organic Matter Temperate Coniferous Forest Tropical Rain Forest
Forestry & SocietyTropical Forests-Temperate Forests/ Longman & Jenik 1987 Carbon Fixation vs Respiration
Forestry & SocietyTropical Forests- Nutrients Cycling/ Longman & Jenik 1987 N = 6.5 K = 7.3 P = 0.5 Ca = 3.6 Mg = 1.3 Boxes = kg/ha Dry Wgt = 310,000 kg N = 683 K = 668 P = 37 Ca 1,270 Mg = 187 N = 30 P = 2.5 K = 71 Ca - 19 Mg = 11 Arrows = kg/ha/yr Dry Wgt = 7,550 kg N = 91 K = 28 P = 5.1 Ca = 95 Mg = 19 Litter layer Dry Wgt = 6,460 kg N = 91 K = 11.5 P = 4.8 Ca = 96 Mg = 14.5 Roots Dry Wgt = 40,000 kg N = 137 K = 186 P = 6.4 Ca =33 Mg = 61 Soil O M = 515,000 kg N = 19,200 K = 403 P = 2,560 Ca = 3,750 Mg = 682
Forestry & SocietyForests of the World/ Litter & nutrient residence time (yrs)/Kozlowski & Pallardy 1999
Forestry & SocietyTropical Forests- Nutrients (kg/ha)/ Longman & Jenik 1987
Forestry & SocietyTropical Forests- Nutrients (kg/ha)/ Longman & Jenik 1987 Kg/ha Venezuela t/ha Nutrient
Forestry & SocietyTropical Forest- -Review Questions • What is a tropical forest? Where does it occur? What is the climate? • What are some of the major species in a tropical forest? • How does species diversity vary with latitude? Give examples. Why does this occur? • What is the ecological significance of a ‘forest gap’? • Describe how environmental factors such as rainfall, elevation, light and temperature affect tree growth and establishment.
Forestry & SocietyTropical Forest- -Review Questions • Describe ‘canopy layering’ in a tropical forest, including the differences in tree number and size with increasing height in the canopy. • Compare and contrast the carbon budgets of a tropical, temperate, and boreal forest. Don’t memorize numbers, just give concepts and relative differences.