1. Forestry & Society Tropical Forests HORT/RGSC 302 J.G. Mexal Fall 2005

2. Forestry & Society Tropical Forests:Outline Definition Diversity Environmental Factors Forest Gaps Carbon Budgeting Nutrient Cycling Deforestation

3. Forestry & Society Tropical Forests-World Distribution Sharma 1992 Tropical Dry Tropical Deciduous Tropical Rain Temperate Evergreen Temperate Mixed Boreal Temperate Evergreen

4. Forestry & Society Tropical Forests: Definition –Location: 23 o 27’ North (Tropic of Cancer) 23 o 27’ 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 = 27 o C (81 o F) relatively narrow diurnal range = 6-12 o C (11-22 o F) –Soils: highly weathered, nutrient-poor –Photoperiod: 11-13 hr

5. Forestry & Society Species Diversity- butterflies/ Longman & Jenik 1987 Americas Africa/EuropeAsia/Russia 70 60 50 40 30 20 10 20 30 40 50 Species (no.) South North

6. Forestry & Society Species Diversity- Tree Species Canada>55 o NPicea (4 species) Canada>50 o NPinus (9 species) USA25-50 o NPinus (37 species) Mexico15-30 o NPinus (80 species) Brazil10 o S100’s species /ha Tierra del Fuego55 o SNothofagus (3 species)

7. Forestry & Society Tropical Forests-Important Species Longman & 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)

8. Forestry & Society Tropical Forests of Honduras, CA Swietenia humilis caoba Enterolobium cyclocarpum guanacaste Pinus oocarpa ocote Huertea cubensis cedrillo Juglans olanchanus nogal Symphonia globulifera barillo Cordia alliodora laurel Pterocarpus indicus rosewood-rosita Magnolia yoroconte redondo-canelon 44 mm

9. Forestry & Society Tropical Forests Species Rosewood Eucalyptus Madagascar Ebony Koa Paduk

10. Forestry & Society Tropical Forests Species-Chile Prosopis chilensis Algarrobo Donoso Z. 1995

11. Forestry & Society Tropical Forests-Height = F(rainfall)/ Longman & Jenik 1987

12. Forestry & Society Tropical Forests-Canopy Layering/ Longman & Jenik 1987 15 10 5 0 Basal Area Stems (no/ha) Tree Height (m) Amazon forest

13. Forestry & Society Tropical Forests-Height = F(altitude)/ Longman & Jenik 1987 Altitude (m) Height (m) W. Malaysia

14. Forestry & Society Tropical Forests- Forest Gaps/ Longman & Jenik 1987

15. Time after Gap Formation (years) Trees (no/m 2 ) Ghana Species

16. Forestry & Society Tropical Forests- Forest Gaps-Light/ Longman & Jenik 1987 Center of Gap Edge of Gap Inside Forest Cecropia obtusifolia Mexico

17. Forestry & Society Tropical Forests-Canopy Layers-Ps/ Longman & Jenik 1987 Photosynthesis (mgCO 2 /dm 2 /h)

18. Forestry & Society Tropical Forests- Temperate Forests/ Longman & Jenik 1987 Annual Carbon Capture

19. Forestry & Society Forest Productivity Comparison

20. Tropical Forest Biomass/ Dezzo & Chacon ForEcolMgt 2004 5 15 10 Biomass (kg/ha)

21. Forestry & Society Forest Comparisons/ Forestry Hndbk 1984 Biomass & Nutrient Content of Standing Mature Forest

22. C Sequestration via Reforestation/ Restor. Ecol. 2000 Biomass (Mg/ha) Forest Age (yrs)

23. Forestry & Society Tropical Forests- Temperate Forests/ Longman & Jenik 1987 Temperate Coniferous Forest Tropical Rain Forest Organic Matter

24. Forestry & Society Tropical Forests-Temperate Forests/ Longman & Jenik 1987 Carbon Fixation vs Respiration

25. Forestry & Society Tropical Forests- Nutrients Cycling/ Longman & Jenik 1987 Boxes = kg/ha Arrows = kg/ha/yr N = 6.5 K = 7.3 P = 0.5 Ca = 3.6 Mg = 1.3 Dry Wgt = 310,000 kg N = 683 K = 668 P = 37 Ca 1,270 Mg = 187 Dry Wgt = 7,550 kg N = 91 K = 28 P = 5.1 Ca = 95 Mg = 19 N = 30 P = 2.5 K = 71 Ca - 19 Mg = 11 Litter layer Dry Wgt = 6,460 kg N = 91 K = 11.5 P = 4.8 Ca = 96 Mg = 14.5 Soil O M = 515,000 kg N = 19,200 K = 403 P = 2,560 Ca = 3,750 Mg = 682 Roots Dry Wgt = 40,000 kg N = 137 K = 186 P = 6.4 Ca =33 Mg = 61

26. Forestry & Society Forests of the World/ Litter & nutrient residence time (yrs)/ Kozlowski & Pallardy 1999

27. Forestry & Society Tropical Forests- Nutrients (kg/ha)/ Longman & Jenik 1987

28. Kg/ha Nutrient t/ha Venezuela

29. Forestry & Society Tropical 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.

30. Forestry & Society Tropical 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.