Lecture 12
Tropical Forestry

Tropical forestry involves to the exploitation and management of tropical forests.

At the present time tropical forests represent a tremendous reservoir of fixed carbon and an important natural oxygen generating system.

Furthermore tropical rainforests consist of great biodiversity with potential riches for agriculture, horticulture, forestry, and medicine.

Loss of the tropical forest is now considered one of the great potential calamities facing our planet.

The tropical world is not particularly interested in saving the tropical forest for the benefit of the temperate world which has destroyed its forests (at least not without compensation).

 fig. 1

Eucalyptus in Brazil

However the loss of temperate forests is not universal.

In the Eastern United States there is a tremendous regrowth of the native forest.

Driving US 80 across Pennsylvania one sees continuous forest regrowth.

Clearly a way must be found to protect the rainforest and improve the lives of people who live in the tropics.

Leaving all of the tropical forests as a natural reserve for humanity is not an option at the present time because of expanding population in the tropical world.

 fig. 2

Firewood collection: A necessary activity in the tropics

Agriculture may be the "enemy of the forest."

Forests are threatened by

  • Human activity (clearing, burning)
  • Insects (leaf cutting ants, termites)
  • Diseases and parasites

    		•  fig. 3

    Cerrado Burning, Brazil

    fig. 4

    After Burning

    		 fig. 5

    Cerrado - Termites

    fig. 6

    Termite nest, Belize

    		 fig. 7

    Cerrado - Insect Damage

    Tropical Forest Management

    Tropical forest management is complicated and little understood.

    Over 5000 species, and very mixed, often 100–200 species per acre.

    The abundance of many species makes natural extraction of timber species uneconomic.

    For example, Philippine mahogany, grown in Asia is not a single species but many species of the Dipterocarpaceae.

    (True mahogany with very large leaves is Swietenia macrophylla, Meliaceae; Khaya spp. are known as African mahogany).

    Furthermore many important tropical species such as rosewood (Dalbergia nigra, Fabaceae or Leguminosae) do not grow well under management.

    Many tropical legumes, palms, and tropical fruits still await exploitation. The tropical rainforest is also rich in animal and bird biodiversity that are also being threatened.

    Many exotics are being planted, particularly:

  • Pines, tropical species (Mexico, tropical Caribbean)
  • Eucalyptus (Eucalyptus citriodoras Myrtaceae, an import from Australia, will grow twice the rate of pine)
  • Teak (Tectonia grandes, Verbenaceae, native to Burma)

    		•  fig. 8

    Teak

    Many integrated industries associated with forestry

  • Extractive industries (nuts, oil crops, medicinal plants)
  • Pulp mill (disastrous experience of Daniel Ludwig in Brazil along the Jari river)
  • Saw mills
  • Charcoal (important in tropical America because coal is scarce and carbon is need to make steel

    		•  fig. 9

    Teak & Cacao

    fig. 10

    Charcoal, Brazil

    		 fig. 11

    Charcoal, Brazil

    fig. 12

    Forests & Forest Destruction in Brazil

    		 fig. 13

    Deforested highlands, Brazil

    fig. 14

    Erosion Due to Deforestation

    		 fig. 15

    Small Sawmill, Brazil

    fig. 16

    Ponte Nova, Brazil

    		 fig. 17

    Sawmill, Brazil

    fig. 18

    Ponte Nova, Sawmill

    		 fig. 19

    Wood pulp, Brazil

    fig. 20

    Cellulose Fiber Plant, Brazil

    		 fig. 21

    Wood preservation plant

    fig. 22

    Eucalyptus

    		 fig. 23

    Eucalyptus, Brazil

    fig. 24

    Sprouts 1½ years after clear cut

    		 fig. 25

    Eucalyptus, 1½ years, stump resprouting

    fig. 26

    Second growth, Brazil

    		 fig. 57

    Eucalyptus in Portugal

    fig. 27

    Eucalyptus Nursery

    		 fig. 28

    Eucalyptus

    fig. 29

    Eucalyptus

    		 fig. 30

    Eucalyptus

    fig. 31

    Tree planting, Brazil

    		 fig. 32
    fig. 33

    Tree planting, Eucalyptus

    		 fig. 34

    Eucalyptus, 3 months

    fig. 35

    Cerrado, Brazil

    		 fig. 36

    Pine

    fig. 37

    Pinus, Brazil

    		 fig. 38

    Parana Pine

    fig. 39

    Parana Pine

    		 fig. 40

    Pine plantation, Brazil

    Agroforestry: A Silvicultural System

    The name given in the late l970s to a set of ancient techniques that in its broadest sense includes any mixing of trees and crops (or livestock) in the same field appears to be correct approach to manage tropical forests.

    At the present time agroforestry is defined as a system that involves a deliberate mixing of agricultural crops and/or animals with woody perennials.

    The system must produce two or more products on a multiyear cycle.

    The system is more complex ecologically and economically than a monocrop system.

    A significant beneficial interaction is claimed between inputs.

  • Agro-silvicultural: mixture of woody perennials plus traditional agricultural crops
  • Silvo-pastoral: woody perennials plus animals
  • Agro-silvo-pastoral: Combination of woody perennials, crops, and animals.

    • fig. 41

    Forests and Grazing

    		 fig. 42
    fig. 43 fig. 44
    fig. 45 fig. 46
    fig. 47

    Intercroping

    		 fig. 48
    fig. 49

    Multi-cropping in Tropical Rainforest

    		 fig. 52

    Multi-cropping in India

    fig. 50 fig. 51
    fig. 53

    India

    		 fig. 54

    India

    fig. 55

    India

    		 fig. 56

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