4.0:SUSTAINABLE USE OF FOREST RESOURCES

     4.1: Types of forest resources

Concepts from this subtopic

a. 
Identify
types of forests

b. 
Locate
the distribution of forests by type

c. 
Explain
factors for distribution of forests

Forest refers to an extensive area of
land which is mostly covered by trees of different sizes and species. Or

A forest is a dense growth of trees, plants
and undergrowth covering a large area of land.

Forest refers to the
collection of trees, which can be natural or planted trees.

Forestry it refers to the
caring/managing, and harvesting of forests and forest resources 

TYPES OF
FORESTS

  
i.  There are two broad
types of forests: Natural forests

  ii.  Planted (artificial)
forests.

Natural forests are the type of forest
that develop naturally without intervention of man

Planted forests are planted and cared
for by man. 

CATEGORIES
OF FORESTS 

Distribution of Forests by Type Due to factors such as
climate and tree species, natural forests can further be subdivided into the
following broad categories.

1.           
Tropical
rainforests:
They are found around the equator, between 23.5°N and 23.5°S. Trees in the
tropical rainforests are tall and often take a very long time to mature. They
consist of indigenous trees which are typically broad-leaved, and they contain
thick under growths of shrubs and other vegetation.

2.           
Temperate
forests:
These forests occur in the mid latitudes of both hemispheres. There are four
distinct seasons in temperate deciduous forests and precipitation falls
throughout the year, as rain in the spring, summer and fall and snow in the
winter. The forest floor in temperate forests supports mosses, ferns and wild
flowers. Maple, oak and birch trees are some examples of the deciduous trees
that dominate these forests. There are also small numbers of evergreen trees
such as pines and fir.

3.           
Coniferous
forests:
Coniferous forests are typically found in coastal areas with mild winters and
heavy rainfall or in inland mountainous areas with mild climates with
temperature that fluctuates little throughout the year. Evergreen conifers
dominate these forests. They are characterized by evergreen, need-leaved trees,
with little undergrowth and tall trees which take very long time to mature.
Dominant tree species found in coniferous forests include cedar, cypress,
Douglas fir, pine, spruce and redwood. Some deciduous trees such as maple, and
mosses and ferns are common in coniferous forests.

4.  Deciduous forests: Deciduous forests are composed mainly of broad-leaved trees that
shed all their leaves during the dry season. Figure 4.5 shows a part of a
deciduous forest. These forests are located between 300 and 500 North and South
of the Equator. They are found in the eastern side of North America, Western
Europe, Northern Coast of China, Japan, Southern and Western Australia

5. Mangrove forests: Mangroves are a collection of salt tolerant trees and shrubs that
grow on estuaries and deltas of tropical and subtropical coastlines. In
Tanzania, mangrove forests cover most of the coast of the Indian Ocean (Dar es
Salaam, Tanga, Mtwara, Pwani and Zanzibar).

 Types of forest resources 

i.        
Timber
for making furniture and constructional works or match making for pit pups and
making of wood pulp for manufacturing new prints and crayon. In Brazil 30% of
timber is used mainly for furniture, harbor piles and clock gates, boat
building and tanning extractions, 70% is used for fuel

ii.        
Raisins
and gum Are obtained from tree balks for example rubber trees 

iii.        
Fiber
materials for different uses such as shifting for upholstery cushions

iv.        
Oil
from nuts Can be processed for vegetable oil for example palm trees 

v.        
Fruits
and flowers for human and animal consumptions peaches trees, mango trees, guava
trees 

vi.        
Medical
plants Including the castor oil plant, salsa parilla, cinchona which are used
for making genuine medicine.

 Factors for Distribution of Forests 

Forest distributions are affected by a number of
factors which include the following:

I.  
Soil:
Different types of soil offer various types of vegetation. For example, a damp
and marshy soil will favour growth of types of trees such as mangroves, which
are generally found on the coastal areas of the tropics or subtropics. On the
other hand, sandy soils located in dry desert areas will support prickly bushes
and cactus where the aim of the plant is to conserve water.

II. Rainfall: Water is an
essential component of all living organisms. Trees need water for various
physiological functions such as photosynthesis and cooling. Hence, it is
essential for growth and development of any particular vegetation. Forests
thrive well in areas that receive sufficient rainfall which is evenly
distributed throughout the year.

III.     
Temperature:
The warm and wet equatorial climate supports the growth of mainly huge, tall,
deciduous trees. The cooler temperate climate supports needle-leaved trees
which are adapted to that particular climate. The moderately hot tropical
climate supports a variety of softwood and hardwood trees which thrive best in
the tropics.

IV.      
Relief:
Relief refers to variation in altitude in an area. Differences in altitude
along the slope of a mountain bring about differences in the type of forests
along a mountain slope. For example, you will always find dense forests on the
foot of Mount Kilimanjaro. As you move up from the foot of the mountain, the
vegetation type and density changes gradually. At a height ranging between 1800
and 2800 m, there is the tropical rainforest, followed by the temperate forest
at around 4000 m. Between 3000m and 3500 m, the forest is dominated by scanty
vegetation, with patches of a bamboo forest.

V. Aspect: In physical
geography, aspect generally refers to the horizontal direction to which a
mountain slope faces. The slope of a mountain facing the direction of
prevailing winds (windward side) will always receive higher amounts of rainfall
than the slope facing the opposite side (leeward side). For this reason, dense
forests will always grow on the windward side, due to abundant rainfall, while
the leeward side will consist of scanty and poor vegetation.

VI.      
Drainage:
If the soil has too much water, plants cannot get enough oxygen from the soil.
This will affect root respiration and the plants may eventually die. On the
other hand, plants cannot grow well if they do not have healthy roots for
absorbing water from the soil. So, the proper balance of plant health, water
and air is necessary for maximum plant growth and development. Well drained
soils support growth of a variety of big trees compared to water-logged and
swampy lowland. However, few plants such as mangrove can thrive in shallow sea
shores which are more or less permanently covered by water.

VII.    
Human
activities: Human activities such as clearing the vegetation to get land for
agriculture or settlement greatly affect the distribution of forests. Most of
the natural forests of the world have been cleared by man. In some parts man
has planted forests (artificial forests) on bare lands or in place of natural
forests.

 4.2: Importance of forestry resources

Concepts from this
subtopic

a. 
Describe
importance and value of forests in social and economic life

b. 
Explain
the importance of forests in ecological and environmental balance

 Importance
and value of forestry resources

Forests are great important in our
life and play a great role to in the ecology and environmental balance as the
following:

   i.      Forests prevent soil
erosion; Trees and grasses preventing movement of agents of erosion like water
winds and moving ice.

 ii.      They maintain water
sources like rivers, catchment areas, springs and lakes. This is due to the
fact that forest support rain formation.

iii.      Forests are also used
for scientific studies (research).

iv.      Where there is a variety
of trees, tourism can develop because of scenic beauty. Hence the country can
gain foreign money.

  v.     
Forests
provide habitats for animals and birds of different varieties.

vi.      Forests contribute to
the modification of the climate especially through rain formation and moisture
conservation.

vii.      Forests also introduce
oxygen in the environment which is produced during photosynthesis. In this
process the trees clean the air by absorbing carbon dioxide. Carbon dioxide is
the raw material used during photosynthesis.

viii.      Trees are also a source
of fuel energy since they are used for firewood and charcoal making.

ix.      Forests also provide raw
materials for paper and pulp industries from which writing materials are
produce They provide building
material like poles and timber.

  x.     
Some
tree species are used for making medicine and also provide fruits as well as
ornamental flowers.

xi.      Forests contribute to
soil development through rotting of leaves which lead to formation of humus.
Humus is very important in improving fertility and facilitate plant growth.

4.3: Important areas of forest products, their
transport and use in the world

concepts
from this subtopic

a.     
Identify
important countries in Timber production

b.     
Explain
the means of transport and problems of timber transportation in the world.

 Important
country in Timber production

Timber
transportation

a.     
Logs
are pulled by cartapillars or by tractor- driven trailers and lorries out of
the dense forest to the saw mills.

b.     
The
sawn timber is then transported to the market. Timber destined for oversea are
transported by water

c.     
Timbers
are floated in water channel of river to the saw mills located nearby rivers.

 4.4: Problems
associated with forestry resources harvesting

Concepts from this
subtopic

a.     
Describe
Problems facing forestry resources harvesting

b.     
Describe
ways do address problems facing forestry resources harvesting

Problems
facing with forestry resources harvesting

Over exploitation of
forest resources (effects of deforestation) can lead to the following
environmental problems;

i) Increase in soil
erosion; As the rain drops /falls harshly in the exposed soil and remove the
fertile soil.

ii) Excessive
evaporation; This causes drought #(problems of water because streams and
springs dry up).

iii)  Destruction of animal
habitat.

iv)  Accelerated
desertification. This caused by prolonged drought of an area since the absence
of forest affect rain formation.

v)  
Pollution
of the atmosphere which can lead to greenhouse effect and global warming for
example when forests are cleared by burning adding carbon dioxide in the
atmosphere.

vi)  Disappearance of some
species of trees (loss of biodiversity).

vii) Unreliable rainfall due
to the excessive evaporation

Ways do
address problems facing forestry resources harvesting

I.              
Planting
trees where other trees have been cut (reforestation) and planting trees where
there never existed any tree before (afforestation). Setting aside some areas
and declaring them as protected areas.

II.            
Educating
people on the importance of conserving the forest and persuading them to fully
participate in all activities involving forest conservation. Also there should
be clear policies giving directions on the proper use of the forest resources.

III.          
There
should be alternative energy resources used instead of depending on the trees.
For example, Solar energy, Geothermal power, bio-gas and HEP

IV.          
There
should be careful land use planning in order to avoid destruction of trees.
Population control should be encouraged in the countries so as to reduce
pressure on the forest resources and the land in general.

V.            
Agricultural
methods should be improved so as to encourage proper land use methods like
shifting cultivation should be discouraged.

VI.          
Destocking
(reducing the number of animals) should be encouraged among the pastoralists,
because having too many animal leads to the destruction of vegetation. 

VII.        
New
and fast growing trees should be introduced. Agro-forestry means the practice
of inter cropping trees and crops in the same farm. Trees can be inter-cropped
with crops like beans, bananas etc.