BRE 211: Principles of Agriculture and Forestry

LECTURE 9FORESTRY

Introduction World is faced with the problem of managing

the forest environment in a complex social, economic and political setting.

In the past human triumph over the environment was dependent upon the ability to find food, a means of protection from other animals and find shelter from other elements of the environment.

The benefits of forests and tree resources cannot be over emphasised.

Introduction

With the rapid human population growth the quest for greater productivity has intensified the exploitation of the limited forest resources.

This has consequently entailed the encroachment into forestlands and the subsequent pushing of forest resource out of humid zone to marginal areas.

Meaning of Forestry Is the business of managing forestlands and

the forest resources to produce economically useful goods and services.

The trees and other vegetation as well as the soil, which supports them, are important bases for forest management.

The nature of the forest is diverse depending on the soil and climatic conditions prevailing over a specific region of the world.

Meaning of Forestry

Involves several disciplines in the biological and social sciences such as Chemistry Biology Physics Mathematics Economics Sociology political science and law

Meaning of ForestryThe physical and biological sciences

constitute the foundation on which forestry must be laid, whereas application of forestry principles is limited by the socio-economic phenomena.

Forestry production depends increasingly on the availability of resource inputs such as land, capital and labour.

Scope of ForestryEmbraces the production, distribution

and consumption of forest products and services.

Forestry production includes the raising of forest crops such as timber in artificial plantations, or the maintenance of naturally occurring resources to upgrade their productive potential.

Scope of ForestryForestry practised for timber production

is known as silviculture.Production decisions are based on

information about the soil and ecology of the forest; the pests and diseases (pathology) and growth and yield (mensuration) of the trees and the general climatic conditions.

Scope of Forestry The intangible output of forestry production

includes: Protection of soils against erosion and flooding Use of tree vegetation to protect against harsh

local climates and in the improvement of precipitation.

Identification, preservation and maintenance of recreational sites

Landscaping and tree planting in urban areas Prevention of wild bush fires.

Scope of Forestry

Distribution is the primary function of forest industries.

It provides the link between the resource and the user.

Distribution includes:Harvesting and extraction of the

material from the production sitesProcessing and transportation of the

product to the point of use and Marketing forest products.

Scope of ForestryFor some forestry output, such as

recreation, distribution is reversed; consumers are moved to points of production where consumption takes place.

Some physical outputs are consumed without processing e.g. fruit or wood fuel.

Scope of ForestryConsumption of forest products and

services should be carefully studied to take into account the effects of substitute and complementary products.

Consumption information is crucial in determining the scale, form and timing of production.

Scope of Forestry In the case of wood products,

production of raw material takes many years to complete, and accurate estimation of consumption is essential.

In order to meet the needs of the society, forestry cannot ignore the systematic analysis of consumption requirements and the creation of wider opportunities for the utilization of forest products.

Forest ClassificationCategories include: Rural Forest Plantations:

Aim at promoting and maintaining sound environment and growing sustained stock of trees to produce enough fuel-wood, charcoal and other wood products for the population.

The larger part of Kenya's forests is rural forests that are mostly indigenous.

Forest Classification

Industrial Forest plantations: Mainly privately owned for purposes of

wood production for paper manufacturing, building or and furniture making e.g. Webuye Paper Mills with its nucleus plantation for its paper factory.

Urban forest plantations: Include forests such as the Arboretum and

the City Park in Nairobi for environmental protection, aesthetic and recreation.

Forest Benefits Forests provide a wide range of benefits at

the local, national, regional and global levels. Some of these benefits depend on the forest

being left untouched or subject to minimal interference.

Others can only be realized by harvesting the forest for wood and other products.

Yet other benefits from the forests, despite being frequently claimed, are illusionary

Forest Benefits

Include: Wood products Non-wood products Forests as dwelling places Environmental benefits Genetic Resources Biodiversity (Biological Diversity) Global climate

Wood products

Wood and the products derived from it are found in every area of modern existence.

Products include: Timber used in construction and furniture

making. Fuelwood (Charcoal and firewood) for

provision of energy. Fibre for industrial and domestic uses Chipboard, paper, newsprint and cardboard.

Wood products

As a construction material, wood Is strong, light, durable, flexible and easily worked. It has excellent insulating properties.

In contrast to the substitutes of wood such as brick, concrete, metals and plastics wood can be produced and transported with little

energy consumed. wood products are renewable and usually

biodegradable

Non-wood products Forests have primarily been seen as wood-

producing units and other products have conventionally been referred to as “minor forest products”.

However in recent years importance of these products have been given much attention especially in their local context where they may be considerably more valuable than the wood obtained from the forest.

It is recognized that the economic and social importance of these other forest products may be the key to the active involvement of people in forest management.

Non-wood productsNon-wood forest products include:

Plants for food and medicinal purposes Fibre Dyes Animal fodder and other necessities.

The wildlife in forests can also make a major contribution to food supplies.

Non-wood products Non-wood forest products may also be

commercially important at local level, where they are traded in markets and shops or sent to the larger towns and cities

Some of these products are valuable export commodities.

Gums and resins, bamboos, various oils, turpentine, tanning materials, honey, spices, bark and leaves and medicinal plants, and Rattan, the long , thin stem of a climbing palm have become important export commodities in Indonesia.

Forests as dwelling places Forests and woodlands provide a dwelling place for

more that 200 million people in the tropics including: People who have lived there for generations, often

referred to as indigenous or tribal peoples e.g. the ogiek community

People who have recently moved into the area, often described as settlers, squatters or encroachers

People who live part-time in the forest working as small-scale loggers or harvesters of forest products.

The numbers vary with time and among different areas, but all need to be taken into account when forest management is being considered.

Environmental benefits

Forests and woodlands play an important role in protecting the environment at a local and even regional level particularly in steeply sloping watershed areas where the tree roots are important in binding the soil and protecting it against erosion and landslide.

Environmental benefits

Forests also play a major part in areas covered with snow winter.

During the springs, forests help regulate the rate at which the snow melts and also reduce the danger of avalanches.

Environmental benefitsAt local levels trees provide protection against wind erosion. help increase the rate at which rainwater infiltrates

and recharges the ground. help maintain soil fertility of the soil as the nutrients

drawn up by their roots are recycled into the top layers of the soil by leaf fall.

provide shade for animals and humans; the microclimate under trees may be several degrees cooler and more humid than out of their shade.

In coastal areas, mangroves protect the land against erosion by the sea as well as providing breeding grounds for fish and shrimps.

Environmental benefits Forests have an increasingly important role as

havens for wildlife and the protection of endangered species of plants and animals.

Allied to this is their role in recreation, tourism and “ecotourism”.

Hiking, camping, nature study and simply getting out of the city are increasingly important to urban people in their often stressed and polluted world.

Aesthetic appreciation of trees and forests as well as the cultural and spiritual values that they epitomize are very important to rural and urban dwellers alike.

Genetic Resources

Genetic resources refer to the economic, scientific or social value of the genetic variation found among and between species.

If properly managed, these resources are renewable.

Genetic Resources Functions of Genetic variation

Constitutes a buffer against changes in the environment including those brought about by pests, diseases and climate change.

Provides humans with the building blocks for selection and breeding to adapt plants and animals to a range of environments and end uses.

Provides for intensive selection and breeding of crop species for increased yields and uniformity

Genetic Resources The world’s forests are both laboratories for

natural selection of genetic resources of plants and animals, on a scale which cannot be matched by today’s or any conceivable future research stations, and dynamic storage banks for those genes.

In an era of increasing pressure on resources and significantly changing environmental conditions, they provide one of humanity’s most effective ways of buffering itself against a highly uncertain future.

Biodiversity (Biological Diversity)Biodiversity or biological diversity refers

to the variety of life forms, the ecological roles they perform and the genetic diversity they contain.

It is estimated that the tropical forests contain at least 50 percent or more of all the living species on the planet, including a great proportion of higher plants and mammals.

Biodiversity (Biological Diversity)

No financial value can be placed directly on the almost infinite variety of living species in the forests.

Only a tiny proportion are ever likely to be studied in detail, let alone be found useful to humanity.

Yet the loss of each individual species makes the world a biologically poorer place.

Such a loss affects the inter-linkages and symbiotic relationships with other species.

Global Climate

Because trees absorb carbon dioxide during photosynthesis, reforestation is seen as a means of countering the increase in greenhouse gases in the atmosphere.

Carbon dioxide uptake is greatest in the early years when the rate of growth of the tree is at its maximum and tapers off as the tree reaches maturity.

Eventually the trees in the forest simply act as a carbon store when no further net growth of the forest is taking place.

Global Climate

Areas of forest plantations required to have a significant impact on the amount of carbon dioxide in the atmosphere are colossal.

The effect of planting trees outside closed forests on the global climate and on carbon sequestration will depend upon its scale.

Large-scale tree planting projects in agricultural areas must sequester considerable quantities of carbon as well as provide other environmental benefits

Multiple Roles of Forests

Include:Regulating and optimising the

distribution and flow of water.Conserving and protecting the soil

mantle.Providing habitat and dry season refuge

for the wildlife complex, that along with wilderness value, are the foundations of Kenya's important tourist industry.

Multiple Roles of Forests Are a source of virtually all the nations supply

of building and other poles, fuel-wood, sawn timber, veneers and plywood, pulp and paper.

Provide fruits and fodder for humans and animals.

Provide a wide range of physical and economic benefits at the farm. Managing trees in association with crop and

livestock enterprises enhances the productivity of these enterprises.

Tree culture provides avenues for diversifying sources of farm revenues, hence spreading risk, ensuring

Role of Forests in Economy Include: i) Reservation: The ability to

Maintain and improve the climatic and physical conditions of the country

Regulate water supplies by protecting catchment regions

Conserve the soil by preventing desiccation and movement of soil caused by water and wind

Reserve timber and other products for the future. ii) Industry:

Provide people with fuel-wood and raw materials for building, tools and implements.

Role of Forests in Economy iii) Employment:

In forest management and in forest related industries such as making furniture.

iv) Amenity and wildlife The forests provide habitation to the

wildlife and thus are important for tourism and recreation.

Common Timber species

Indigenous hardwood species include: East African Camphor

A hardwood species found in Mt Kenya and Aberdare Forest and Taita Hills.

It is very strong and resistant to fungi and acids, though not resistant to termites.

It is used for furniture; lorry bodies and boat building.

Cedar: A hardwood found in the Mt. Kenya forest. It is widely used in making lead pencils, telegraph

posts and fencing posts.

Common Timber species

Meru oak A hardwood found in the Mt. Kenya forest and

plantations. It is used for furniture.

Mvule A hardwood found at the Coast, Meru and

Nyanza. It is popular in construction work and furniture

making. It is very resistant to fungi, termites and fire

Common Timber species

Exotic softwoods include: Cypress

Initially from Mexico and planted in plantations in Kenya since 1908.

It is popular for joinery/furniture, flush doors, plywood and boxes.

Pine Originally from California, Mexico and Cuba. Popular for fibreboard, pulp and furniture.

Common Timber species

Gum/Eucalyptus Originally from Australia. Used for electricity poles, joinery,

construction and fuel.Wattle

Widely grown in East Africa for tannin on its bark, poles and posts, firewood and charcoal.

Forestry Industry Problems Include:

Depletion of hardwood stocks Inaccessibility to some sources leading to over-

harvesting in accessible areas Low optimal usage due to lack of integrated forest

industries Low recovery rates of 30-40 per cent due to

technological and labour inadequacies Pollution caused by residue disposal problems

and Specific supply shortages of important types of

wood such as wattle.

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