Agricultural Science · Lesson 7

Forestry, forest management, conservation and agroforestry

JAMBWAECNECO

What the syllabus asks

JAMB: B15 forestry (importance, forest products, regeneration, agroforestry, conservation and deforestation)

WAEC: E1 Forestry (meaning, importance, forest types and products, forest management, regeneration, conservation, problems); E2 Agroforestry (meaning, systems, importance); Practical C5 (identification of forest products and trees)

NECO: E1 Forestry (meaning, importance, forest types and products, forest management, regeneration, conservation, problems); E2 Agroforestry (meaning, systems, importance); Practical C5 (identification of forest products and trees)

What you will learn

Define forestry and explain its importance.
Describe the vegetation zones and forest types of Nigeria.
Name major timber species and forest products.
Explain natural and artificial regeneration and forest management practices.
State causes and effects of deforestation and methods of conservation.
Define agroforestry and describe its systems, especially taungya and alley cropping.
State the advantages and problems of agroforestry.

Key points

Forestry: managing and conserving forests for sustained benefits.
Zones: mangrove, freshwater swamp, rainforest, derived, Guinea, Sudan and Sahel savanna, montane.
Timbers: iroko, obeche, mahogany, afara, opepe, abura; exotics teak and gmelina.
NTFPs: bush mango, honey, gum arabic, rattan, chewing sticks, medicines, fuelwood.
Forest functions: productive, protective (soil, water, climate, carbon, wildlife), social.
Natural regeneration: seed, coppice, suckers; artificial: planting seedlings or stumps.
Plantation tending: beating up, weeding, climber cutting, pruning, thinning.
Management: reserves, inventory, selective felling, fire tracing, licences, research (FRIN).
Deforestation causes: farming, logging, fuelwood, fires, urbanisation, mining, grazing.
Effects: erosion, desertification, floods, biodiversity loss, climate change.
Conservation: protected areas, reforestation, laws, alternative fuels, education.
Agroforestry: trees with crops and/or animals; taungya, alley cropping, home gardens, shelterbelts, silvopasture.
Faidherbia albida sheds leaves in the rains, adding fertility without shading crops.

Start here: Meaning and importance of forestry

Forestry is the science, art and practice of creating, managing, using and conserving forests and their associated resources for human benefit on a sustained basis. A forest is a large area dominated by trees, together with the plants, animals and soil that live with them.

Forests matter to every Nigerian, whether or not they live near one. The firewood or charcoal used to cook in many homes, the furniture in classrooms, the paper of textbooks, the chewing stick, the bush mango (ogbono) in soup, and the rain that falls on farms all link back to forests.

Importance of forests

A. Economic (productive) importance

Timber for construction, furniture, boats, railway sleepers, plywood and veneer.
Fuelwood and charcoal: the main cooking energy for many rural and urban households.
Pulp and paper from softwoods and fast-growing species such as gmelina and pine.
Food: fruits, nuts, leaves, bushmeat (where legal and sustainable), honey, snails, mushrooms.
Medicines: bark, roots and leaves used in traditional medicine and as sources of modern drugs.
Industrial raw materials: gums, resins, latex, tannins, dyes, fibres, rattan for cane furniture.
Employment and income: logging, sawmilling, carpentry, charcoal making, trade in non-timber forest products.
Foreign exchange from export of wood products and non-timber products (e.g. gum arabic from acacia in the north).

B. Protective (environmental) importance

Protect soil from erosion by intercepting rain and binding soil with roots.
Regulate water flow: forests on watersheds feed rivers and reduce floods.
Improve soil fertility through leaf litter and nutrient cycling.
Moderate local climate: shade, humidity, lower temperatures; trees as windbreaks.
Absorb carbon dioxide and store carbon, reducing global warming; release oxygen.
Habitat for wildlife and conservation of biodiversity and genetic resources.
Check desert encroachment in the north (shelterbelts).

C. Social and cultural importance: recreation and tourism (e.g. Yankari, Cross River National Park, Okomu), education and research, sacred groves (e.g. Osun-Osogbo Sacred Grove, a UNESCO World Heritage Site since 2005), aesthetic value.

Worked example 7.1

State four protective functions of forests.

Prevent soil erosion by breaking the force of raindrops and binding soil with roots.
Regulate stream flow and reduce flooding on watersheds.
Act as windbreaks and check desert encroachment.
Store carbon and moderate climate (accept: maintain soil fertility through litter; preserve wildlife habitat).

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Practice questions

1. Forestry is the

management of forests and their resources
rearing of fish
growing of flowers
keeping of bees

Show answer

A: management of forests and their resources
It includes conserving and using forests.

2. Which is a protective function of forests?

supplying timber
supplying fuelwood
providing poles
preventing soil erosion

Show answer

D: preventing soil erosion
Productive functions supply goods.

3. Mangrove forests are found mainly in

the Jos Plateau
the Sudan savanna
coastal swamps of the Niger Delta
the Sahel

Show answer

C: coastal swamps of the Niger Delta
Mangroves tolerate salty, waterlogged mud.

4. Which is a non-timber forest product?

railway sleepers
gum arabic
plywood
sawn planks

Show answer

B: gum arabic
Others: honey, rattan, bush mango, medicinal plants.

5. An exotic fast-growing tree used for pulp and poles in Nigeria is

Gmelina arborea
Iroko
Obeche
Mahogany

Show answer

A: Gmelina arborea
Teak is another common exotic.

Key words

Forestry: The science and practice of managing forests and their resources for sustained benefits.
Forest reserve: An area of forest set aside and protected by law for timber production and conservation.
Afforestation: Establishing a forest on land that has not recently carried forest.
Reforestation: Replanting trees on land from which forest has been removed.
Deforestation: The permanent removal of forest cover for other land uses.
Silviculture: The growing and tending of forest trees.
Regeneration: The renewal of a forest, naturally or by planting.
Coppicing: Cutting a tree near ground level so that new shoots grow from the stump.
Selective felling: Cutting only mature trees of chosen species and size, leaving the rest.
Clear felling: Cutting all trees in an area at once.
Rotation (forestry): The period between establishment of a stand and its final harvest.
Taungya: A system in which food crops are grown between young forest trees during plantation establishment.

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