forests Flashcards
productive forests
⅓ of Paks forests = productive forests
These are mainly natural forests where tree density is high & canopy is closed
Great commercial value
Mainly used for extraction of timber & other products
protection forests
⅔ of Paks forests = protection forests
Mainly planted by ppl & usually linear
Include amenity planting along roads, in parks & beside railway lines
Little commercial value as most of them are not valuable timber species
Main function: to protect soil & prevent it from eroding or blowing away
Help to keep environment pleasant by providing shade for ppl
importance of forests
Ecological pov:
Help to maintain a balance in environment by checking pollution & protecting the soil from erosion by wind or water and by intercepting rainfall, esp on sloping ground
Regulate amount of water flowing into river valleys thus reducing floods
Decomposition of leaves helps to form humus which maintains fertility of the soil and helps farmers to grow healthy crops
Natural habitat for wildlife
Commercial & industrial pov:
Provide raw materials to industries making timber products, pharmaceuticals & paper
Valuable for recreation & tourism
Human pov:
Firewood
Supply of wood
Provide recreation
Employment for ppl in forest based industries
Regulate water supply to reservoirs
Type & distribution of forests = closely linked to altitude
In areas above snow line theres hardly any vegetation
Just below snow line = alpine forests
types of forests
Alpine forests: northern areas (Chitral, Dir, Kohistan)
Coniferous forests:
Northern areas
Khyber Pakhtunkhwa (Abbottabad, Mansehra, Kohistan, Shangla, Swat)
Rawalpindi, Islamabad, Murree
Balochistan mountains (Quetta & Kalat divisions)
Tropical thorn forest (rakh):
Punjab plains
Southern & western balochistan
Sindh plains
Sub-tropical scrub forest:
Hills & foothills of lower himalayas
Sulaiman & kirthar ranges
Western mountains (Peshawar, Waziristan, Kohat, Mardan)
Above the Makran coast range
Riverain or Bela forest: river indus and its tributaries
Mangrove forests:
Coastal areas of Sindh
Coastal areas of balochistan (Deltaic regions)
Irrigated forests:
Changa manga near lahore
Wan Bachran in the Thal area
Chichawatni in Sahiwal district & Ghulam Muhammad & Guddu Barrages
irrigated plantations in Pak - advantages and disadvantages
Advantages:
Source of timber for construction, fencing & firewood
Leaves of the tree provide food for animals
Fallen leaves form hummus and increase soil fertility
Transpiration from leaves = more rainfall & lowers temperature
Provides shade/ shelter for ppl & animals
Absorb carbon dioxide and release oxygen
Adds to scenic beauty of the area & promotes tourism
Control surface run off & soil erosion
Provide employment to ppl in forest related jobs
Protect agricultural crops by providing shade & reducing water losses
Eucalyptus trees can reduce water logging & salinity
Disadvantages:
Needs high initial investment but does not give quick returns or profits (no short term economic benefit)
Trees need to be maintained and taken care of thus money is needed on regular basis
Need water = extra burden on limited supplies
Loss of land for settlement/farmland/industries
Illegal cutting of trees = difficult to check
Forest fires = damage to environment
determinants
Alpine forests = extreme north
Mangrove vegetation = south
Density and type of forest = closely linked to rainfall, temperature, altitude & soil type
Areas w diff altitudes have diff types of forests
Aridity ( Balochistan plateau & southern Indus plain) = not favorable to plant growth and results in thorny bushes & scrub
Higher precipitation (northern mountains) encourages coniferous (evergreen) forests
(salt water of Indus & Hab deltas) deposition of alluvium = encouraged growth of mangrove vegetation
Edaphic factors (soil type) determine type & density of forests and diff areas
Coniferous forests consist of species like Spruce and Fir in high altitude areas which have adapted to the severe climate conditions and poor soil
They are softwoods and are used to make paper
After the foliage and bark have been removed from the trunk the wood is ground up and treated w chemicals to produce the pulp needed to make paper
how do mangrove trees survive in salty water?
Internal tissues = v salt tolerant
Roots filter out most of the salt from the water they absorb
Excess salt = carried to the leaves and excreted unto their surfaces
Certain species have gnarled and knobby knees that protrude above the surface of salty mud in which the trees grow. Scientists believe that the mangrove knees extract oxygen from the air and funnel it to the roots below
Conservation and sustainable development of mangrove forests:
Construction of dams and barrages on Indus = reduced amount of water reaching delta from 250 m km3 to 100 m km3
This water and the silt it carries is needed to maintain a balanced ecosystem in the delta
W less water flowing in, more salt from sea is able to flow in, destroying local agriculture and wildlife
Many animals depend on mangroves including endangered species such as turtles
Indus delta = worlds 7th largest mangrove forest
Large areas have been lost due to:
Reduced influx of fresh water and silt
Deforestation for fuel and timber
Pollution from farms, sewage and shipping
Building of roads and other construction projects by the coast
As a result an environment that is extremely important for the growth and health of marine resources has been vanishing fast
Fishing communities suffer badly when tropical cyclones hit the coastal areas
Tidal waves and erosion destroy peoples homes and rice farms
Damage could be reduced if the coast was fringed with mangroves as high waves lose up to 75% of their force after passing thru 200 metre mangroves
Mangroves provide nursery for several species of fish
Their fallen leaves and twigs give rise to a fertile and beautiful habitat in the estuaries (arm of sea at mouth of river)
Young fish and shrimps grow in these estuaries
Mangrove forests also produce honey from the blossoms of the avicenna marina species that constitute 95% of mangroves lining our coasts
International union for conservation of nature (IUCN)has been working to protect and rehabilitate the ecosystem and its resources
Started planting mangroves in coordination w the Sindh forest department in the late 1980s
It is imp that other govt departments and ngos should participate in these initiatives
forest products
Timber, fuel wood etc
Timber: making buildings, furniture, agricultural tools & boxes
Demand for timber= increasing due to increase in population
Other products
Resin: fluid in the tissue of a plant that becomes solid when exposed to air; used for making varnishes
Mazri: mats, baskets, packing material
Ephedra: medicinal shrub used by pharmaceutical factories
deforestation in Pak
Clearing forest land = deforestation
Causes:
After the construction of dams and barrages to provide irrigation water, millions of hectares of forest were cleared to grow crops to feed the growing population
Firewood used in rural and urban areas of Pak
Trampling and uncontrolled grazing by 86M cattle, goat and sheep→ converted sub tropical scrub forest and tropical thorn forest areas into deserts
Growth of cities = replaced forests w suburban housing
Industrialization and urbanization = demand for better transport facilities. Pak = road transport preferred. In many areas roads have been built thru forests
Pak has big domestic and foreign market for wood based products such as sports goods, hardboard, plywood etc. wood is also required as construction material. Buses, boats and railway coaches also consume wood
Effects:
Degeneration and destruction of environment and loss of food resources
Exposes soil to forces of wind and water (esp on foothills) = topsoil eroded by wind and rain = infertile coarse sand
Heavy rainfall = water gushes down the slopes carrying large quantities of silt and sand. No trees to hold soil tgt and slow water flow = surface run off = heavy floods
Large amounts of silt carried downstream can accumulate in reservoirs = reduced reservoir capacity = disrupted generation of hydroelectricity; deposition also harms fisheries
Cutting of trees disturbs natural environment = natural habitat destroyed = disturbed wildlife = extinction
Less vegetation = less evapotranspiration = climate change = less rainfall = lower crop yields
solutions to the problems created by deforestation
Supplying irrigation facilities to deforested areas w effective enforcement of regeneration programmes. Commercial species of trees which grow rapidly should be planted
reserving land for fuel wood plantations only so that valuable species of trees could be saved
Public awareness by govt agencies, NGOs and community workers abt hazards of deforestation
Supply of natural gas to northern areas thru discovery of new gas fields or import from neighboring countries will make life easier for ppl. Rapid deforestation = local ppl, esp women, trudge every greater distances on foot to forage for firewood which they have to carry home in heavy bundles. Local availability will put end to this
Improving growing and planting techniques = deforested area regenerated in short period
Forest managers should try to find a way to make forestry more sustainable eg by:
Ensuring logging companies only use selective cutting methods
Restricting use of heavy machinery in forest
Strict enforcement of forest laws
Enforcement if village/farm forestry programmes
Urban forestry programmes which including planting of trees along main roadsides and in open spaces
Planting fruit trees on slopes of hills = provide food for local ppl & protect soil from wind and water erosion. Terracing, replanting of trees, strip cultivation etc. (fig)
Encouraging ppl to reuse and recycle timber, paper, card = reduced demand for wood = slow rate of tree felling
Developing renewable energy resources eg wind and solar power = reduced demand for wood as fuel = improve air
afforestation projects in Pak
Main objective: afforestation of ecologically critical areas
Includes
Selecting areas to be afforested
Managing plantations
Developing ways of using forest products
Tarbela/Mangla watershed management project:
Aims at afforestation of privately owned badlands in catchment areas of tarbela and Mangla dams
Soil conservation, establishment of orchards & sustainable agriculture = other main components of this project = reduced siltation rate in Mangla dam
Governments Rs34 million ‘Rachna Doab afforestation project:
Planted trees in the region bw Ravi and Chenab rivers
Billion tree tsunami project:
Reafforestation of KPK, a province that has suffered badly from overgrazing, intensive logging & destruction of trees for fuel wood.
Project set out in 2015 to increase KP’s forest area by 2% by 2021 and planted billion trees in its first two years
Environmental benefits + 500,000 jobs created in nurseries & businesses linked to planting
sustainable forestry
World commission of environment and development (WCED) gave one of the most widely accepted definitions of sustainable development in its 1987 report
Def: that “ which meets the needs of present without compromising the ability of future generations to meet their own needs”.
Means resources should be used in such a way that not only the present generation benefits from it but the future generation can also continue to benefit from it
Sustainable forestry means managing resources in such a way to ensure that we will be able to obtain things we want from the forest on a regular basis while also conserving the natural environment.
It implies continuous production of resources such as wood, water, wildlife habitat, recreational opportunities etc.
Ways it can be managed:
Trees vary in their rate of growth to maturity, mainly due to varying climate conditions. They must not be cut down at a rate faster than they can be replaced; e.g if in an area, trees take 30 years to mature, no more than 1/30th of the forest should be cut down in any one year
Every tree cut down must be replaced with a sapling from a nursery
When areas of forests have to be cut down for essential human requirements e.g housing, schools, roads, new areas of forests must be planted to replace them. Such afforestation is also necessary if the industry is to expand and if Pak is to achieve a higher percentage of forests than the present 1.85% of its total area.
