NATURAL VEGETATION. Forest. Reforestation or Re-afforestaion. Contribution of Forest by Different Provinces. Types of Forest

Transcription

1 Forest NATURAL VEGETATION A large area of land covered with trees and under growth either naturally or artificially. Trees are most important to human because they supply timber and fire wood. They also help to reduce surface runoff, soil erosion and air pollution. Infect it is claimed that % of a country should be covered by forests in order to maintain a balanced economy. So trees must be planted extensively and promoted widely for future generation. In Pakistan only about 4.8 % of total area is forested which is very less. Every year we import large quantity of wood from other countries of the world. In 1947 forest covered only 1.7 % of total land area. So the increase in forest area was achieved by reforestation (re-afforestation) or regeneration programmes. The arid conditions and reckless cutting of the trees account for the low percentage of forest covered areas in Pakistan. Reforestation or Re-afforestaion The replanting of trees to form a forest in an area that was formally forested. e.g. reforestation is usually of coniferous plantation to produce quick growing soft wood timber. Contribution of Forest by Different Provinces NWFP 32 % Northern Areas 25 % Sindh 18 % Punjab 17 % Balochistan 08 % Types of Forest There are two types of forest: 1. Productive Forests 2. Protection Forests 1. Productive Forest (Production Forest) Production forests are those forests which are exclusively grown for production of fruits and medicinal purposes. One third of forest area in Pakistan is covered by productive forests. These forests have great commercial value because they are mainly used for the extraction of timber and other products. 2. Protection Forest Protection forests are those forest which either exists naturally or grown in particular area for the protection of environment. These forests cover two third area and planted along roads, railway track and in parks. The main function is to protect the soil from erosion and to keep the environment pleasant by lowering the temperature and providing shade.

2 Importance of Forest /Advantages 1. Forest prevent soil erosion. 2. Forests regulate water supply in river to prevent floods. 3. Forests check the pollution and provide clean environment. 4. Forests provide raw material for wood based industries. 5. Forests provide employment opportunities in the forest department.. 6. Some plants are used for medicinal purposes. 7. Forests provide recreational facilities and develop tourism. 8. Forest provide natural habitat for wild life. 9. Forest provide oxygen and absorb carbon dioxide. 10. Forest provide shade and fruits. 11. Leaves and branches intercept the rainfall. 12. Leaves fall, decompose and mix with the soil. Determinants There are number of factors that determine the type and density of forests. 1. Areas with different altitude have different types of forests. 2. The arid and semi arid conditions prevailing over the Balochistan Plateau and the southern part of the Indus Plain is not favorable to support plant growth and results in thorny bushes and scrub. 3. Higher precipitation in the northern mountains encourages the growth of trees. 4. In Indus and Hub deltas the deposition of alluvium in the salt water has encouraged the growth of mangrove vegetation. 5. The diversity of topography (type of soil) also determine the type and density of forests in different areas of Pakistan. Tree Line:- The altitude above which no trees grow on a mountain. (below 4500 m) Snow Line:- The altitude above which snow never melts. (above 4500 m) Types of Forest in Pakistan Fig.1 1. Alpine Forest ( 4000 m ) 2. Coniferous Forest ( m ) 3. Sub Tropical Dry or Scrub Forest ( up to 1000 m ) 4. Tropical Thorn or Rakh Forest ( below 1000 m ) 5. Mangrove Forest ( below 1000 m ) 6. Riverain or Bela Forest ( below 1000 m ) 7. Irrigated Forest ( below 1000 m ) Tree line: The altitude above which no trees grow on a mountain i.e. above 4000 m. Snow line: The altitude above which snow never melts i.e m. Determinants 1. The arid and semi arid conditions prevailing over most parts of Indus Plain and Balochistan Plateau. 2. The humid conditions prevailing over parts of the northern hills and mountains. 3. The diversity of topography, ranging from low plains to lofty mountains.

3 Alpine Forest Alpine forest are found above the treeline, at an altitude of 4000 meters, alpine forests are found in the districts of (Distribution) Chitral, Dir, Swat, Shangla, Kohistan and the northern areas. Long severe winters and frequent freezing temperature prevent trees from attaining their full height. The dwarfed and stunted growth of (Species) silver fir, juniper and birch takes place in sheltered nooks. Often, the trees are prostrate. As the mountains rise to the height of the treeline, they become craggy and steep and there is limited area for tree growth. In such a severe climate and difficult topography, alpine forests are found in a limited area. They are not of much economic importance. Features or Characteristics 1. These are evergreen forest. 2. They have long needle shaped leaves. 3. Their branches sloping downwards to prevent the snow accumulation. 4. These trees do not attain their full height. 5. The wood of these trees very soft. Study Photograph A, For Photograph A, Photograph A Q.1. Q.2. Q.3. Name the main type of natural vegetation shown. Alpine / Coniferous forests. Describe the natural vegetation. These are coniferous forests. These are evergreen, tall and straight. Their branches sloping downwards. Their leaves are long and needle shaped. These are soft wood trees with thick bark protection from cold. Explain why there is little or no natural vegetation in area X in the background of Photograph A. In area X there is permanent snow exist due to low temperature. Above the tree line.

4 Coniferous Forest Coniferous forests are found between 1000 and 4000 meters altitude.these forests are found in (Distribution) northern areas districts of Swat, Dir, Malakand and Kohistan. In NWFP, Mansehra and Abbotabad. In Punjab Province Murree, Islamabad and Rawalpindi. In Balochistan Province Quetta and Kalat divisions. Species Fir, Spruce, Deodar, Kail, and Chir. Features or Characteristics 1. These are evergreen forest. 2. These are in conical shape. 3. These forests have sloping branches which prevents snow accumulation. 4. These forests are needle shaped leaves and check excessive transpiration. 5. Trees of these forests are full in height and straight. Photograph of Coniferous Forest Importance Photograph of Coniferous Forest 1. Source of timber, the timber is put to industrial use and for making into furniture and boxes.. 2. These forests protect the environment. 3. These forests are good breeding place for birds and wild life. 4. Add to the scenic beauty of the area. 5. Attract the tourist and promote the tourism industry.

5 Photograph of Thick Bark Photograph of Thick Bark Study Photograph B Photograph B For Photograph B, Q.4. Q.5. Describe in not more than two words the topography (relief) shown in the Photograph. Mountainous / Wooded / Coniferous / Steep slopes. What type of trees are shown in the Photograph? Coniferous. Q.6. At what altitude do these trees grow in NWFP? m. Q.7. How is this type of tree adapted to the climate of this area? Evergreen to take advantage of short growing season and can save energy. Conical shape to shed snow. Small leaves. Thick, leathery leaves to reduce transpiration. Can shed snow with sloping branches. Can tolerate cold with a thick bark Can absorb water from melting snow with shallow roots.

6 Study Fig.2, which shows a map of forest type in Pakistan. Fig.2 Q.8. Name the forest types found in each of the areas A,B and C. A. Coniferous / Alpine Q.9. Explain why the forest type A grows naturally in cool, hilly areas. Evergreen to take advantage of short growing season and can save energy. Conical shape to shed snow. Small leaves. Thick, leathery leaves to reduce transpiration. Can shed snow with sloping branches. Can tolerate cold with a thick bark Can absorb water from melting snow with shallow roots. Sub Tropical Dry Forest or Scrub Forest These forests are located up to a height of 1000 meter.these forests are found on the hills and foothills of Gujrat, Jhelum, Rawalpindi and Attock districts in Punjab and the Mansehra, Abbotabad, Mardan, Peshawar and Kohat districts in NWFP and are covered with dry, evergreen forests. In Balochistan, vegetation in the form of scattered patches of dry mixed scrub, is confined to the Sulaiman Mountains and other hilly areas. Over grazing and heavy firewood cutting, bad agricultural practices, urbanization and lopping had badly affected the original vegetation. Due to shortage of vegetational cover, the area is suffering from excessive rate of soil erosion. The open areas are covered with grass and are useful for grazing. The dominant trees in this region are Phula and Kao. Among the deciduous trees found in this region are the Chestnut, Juniper, Walnut and Oak.

7 Features or Characteristics 1. Dry ever green forest 2. Trees have broad leaves and have umbrella shape with long canopy. 3. Their height is up to 1000 meters. Importance Fire wood Timber Grazing purposes. Study Photograph C For Photograph C Photograph C Q.1. Q.2. Name the type of natural vegetation shown. Sub-tropical dry forest / scrub. Describe the natural vegetation. The natural vegetation consists of small trees and shrubs. Small rounded bushes and clumps of dry grass with bare patches of soil.

8 Photographs of Scrub Forest.

9 Irrigated Forest Photograph of Scrub Forest These forests are man made and are planted under the supervision of Government especially Forest Department. First irrigated forest was planted in 1866 at Changa Manga. The main purpose was to supply wood for railway engines. Some other irrigated forests have been planted in various parts of the country. e.g. Chichawatni. Sahiwal. Thal. Gudu Barrage. Kotri Barrage. Khanewal. Shorekot. Bahawalpur and Sukkur Barrage. After the partition the government of Pakistan has taken special interest for the extension of these forests. But there was a problem for the extension of these forests, that was shortage of water especially between November to March. Common Species 1. Shisham 2. Babul 3. Mulberry Importance Used as a fire wood. Timber. Provide shade in the form of linear plantation. Features / Characteristics Planted in rows / lines. Equal distance between species. Same age / height. Same species.

10 Study Fig.3, the map showing Irrigated forests. Fig.3 For Irrigated Forests Q.3. Name an area; Bahawalpur. Khanewal Changa Manga Kotri Chichawatni Taunsa Barrage Guddu Barrage Thal Hyderabad Shorkot Q.4. Q.5. For irrigated forests describe their main features. Man made and planted in rows Equally spaced. Same age and single species are planted in one block. Near rivers and canals. Main species are Shisham / Babul / Eucalyptus For irrigated forests explain why they were developed in Pakistan. Lack of fuel in the past. Firewood for steam engines / railways. Wood for railway sleepers. Timber for construction / furniture / paper. Firewood for domestic use. To reduce timber imports.

11 Study Fig.4. Fig.4 Q.6. Describe the distribution of Both the areas with natural forests and the irrigated forests shown on Fig.3. Northern mountains / northern NWFP / northern areas. Potwar plateau / Salt Range. Western highland. Indus delta / Sindh coast. Below snowline / 4500 m Areas with wet climate Irrigated Forests Most by rivers / by indus 6/7 in Punjab / most in Punjab / UIP 1 in lower Sindh / LIP 1 on the border ofpunjab and NWFP / confluence of river Indus and Gomal. Q.7. Why are there irrigated plantations of trees in the Indus Plain? Prevent soil erosion of banks. Reduces air pollution. For shade. Reduce timber import. For construction. For firewood. For furniture. For boxes. For agricultural implements.

12 Study Photograph D Photograph D Q.8. Q.9. What evidence in Photograph D shows that this is a plantation? Trees in lines / rows. Same age / height. Same species. Why is the plantation being irrigated? Low rainfall / there is not enough rainfall. Trees need a moderate to good water supply. High rate of evaporation. Q.10. There has been development of forests in lowland areas of Punjab and Sindh using irrigation. Why is irrigation necessary for new plantations of trees? Low rainfall / high evapotranspiration. Seasonal rainfall. Irregular rainfall. Keeps the soil wet / prevents soil erosion. Root system needs to grow.

13 Q.11. Explain the advantages and disadvantages of developing more irrigated plantations of trees in lowland areas of Punjab and Sindh. Advantages Timber for named use e.g. construction, fencing, Firewood. Food for animals / people. Leaf fall for humus / fertility. Rainfall / humidity. Shade / shelter / reduce temperature. Clean air / more oxygen. Scenic beauty / promote tourism. Protection form soil erosion. Employment. Habitat for wildlife. Eucalyptus trees can trees waterlogging and salinity. Disadvantages High cost / long term investment. Cost of maintenance / care. Need for irrigation / more demand on water supplies. Loss of land for housing / farmland. Problems caused by roots, leaves etc. Linear Plantation Planted by man but in a lane. These are found alongside canals / rivers Alongside roads / railways Along field boundaries. Photograph of Linear Plantation. Photograph of Linear Plantation

14 Purpose of Linear Plantation Prevent soil erosion Lower the temperature Provide shade Fruit / food Firewood / timber Leaves / roofing To reduce air pollution / make clean air. Tropical Thorn or Rakh Forest Tropical thorn forests are open, low forests dominated by thorny hardwood trees. In Punjab, especially in the plains, they are characterized by scrub called Rakh which can survive on very small amounts of water. They are also found in Sindh, with scattered patches in southern and western Balochistan. In general, the scrubs are 6 to 10 meters high. Common species include acacia, tamarisk and salvadora. They are primarily used as firewood. Features or Characteristics 1. These forests are thorny hard wood trees. 2. Their height is 6 to 10 meters. 3. They can survive in small amount of water. Importance Fire wood Timber Riverain or Bela Forest These forests are located along the banks of river Indus and its tributaries. Mostly forests are found in Sindh Province and cover the active flood plain. Important species are Babul and Shisham. These are hard wood trees. Fig.4, a map showing the Beal Forest. Fig.4

15 Mangrove Forest These forests are found in Indus Delta, Hub delta and its adjoining areas. These forests can survive easily in salty water, trees are stunted and only a limited number of species grow, due to dumping of industrial, agricultural and chemical waste into the Arabian sea. Important species like Timar, Kirani and Kuni. The general height is about three to four meters. These are called low trees. These forests are good breeding place for fish and shrimps and protect the fish from big waves. The roots of these trees protect the young fish from the predators. Photograph of Mangrove Forest. Importance Indus Delta Wood is used as a fuel. Coastal communities use wood for making boats. Mangrove forests are good breeding place for fish and shrimps. Leaves of these used as a feed for animals (camel). Characteristics These are low trees grown on mud flats. Survive in salty water. General height is about 3 to 4 meter. Stunted growth of trees due to dumping of industrial waste. Q.1. Why is it important that forests by the coast are protected? Breeding ground for fish. Feed amongst roots / protected by roots. Shelter from storms / cyclones. Prevent coastal erosion. Resources for local people e.g. wood for houses, boats, food. Habitat / shelter for wildlife. Under threat from oil spills / over cutting / polluted effluent.

16 Q.2. Why is this type of forest only found in this area (Sindh Coast)? Tidal regular flooding. Saline soil / salt water in soil. Trees are adapted to this environment / roots filter. Salt secreted. Deforestation Cutting of trees or reckless cutting of trees. Causes of Deforestation Urbanization Timber for industry Clearing land for farming Clearing land for fuel purposes Building of roads Over grazing of land. Photograph of Deforestation. Photograph of Deforestation Methods (To overcome the problem of Deforestation) 1. Creating awareness among the people. 2. Supplying irrigational facilities. 3. Improving the techniques of raising nurseries. 4. Planting trees along roads and open places. 5. Provision of Gas to Northern areas. 6. By selective cutting method. 7. Restricting the use of bulldozers during selective cutting method.

17 Selective Cutting Cutting of selected single or group of trees known as selective cutting. Advantages ( Selective cutting ) 1. Reduce over crowding. 2. Save valuable species. Disadvantage ( Selective cutting ) 1. Expensive Effects ( Deforestation ) 1. Soil Erosion due to water and wind. 2. Increase surface runoff. 3. Floods. 4. Loss of crops and property. 5. Silt in reservoir. 6. Disturb of water supply. 7. Less yield. 8. Loss of inhabitant. 9. Pollution. Q.1. Q.2. In many parts of Pakistan forests have been cut down. Describe and explain the effects this deforestation has had on the land and people of Pakistan. No roots to hold soil. Soil erosion. Loss of nutrients. Silting of rivers / reservoirs Rain not intercepted. Floods. Houses destroyed. Bridges washed away. Road / railways washed away. Loss of wood for fuel. Loss of timber for furniture and paper. There has been deforestation within the areas with natural forests. How has this caused problems for: 1. Communication in the mountain areas, 2. Farming on valley floors and plains, 3. Hydro-electric power supplies? 1. Communication in the mountain areas: Soil erosion. Land slides. Flooding. Telephone wires grounded. 2. Farming on valley floors and plains: Soil erosion. Flooding. Canals blocked. Less rain. Crops destroyed.

18 3. Hydro-electric power: Soil erosion. Silt in reservoirs. Less rain. Silt in pipes. Landslides may break power lines. Study Photograph E Photograph E Q.3. Q.4. Study Photograph E, trees have been cut down in area X. What effects may this have on the soil there? Leaching. Soil erosion. Gullying. Land sliding. How can deforestation affect water supplies? Muddy water undrinkable / polluted. Reduced evapotranspiration so less rain. Silt in reservoirs reduce storage capacity. Silt blocks irrigation channels. Flooding / increase surface runoff.

19 Study Fig.5, a map of environmental damage in Pakistan. Fig.5 Q.5. Q.6. Locate the areas most affected by deforestation. North West Borders. NWFP. Northern Balochistan. FATA. State three causes of deforestation in these areas. Firewood. Industry. Road building. Housing / Construction. Mining. Dams. Farming.

20 Study Photograph F Photograph F Q.7. Q.8. Study Photograph F and describe the scene. Bare ground / rocky / barren Steep Slopes. Gullies. Small amount of vegetation. Red colour. Mountains / hills. Badland area. Explain why scenes such as this are caused by deforestation. No roots to hold the soil together. Sil erosion. No interception. More runoff. Loss of leaf fall. Lack of decomposition. Loss of fertility. Less rainfall. More exposure to sun and wind. Leaching.

21 Study Fig.6. Q.9. Fig.6 With reference to Fig.6, explain how deforestation can cause soil erosion. Soil is exposed / lack of protection from leaves and branches. Surface water flow carried soil away. Lack of infiltration into ground. Less water absorbed by roots / less evapotranspiration. No roots to hold soil. No leaf fall to add humus / fertility. Leaching of nutrients / nutrients lost. No new plants grow. Soil Erosion The wearing away of land surface by natural agents i.e. wind, water, rain and glacier. Types ( Soil Erosion ) 1. Sheet Erosion Removal of the upper layer of soil. 2. Rill Erosion When river erode the material from its banks and widen the channel. Methods (To overcome the problem of Soil Erosion) 1. Planting the trees. 2. Terracing. 3. Laying the layer of stone.

22 Photograph of Replanting. Photograph of Terracing. Photograph of Terracing and Layer of stones. Photograph of Terracing and layer of stones

23 Study Fig.7, a map of natural hazards in Pakistan. Fig.7 Q.1. Q.2. Q.3. Q.4. Describe the distribution of soil erosion in Baluchistan. Scattered / widespread / in mountains. Especially in south west of Punjab Province. Central and western part of Khayber Pakhtunkwah. Chagi hills. Northern part and north eastern part of Balochistan. Southern side of Balochistan Province. Central part of Sindh Province. Explain why the dry climate of Balochistan increases the risk of soil erosion. Lack of natural vegetation / bare soil. Slow to re-grow. Wind blows soil away. Over cultivation. Dry soil less cohesive. Where does eroded soil go to? Into rivers / canals. Reservoirs / dams / lakes. On foot hills of the mountains. How can soil be protected in areas of low and unreliable rainfall? Afforestation. Irrigation of the trees. Prevent over grazing. Fill gullies / improved cultivation. Terracing. Laid the layer of stone. Contour ploughing.

24 Forest Products There are two types of products. 1. Major Products ( used as a fuel and timber ) The main sources of timber are Coniferous, Irrigated and Riverain. Fire wood is obtained from trees in general. 2. Minor Products Minor products are the following. 1. Resin It is useful for the manufacturing industries and particularly for the production of Varnish. It is extracted from the Chir which is generally found in NWFP. 2. Ephedra It is used in the manufacture of ephedrine, a drug which is used to treat asthma. 3. Mazri It is used for making mats, Basket and packing material. Sustainable (Meaning) The use of natural products and energy in a way that does not harm the environment. Sustainable Forestry 1. Replanting trees that have been cut down. 2. Looking after forests / maintaining. 3. Planting species that do not need irrigation. 4. Ensuring supplies are there for the future selective cutting. Q.1. Q.2. Why is afforestation called a long-term investment? Trees take many years to grow. Many years before financial return / start production. High cost of planting. Costs during growth. What are the advantages and disadvantages of developing a forest area for tourism? Advantages Employment opportunities Source of income. Provision of named infrastructure / electricity, roads, water, sanitation. Provision of other modern facilities e.g. shops. Reduces the effects of deforestation / destruction of habitats / soil erosion. Disadvantages High cost of development. Damage to trees / effects on habitats. Litter / garbage. Resettlement of local people. Tourist may not come due to problem of security. Loss of culture.