December 5, 2022

Processes operating on the exterior of the earth resulting in the formation of natural physical features. These are: weathering mass wasting erosion transportation deposition Weathering Mechanical breakdown or chemical decay of rocks “in situ” (without movement) Agents of weathering -Things that work to cause it: Weather elements: rainfall temperature frost gases e.g. CO2,O2 Plants Animals People Factors That Influence Weathering Climate Different areas with different climatic elements experience different types of weathering e.g. block disintegration are experienced in arid areas while frost action is experienced in temperate regions and mountainous regions of tropics. Topography Weathering is faster on steep slopes than on gentle slopes because weathered material is washed away quickly exposing the rock once again to agents while on gentle slopes materials remain in one position shielding the rock from weathering agents. Nature of rocks Dark coloured rocks absorb more heat than light coloured ones hence break faster due to excessive expansion and contraction. A rock with different minerals may disintegrate faster due to differential expansion and contraction of minerals. A well jointed rock will break faster because physical and chemical agents can penetrate faster e.g. by freezing and thawing. Fine textured rocks have a large surface area on which chemical processes can act e.g. Limestone. Biological organisms Bacteria facilitate rotting of organic matter producing organic acids which reacts with some minerals causing the rock to break up. Plant roots and burrowing animals penetrate rocks resulting in cracks providing passage for agents such as water to act on rocks. People accelerate the rate of weathering by exposing rocks buried deep below by digging, blasting and drilling. Types of Weathering Mechanical Weathering – Physical break up of rocks without change in their chemical composition. Processes Block Disintegration/Separation Breaking of rocks into blocks along the joints. It‟s effective in arid areas because of great diurnal temperature range. Day, well jointed rocks are subjected to intense heating causing minerals in it to expand. o In the night the rock is cooled causing it to contract. The rock joints enlarge due to the alternating cooling and contraction. The process is repeated over a long time causing the rock to disintegrate into blocks along the joints e.g. Mundanda rock in Tsavo East. Exfoliation Peeling off of layers of rocks. Also common in arid areas. Day, rock surface is heated more than inner layers because rocks are poor conductors of heat. o The surface expands more than inner layers causing strain between the two layers. With time outer layer develops cracks and later peels off and pieces of rocks fall down under gravity e.g. along Mombassa-Nairobi road between Mtito Andei and Voi. Granular Disintegration Disintegration of rocks into grains. Occurs in rocks with different minerals. When the rock is heated, different minerals expand differently. Internal stress results and with time the rock disintegrates into grains. Pressure Release/Sheeting/Unloading – Disintegration of rocks due to expansion when weight is removed from over it. Soil and other materials lying on top of a rock are removed by erosion and mass wasting (denudation). o The exposed rock expands when the weight that was pressing it is removed. o The outer layer curves and eventually shells are pulled out from the rock. The result is formation of a high rocky hills called granitic tors e.g. Maragoli and parts of Machakos. Frost Action Breaking of rocks into angular blocks due to repeated freezing and thawing. Common in temperate regions or mountainous regions of tropics where temperature fall below zero. Water from melting ice collects into small cracks of rocks. o It freezes and expands and exerts pressure on cracks widening them. o Repeated freezing and thawing causes the rocks to break into angular blocks e.g. on Mt. Kenya, Kilimanjaro and Ruwenzori. Crystal Growth – Break up of rocks due to crystal growth. It occurs in arid areas. High rate of evaporation draws out moisture and dissolved minerals from the rock interior through capillary action. The moisture evaporates when it gets to the surface of the rock leaving behind crystals in the cracks and pores of rocks. The crystals continue to grow exerting pressure on the cracks or pores widening them and eventually causing the rock to break down e.g. at Hells Gate near Naivasha. Slaking/Rain Water Action – Breaking up of sedimentary rocks due to alternate wetting and drying. When it rains, the rock absorbs water and swells. When dry season comes, the rock loses water and the outer surface shrinks. The process is repeated and the minerals become loosely attached to another e.g. in Kenyan Coast at Tudor and Miritini areas. Chemical Weathering Weathering involving changes in the chemical composition of minerals making up rocks Processes 1. Solution Break up of rocks as a result of dissolving of minerals in water without chemical change in them. o Rain water falls on rocks with soluble minerals. o The minerals are dissolved and carried down in solution. o The rock gets weakened and crumbles. 2. Carbonation Weathering caused by reaction of calcium carbonate in rocks with rain water containing a weak carbonic acid. Common in temperate regions. Rain water absorbs small quantities of carbon dioxide forming a weak carbonic acid. H2O+CO2àH2CO3 The weak carbonic acid falls on limestone rocks reacting with calcite forming calcium bicarbonate. CACO3+H2CO3àCA (HCO3) Calcium bicarbonate is removed from the rock in solution. 3. Hydrolysis Weathering caused by reaction of hydrogen ions of water and ions of rock minerals. Igneous rocks are greatly affected. 4. Oxidation Weathering in which minerals in rocks combine with oxygen in the presence of moisture to form new minerals. Rocks containing iron are affected. Ferric oxide is formed on the rock surface which appears as a soft brown or red earth which can be scooped by hands. 5. Hydration Weathering in which hygroscopic minerals in rocks take up water causing them to swell and expand causing disintegration of rock due to internal stress. Biological Weathering – Weathering of rocks due to action of living organisms on them. Action of plants Mechanical The roots

Description of Relief Describe the general appearance of the entire area e.g. hilly, mountainous, plain, undulating landscape, has many hills, isolated hills, etc. State the highest and lowest parts of the area. Look out for valleys which are occupied by rivers. Divide into relief regions such as plateau, escarpment and lowland. Explain the type of slop e.g. gentle, steep, even or irregular. Direction of slope. Identify the land forms present in the area.   Gentle Slope Slope is the gradient of land surface. Gentle slope is one in which land doesn’t rise or fall steeply Contours are wide apart Steep Slopes Where land rises or falls sharply – Contours are close to each other Even Slopes – Shown by contours which are evenly spaced. Uneven Slopes – Indicated by unevenly spaced contours. CONVEX SLOPE One curved outwards Indicated by contours which are close together at the bottom and widely spaced together at the top. Concave Slopes One curved inwards. Contours are close together at the top and widely spaced at the bottom. Valley A low area between higher grounds. Indicated by U-shaped contours pointing towards a higher ground. Spur – Land which is projected from high to low ground. Indicated by U-shaped contours bulging towards lower ground. Spurs in glaciated highlands whose tips have been eroded and straightened. Conical Hills Hills are uplands which rise above relatively lower ground Conical hills are small rounded hills Ridges – A range of hills with steep slopes on all sides. A ridge can contain hills, cols, passes or water shed. A Col – A low area which occurs between two hills. A Pass – A narrow steep sided gap in a highland. A Water Shed The boundary separating drainage systems which drains into different directions – Escarpment and ridges often form water sheds. Escarpment A relatively continuous line of steep slopes facing the same direction Has two slopes: a long gentle slope (dip slope) and short steep slope (scarp slope). Description of Vegetation Natural vegetation is classified as woodlands, thickets, scrubs or grasslands. Symbols are given as pictures of vegetation. Types present Distribution Reasons for distribution e.g. seasonal streams, scrub or grassland due to low rainfall. 1. Forests Likely indications of the following in the area: Heavy rainfall Fertile rainfall Cool temperature depending on altitude 2. Thickets and shrubs Seasonal rainfall Poor soil High temperature 3. Riverine trees High moisture content in the river valley Describing Drainage Identify drainage features present Natural drainage features include lakes, rivers, swamps, sea, rapids, water falls, cataracts, springs, deltas, fjords, sand or mud, and bays Artificial features include ponds, wells, boreholes, water holes, cattle dips, cattle troughs, canals, reservoirs, irrigation channels, aqueducts, water treatment plants and man made lakes. Identify main rivers by name Size of rivers-big or small-shown by thickness of blue lines. Give the general direction of flow. Location of water shed if any Characteristic of each feature Permanent Rivers Which flow throughout the year Shown by continuous blue lines Likely indication of: Heavy rainfall Impermeable rocks Seasonal Rivers Which flow seasonally or during the rain season Shown by broken blue lines Likely indication of: Low rainfall River doesn‟t have a rich catchment area Disappearing Rivers Blue lines ending abruptly Likely indication of: Permeable rocks Very low rainfall Underground drainage Identify drainage patterns and description -Drainage pattern is the layout of a river and its tributaries on the landscape. 1. Dendritic -Resembles a tree trunk and branches or veins of a leaf. Tributaries join the main river at acute angles. 2. Trellis Tributaries join the main river and other tributaries at right angles of hard and soft rocks) Common in folded areas where rivers flow downwards separated by vertical uplands. 3. Rectangular Pattern -Looks like a large block of rectangles. Tributaries tend to take sharp angular bends along their course. 4. Parallel Pattern Rivers and tributaries flow virtually parallel to each other Influenced by slope Common on slopes of high mountain ranges 5. Centripetal Pattern Rivers flow from many directions into a central depression such as a lake, sea or swamp. Examples are rivers flowing into some of the Rift Valley lakes such as Nakuru and Bogoria. 6. Annular Pattern Streams (rivers which are small in size) are arranged in series of curves about a basin or crater It‟s controlled by the slope. 7. Radial Resembles the spikes of a bicycle Formed by rivers which flow downwards from a central point in all directions such as on a volcanic cone e.g. on Mt. Kenya, Elgon and Kilimanjaro. 8. Fault –Guided Pattern Flow of river is guided by direction of fault lines Human/Economic Activities Description of Human Activities Identify types Evidence –man made features Reasons e.g. tea-cool temps and heavy rainfall Agriculture 1. Plantation farming Evidenced by presence of: -“C”-coffee Named estates e.g. Kaimosi tea estate 2. Small scale crop farming Cotton ginnery or sheds Coffee hullerlies Posho mills for maize, millet, sorghum Tea factory/store Livestock Farming Dairy farms Veterinary stations Cattle dips Creameries Water holes Dams Butcheries Slaughter houses Mining Symbol for a mine/mineral works Name of the mine Particular mineral e.g. soda ash Quarry symbol Processing plant of a mineral e.g. cement indicates cement is mined in that area Forestry/Lumbering Saw mills Forest reserves Forest station Forest guard post Roads ending abruptly into a forest estate used to transport logs to saw mills Fishing Fish traps Fishing co-operative society Fish ponds Fish hatcheries Fisheries department Fish landing grounds(banda) Manufacturing/Processing Industry Saw mills for lumber products Ginnery for cotton processing Mill for maize, millet, wheat processing Creameries for milk processing Factory for manufacturing or processing a known commodity. Services  Trade Shops Markets Stores Trading centres Transport Land – Roads All weather roads- which are used all year round i.e. tarmac and murrum roads. Dry weather roads- which are used reliably during dry seasons. Motorable trucks- rough roads which are used by people on foot and by vehicles on dry season. Other trucks and foot paths Railways, station, sliding, level crossing lines and railways light

Set cumulative totals for the data each year Draw vertical axis(Y) to represent dependent variable Draw horizontal axis(x) to represent independent variable Label both axis using suitable scale Plot the cumulative values for each year Use values for components to subdivide the cumulative bar The subdivisions are placed in descending order with the longest at the bottom(coffee) Shade each component differently Put title and key Advantages Its easy to construct It has good visual impression There is easy comparison for the same component in different bars because of uniform shading Easy to interpret because bars are shaded differently Total value of the bar can be identified easily Disadvantages It doesn‟t show the trend of components (change over time). Cant be used to show many components as there is limited space upwards Tedious as there is a lot of calculation work involved. Not easy to trace individual contribution made by members of the same bar Poor choice of vertical scale causes exaggeration of bars length leading to wrong conclusions Analysis Coffee was the leading export earner in the five years. Tea was the second leading export earner. Wheat had the lowest export quantity. 1993 recorded the highest export quantity. 1990 recorded the lowest export quantity. nb-leave ahaif apage for example 2 PIECHART/DIVIDEDCIRCLES/CIRCLE CHARTS A circle which has been subdivided into degrees used to represent statistical data where component values have been converted in degrees. 2. Draw a circle of convenient size using a pair of compasses. 3. From the centre of the circle mark out each calculated angle using a protractor. 4. Shade the sectors differently and provide the key for various shadings. Advantages Gives a good/clear visual impression Easy to draw. Can be used to present varying types of data e.g. minerals, population, etc. Easy to read and interpret as segments are arranged in descending order and are also well shaded. Easy to compare individual segments. Disadvantages Difficult to interpret if segments are many. Tedious due to a lot of mathematical calculations and marking out of angles involved. Can‟t be used to show trend/change over a certain period. Small quantities or decimals may not be easily represented.                                                        Analysis The main producer of commercial vehicles is Japan. The second largest producer is USA followed by Russia. The lowest producers were France and West Germany with. PROPORTIONAL CIRCLES This is use of circles of various sizes to represent different sets of statistical data. On the proportional circle for each year use a protractor and mark out the angles 6. Shade the segments and then provide a key. Advantages They give a good visual impression. Easy to compare various components. Simple to construct. Easy to interpret as segments are arranged in descending order. Can be used to present varying types of data. Disadvantages Tedious in calculation and measurement of angles Actual values represented by each component cant be known at a glance Difficult to accurately measure and draw sectors whose values are too small. Comparison can be difficult if the circles represent values which are almost equal. Analysis/Conclusions Diamond was leading in production. The second leading mineral in production was graphite. The mineral with the lowest production was fluorspar. nb-leave ahaif apage for example 2

TOPIC 1 : STATISTICS – Click to view TOPIC 2 : MAP WORK – Click to view TOPIC 3 : EXTERNAL LAND FORMING PROCESS – Click to view TOPIC 4 : HYDROLOGICAL / WATER CYCLE – Click to view TOPIC 5 : LAKES – Click to view TOPIC 6 : OCEANS, SEAS AND THEIR COASTS – Click to view TOPIC 7 : GLACIATION – Click to view TOPIC 8 : SOIL – Click to view TOPIC 9 : AGRICULTURE – Click to view

Forestry is the science of developing and managing forests including cultivating them. Type of Forests Natural forests-which grow by natural means of seed dispersal. Semi-natural/derived/cultivated forests-which is in the process of recovering from interference by man. Planted/cultivated forests-which have been planted by man. Indigenous forests-which are native to a region or which have grown in a region from the beginning. Exotic forests-which have trees which have been introduced to a place from other countries. Other types have been discussed in the chapter of vegetation. Factors Influencing Types and Distribution of Forests Temperature High temperature causes fast growth of trees while low temperature causes slow growth. Rain forests are found at low altitudes which are warmer while coniferous forests are found at high altitudes which are cooler. Aspect Dense forests are found on windward slopes of mountains because they are wetter than leeward slopes and they start at a lower level than on the leeward slopes. In temperate region slopes facing equator have dense forests because they are warmer while those facing the poles have coniferous forests which are adapted to low temperatures. Precipitation There are dense forest where there is heavy precipitation while there is less forest cover consisting of stunted trees in areas with little precipitation. Coniferous forest have cone-shaped crowns to allow snow to slide off so as not to accumulate on the branches and cause them to break off. Soil Deep soils support huge tropical trees while shallow soils support coniferous trees which have shallow and wide spread root system to be able to maximally utilise water on the top soil since the sub soil is permanently frozen. Poor or infertile soils have stunted trees. Human Activities Deforestation and shifting cultivation- man has cleared forests to create room for agriculture settlement etc. which has reduced forest cover on the earth’s surface. Afforestation and Agroforestry-man has planted trees in areas where they never existed establishing forests there. Reafforestation-man has replanted forests which he has cleared with indigenous and exotic trees causing natural forests to become seminatural/secondary or derived forests. Importance of Forests to Kenya Forests are water catchment areas which supports agriculture and H.E.P. generation. Forests provide us with wood fuel e.g. firewood, charcoal and saw dust. Forests prevent soil erosion by their roots binding the soil together, reducing run off thereby reducing incidents of flooding and dam siltation. Forests are habitats of wild animals which are a tourist attraction which brings foreign exchange used to import goods and services and fund development projects. Forests are a disposal system for carbon dioxide which they use in photosynthesis and release oxygen thereby purifying air and reducing global warming. Forests increase soil fertility when leaves fall and rot forming humus. Forests regulate the climate of an area by creating a micro climate causing heavy and frequent rain by evapotranspiration and lowering temperatures. Forests are a source of timber for construction and furniture making. Forests beautify the environment by flora (plants) and fauna (animals). Some forest’s trees are a source of medicine. Presence of forests has led to the development of infrastructure as roads have been constructed to make forests accessible. Forests provide employment to people e.g. forest guards, forest officers, lumberjacks, carpenters and timber merchants. Importance of Forest Products Forests are a source of food e.g. fruits, honey, mushrooms and bamboo tender leaves which are used for vegetables. Forests provide wood used for manufacture of paper, soft boards, ply wood etc. Animals in forests are hunted for food, skins and horns. Leaves of trees and forest undergrowth are used as livestock fodder. Forests provide wood which is used in cottage industries for making carvings and wooden utensils which are sold locally and exported. Forest flora and fauna are a rich reservoir for research. Problems Facing Forestry in Kenya Encroachment by people by clearing them to create room for agriculture and settlement, grazing etc. which puts some plants and animal species in danger of extinction. Destruction especially of young trees by herbivorous wild animals such as elephants due to rapid increase in the population. Destruction of huge tracts of forests by fires caused by poachers, honey harvesters etc. especially during the dry season. Pests and diseases outbreak which can result in destruction of large tracts of land with valuable tree species e.g. there was an outbreak of aphids in 1980s which destroyed cypress. Overexploitation whereby the trees are harvested at a higher rate than which they are being replaced naturally and also harvesting of immature trees. Excision of forests e.g. by converting some parts of forests into private land, government land like Nyayo Tea Zones and public utilities like Agricultural Show Grounds which has resulted into reduction of the area under forests.   Poor management of forests e.g. clear cutting which may lead to harvesting of immature trees in future, government officials carrying out illegal logging and government in the past having not been strict in forest conservation of forests which led to destruction of large areas of forests. Management and Conservation of Forests Conservation of forests is protection of forests against interference and destruction by man while forest conservation is effective planning and control of forests and forest resources. Conservation Measures Creation of forest reserves to protect indigenous forests from extinction e.g. Mt. Kenya forest, Shimba Hills and Arabuko Sokoke. Setting of forest guard posts in the forests to protect forests against illegal logging (tree felling). Setting Nyayo Tea Zones to act as protective belts to prevent people from trespassing into the forests. They are also a source of employment and foreign exchange. Afforestation and reafforestation. Agroforestry (intercropping of various crops with trees) which: Supplies wood resources Provides animal fodder Provide food e.g. fruits e.g. mangoes and avocadoes for good health and nutrition Acts as wind breakers and  Shade for crops. Management Measures Research to determine which tree species are suitable for which area and how to combat pests and diseases outbreak. Carrying out public campaigns through mass media on the importance of forests. Use of alternative sources of

Plant cover on the earths surface. Types of Vegetation 1. Natural Vegetation Which grows by natural means of seed dispersal without interference and modification by man. 2. Semi- Natural/Derived Vegetation Natural vegetation which is in the process of recovering from interference by man. 3. Planted/Cultivated Vegetation Vegetation planted by people e.g. forests of exotic trees, trees in Agroforestry and plants used as hedges e.g. cypress. Factors Influencing Types and Distribution of Vegetation Topographical Factors 1. Altitude Coniferous trees are found at high altitudes because they are adapted to cool conditions. There is no vegetation on mountain tops because there are very low temperatures which inhibit plant growth. 2. Terrain Gentle slopes which have deep and well drained soils are best suited for plant growth than steep slopes which have thin soils due to severe erosion and less soil water to sustain plant growth due to high runoff. Flat areas have poor drainage hence are swampy and can only support swamp plants. 3. Aspect There are a wide range of plants on the slope facing the sun and in the direction of rain bearing winds as they are warm and wetter. Grass lands are dominant on the leeward side because they are drier. 4. Drainage There is a large variety of plants on well drained soils while water logged soils have swamp plants such as reeds and papyrus. Climatic Factors 1. Temperature Plants in warm areas are large in number and grow faster e.g. in the tropical lands. Also there are deciduous trees which shed leaves to reduce the rate of transpiration. In areas with low temperatures there is slow growth of plants and coniferous forests are found there. 2. Precipitation There are a large number of plants in areas with high precipitation and these areas are dominated by forests which are broad leaved to increase the rate of transpiration. Areas with moderate rainfall are dominated by grasslands and those with little rainfall have scanty vegetation of scrub and desert types. 3. Sunlight There is large number of plants in areas experiencing long sunshine duration. There is little undergrowth in tropical rain forests because the canopy prevents sunlight from reaching the ground. Wind There is heavy rainfall in areas where warm moist blow to and hence a large number of plants which may be broad leaved to increase the surface area for transpiration. Edaphic/Soil Factors Fertile soils have a larger number of plants while infertile soils have scanty vegetation. Soil pollution e.g. oil spillage cause drying up of plants. Deep soils have deep rooted plants such as trees while shallow rooted soils have shallow rooted plants such as grasses and shrubs.  Biotic/Biological Factors 1. Living Organisms Bacteria, earth warms and burrowing animals improve soil fertility resulting into more vegetation growth. Insect and birds pollinate plants enhancing their propagation. Bacteria and insects cause plant diseases of plants resulting in death of some e.g. aphids which affected cypress in late 80s. Large herds of wild animals can destroy vegetation through overgrazing and can turn grasslands into deserts. 2. Human Activities Clearing of natural vegetation for settlement, agriculture etc. can lead to desertification. Bush fires such as burning grasslands for the grass to sprout can cause extinction of some plant species. Overstocking can lead to overgrazing turning grasslands into deserts. Rehabilitation of deforested areas can stop the spread of deserts. Forests The area under forest is less than 7%. The bulk is found in Central Highlands 1. Plateau Forests It used to cover extensive areas around L. Victoria but today there are few patches around the lake in Maragoli, Kakamega, Kaimosi, Malava, Turbo and Tinderet forests. They are tropical rain forests with tall trees standing among shorter trees intertwined with creepers. 2.  Lowland Forests -Found along the Kenyan coast. The main types are: Mangrove forests which grow in shallow waters and Tropical rain forests in Shimba hills in Kwale District and Arabuko Sokoke in Kilifi. 3. Highland/Mountain Forests Found on the slopes of Mt. Kenya, Aberdare forests, Iveti, Mbooni, Kilala and Marsabit forests. Indigenous hardwoods are olive, Meru oak, mvule, Elgon teak and camphor while indigenous softwoods are podocarpus and African pencil cedar and bamboo. They have been planted with exotic hard wood trees e.g. eucalyptus and silver oak and exotic softwoods such as pines, cypress, fir and wattle. Savanna Most widespread vegetation covering about 65% of the total area. 1. Wooded/Tree Grassland Found along the coastal strip and on the plateau bordering highlands east of rift Valley. Consists of grass of 1m mixed with thorny acacias. Where rain decreases trees become fewer and shorter and the grassland becomes more open. There are many large trees along water courses due to abundant moisture (riverine or gallerie forests). The trees shed leaves during the dry season to reduce the loss of water by transpiration. 2. Bushland and Thicket –Covers about 48% of savannah. Found between coastal land and Machakos and extends into Kitui, Mwingi, Garissa, Wajir and Mandera districts. Consists of a mixture of thorny acacias and shorter thorny shrubs between forming thorn bush with gaps between bushes which are bare or covered by scattered varieties of grasses. Plants are adapted by: Having thin leaves and hard cuticle to reduce transpiration rate. Baobab has large trunk to store water for use during long dry period. Shedding of leaves to conserve water. 3. Highland Grassland –Found on the undulating slopes of grasslands. Grasses are such as red oat, wire, Manyatta and Kikuyu grass where forests have been cleared. Clover grows along kikuyu grass where rainfall is over 1000mm. Semi-Desert and Desert Vegetation – Covers about 21% of Kenya. It’s found on the parts of N.E and N Kenya including Marsabit and Turkana districts. It receives insufficient rainfall of less than 380mm annually. It has mainly scrub type of vegetation (covered with underdeveloped trees or shrubs). A shrub is a plant lower than a tree with a small woody stem branching near the ground. The shrubs are up to 1m and grasses are up to 3m