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SAI INTERNATIONAL SCHOOL
                                        (VIRTUAL CLASSES) – LESSON NOTES

           Class     - IX      Geography
           Chapter - 5       Natural Vegetation and Wildlife


                                        (VIRTUAL CLASSES) - MODULE-2.4



        Photoperiod (Sunlight)


        The  variation  in  duration  of  sunlight  at  different  places  is  due  to  differences  in  latitude,  altitude,

        season and duration of the day. Due to longer duration of sunlight, trees grow faster in summer. In

        India,  almost  the  entire  rainfall  is  brought  in  by  the  advancing  southwest  monsoon  (June  to
        September) and retreating northeast monsoons. Areas of heavy rainfall have more dense vegetation

        as compared to areas of less rainfall.


                Forests  are  renewable  resources  and  play  a  major  role  in  enhancing  the  quality  of

               environment.
                They  modify  local  climate,  control  soil  erosion,  regulate  stream  flow,  support  a  variety  of

               industries,  provide  livelihood  for  many  communities  and  offer  panoramic  or  scenic  view  for
               recreation.

                They control wind force and temperature and cause rains.

                They provide humus to the soil and shelter to the wildlife.
        India’s natural vegetation

              It  has  undergone  many  changes  due  to  several  factors,  such  as  the  growing  demand  for
               cultivated  land,  development  of  industries  and  mining,  urbanisation  and  over-grazing  of

               pastures.

              The vegetation cover of India in large parts is no more natural in the real sense.
              Except in some inaccessible regions, like the Himalayas, the hilly region of central India and

               the  marusthali,  the  vegetation  in  most  of  the  areas  has  been  modified  at  some  places,  or
               replaced or degraded by human occupancy.


        According to India State of Forest Report 2011, the forest cover in India is 21.05 per cent.
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