﻿118 
  INTRODUCTION 
  TO 
  BOTANY 
  

  

  most 
  profitable 
  to 
  allow 
  the 
  sprouts 
  to 
  grow 
  only 
  twenty 
  or 
  

   thirty 
  years, 
  forming 
  a 
  coppice 
  woodland, 
  which 
  is 
  then 
  cut 
  

   and 
  used 
  for 
  fuel 
  and 
  for 
  making 
  telegraph 
  poles, 
  fence 
  posts, 
  

   and 
  railroad 
  ties. 
  

  

  110. 
  Tree 
  belts 
  and 
  wood 
  lots 
  as 
  windbreaks. 
  Every 
  one 
  

   who 
  has 
  observed 
  the 
  conditions 
  in 
  a 
  country 
  partly 
  wooded 
  

   and 
  partly 
  cleared 
  knows 
  how 
  much 
  less 
  severe 
  is 
  the 
  effect 
  

   of 
  winter 
  winds 
  in 
  areas 
  protected 
  by 
  neighboring 
  woods. 
  

   Cattle 
  that 
  are 
  allowed 
  to 
  range 
  out 
  of 
  doors 
  during 
  cold 
  

   weather 
  always 
  resort 
  to 
  the 
  lee 
  side 
  of 
  wood 
  lots 
  for 
  shelter. 
  

   Most 
  orchards 
  and 
  many 
  crops, 
  such 
  as 
  winter 
  wheat, 
  are 
  

   greatly 
  protected 
  from 
  the 
  effects 
  of 
  destructive 
  cold 
  winds 
  in 
  

   early 
  spring 
  by 
  the 
  presence 
  of 
  trees 
  on 
  the 
  windward 
  side. 
  

  

  Damage 
  from 
  storms 
  which 
  would 
  blow 
  down 
  corn 
  or 
  lodge 
  

   small 
  grains 
  may 
  be 
  almost 
  entirely 
  prevented 
  by 
  suitably 
  

   placed 
  tree 
  belts. 
  It 
  has 
  been 
  computed 
  that 
  a 
  single 
  storm 
  

   in 
  1862 
  damaged 
  standing 
  corn 
  in 
  Illinois 
  to 
  such 
  an 
  extent 
  

   that 
  the 
  loss 
  was 
  almost 
  great 
  enough 
  to 
  have 
  paid 
  for 
  plant- 
  

   ing 
  four 
  miles 
  of 
  tree 
  belts 
  on 
  every 
  square 
  mile 
  of 
  land 
  

   affected 
  by 
  the 
  storm. 
  

  

  Hot, 
  drying 
  winds 
  which 
  parch 
  the 
  crops, 
  and 
  those 
  which 
  

   blow 
  drifts 
  of 
  fine 
  earth 
  or 
  sand 
  from 
  field 
  to 
  field, 
  may 
  be 
  

   made 
  far 
  less 
  injurious 
  by 
  patches 
  or 
  belts 
  of 
  trees. 
  

  

  For 
  these 
  and 
  other 
  reasons 
  it 
  has 
  been 
  found 
  highly 
  profit- 
  

   able 
  in 
  many 
  of 
  the 
  comparatively 
  treeless 
  states 
  to 
  plant 
  

   wood 
  lots 
  and 
  belts 
  of 
  trees 
  in 
  such 
  a 
  way 
  as 
  to 
  afford 
  a 
  sup- 
  

   ply 
  of 
  timber 
  and 
  at 
  the 
  same 
  time 
  protect 
  the 
  cattle 
  and 
  

   crops 
  of 
  the 
  farm. 
  The 
  kinds 
  of 
  trees 
  planted 
  vary 
  with 
  local 
  

   conditions. 
  In 
  general, 
  when 
  protection 
  from 
  winter 
  winds 
  is 
  

   needed, 
  in 
  all 
  the 
  Northern 
  states 
  the 
  belts 
  should 
  consist 
  partly 
  

   of 
  evergreen 
  conifers. 
  1 
  

  

  111. 
  Regulation 
  of 
  the 
  water 
  supply 
  by 
  forests. 
  It 
  is 
  not 
  

   fully 
  known 
  just 
  how 
  much 
  influence 
  forests 
  exert 
  on 
  the 
  tem- 
  

   perature 
  and 
  rainfall 
  of 
  temperate 
  regions. 
  On 
  this 
  account 
  

  

  1 
  See 
  Bates, 
  " 
  Windbreaks," 
  Bulletin 
  S6, 
  Division 
  of 
  Forestry, 
  U. 
  S. 
  Dept. 
  

   Agr., 
  1911. 
  

  

  