﻿TIMBER; 
  FORESTRY 
  

  

  113 
  

  

  group 
  oaks, 
  elms, 
  and 
  ashes 
  ; 
  in 
  another, 
  oaks 
  and 
  hicko- 
  

   ries; 
  in 
  another, 
  beeches 
  and 
  maples 
  (fig. 
  95). 
  Along 
  the 
  

   fertile 
  river 
  bottoms 
  of 
  the 
  Middle 
  West 
  one 
  may 
  often 
  find 
  

   a 
  combination 
  of 
  sycamores, 
  oaks, 
  ashes, 
  black 
  walnuts, 
  elms, 
  

   and 
  hackberries. 
  

  

  106. 
  Tolerant 
  and 
  intolerant 
  trees. 
  A 
  tree 
  which 
  can 
  endure 
  

   a 
  good 
  deal 
  of 
  shade 
  is 
  said 
  to 
  be 
  tolerant. 
  Examples 
  of 
  this 
  

   are 
  the 
  hemlock 
  and 
  red 
  spruce, 
  among 
  conifers, 
  and 
  the 
  

   beech 
  and 
  maple, 
  among 
  hard 
  

   woods. 
  Trees 
  which 
  require 
  

   much 
  light 
  are 
  said 
  to 
  be 
  intol- 
  

   erant. 
  Examples 
  are 
  the 
  white 
  

   pine 
  and 
  the 
  larch, 
  among 
  

   conifers, 
  and 
  the 
  oaks, 
  hicko- 
  

   ries, 
  and 
  chestnuts, 
  among 
  

   hard 
  woods. 
  As 
  a 
  rule, 
  seed- 
  

   lings 
  require 
  far 
  less 
  light 
  

   to 
  begin 
  life 
  than 
  is 
  needed 
  

   to 
  enable 
  the 
  mature 
  tree 
  to 
  

   reach 
  its 
  maximum 
  size. 
  So 
  

   it 
  often 
  happens 
  that 
  seedling 
  

   trees 
  may 
  survive 
  for 
  years 
  on 
  

   the 
  forest 
  floor, 
  making 
  but 
  

   little 
  growth 
  until 
  the 
  decay 
  

   and 
  fall 
  of 
  overshadowing 
  trees, 
  

   their 
  destruction 
  by 
  wind, 
  or 
  

   their 
  removal 
  by 
  the 
  lumber- 
  

   man 
  enables 
  the 
  seedling 
  to 
  grow 
  rapidly 
  into 
  a 
  large 
  tree. 
  

  

  The 
  relative 
  tolerance 
  of 
  trees 
  is 
  an 
  important 
  topic 
  in 
  prac- 
  

   tical 
  forestry, 
  since 
  the. 
  succession 
  of 
  forest 
  growths 
  often 
  

   depends 
  largely 
  upon 
  this 
  factor. 
  White-pine 
  seedlings 
  could 
  

   not 
  be 
  made 
  to 
  grow 
  under 
  a 
  good 
  stand 
  of 
  pine 
  or 
  hemlock 
  

   timber, 
  but 
  young 
  hemlocks 
  or 
  red 
  spruces 
  would 
  succeed 
  

   there. 
  On 
  the 
  other 
  hand, 
  white-pine 
  seedlings 
  can 
  grow 
  in 
  

   an 
  aspen 
  forest, 
  and 
  white 
  oak 
  and 
  maple 
  seedlings 
  can 
  grow 
  

   in 
  an 
  oak 
  -maple 
  forest. 
  

  

  FIG. 
  95. 
  Primeval 
  deciduous 
  mixed 
  

   forest 
  of 
  maple 
  and 
  beech 
  

  

  