﻿DETERMINING 
  PRACTICAL 
  SPECIES 
  ALTERNATIVES 
  

  

  For 
  the 
  accomplishment 
  of 
  any 
  given 
  ob- 
  

   jective, 
  the 
  theoretical 
  alternatives 
  always 
  

   outnumber 
  the 
  real 
  or 
  practical 
  ones. 
  Theo- 
  

   retically 
  almost 
  any 
  species 
  could 
  be 
  grown 
  

   in 
  the 
  white 
  pine 
  lands 
  under 
  discussion. 
  

   Most 
  species 
  can 
  be 
  eliminated, 
  however, 
  for 
  

   obvious 
  economic 
  or 
  biological 
  reasons. 
  The 
  

   purpose 
  of 
  regenerating 
  stands 
  for 
  timber 
  

   production 
  is 
  to 
  produce 
  a 
  high 
  yield 
  of 
  mer- 
  

   chantable 
  wood. 
  Therefore, 
  the 
  first 
  task 
  in 
  

   evaluation 
  is 
  to 
  make 
  a 
  realistic 
  selection 
  of 
  

   species 
  that 
  seem 
  likely 
  to 
  meet 
  this 
  timber 
  

   growing 
  goal. 
  

  

  The 
  primary 
  factors 
  to 
  be 
  considered 
  in 
  

   choosing 
  a 
  species 
  or 
  species 
  mixture 
  to 
  re- 
  

   generate 
  for 
  timber 
  production 
  are 
  the 
  suita- 
  

   bility 
  of 
  the 
  site 
  for 
  different 
  species, 
  and 
  the 
  

   risk 
  of 
  loss 
  associated 
  with 
  each 
  species 
  dur- 
  

   ing 
  the 
  timber 
  growing 
  rotation. 
  Other 
  fac- 
  

   tors, 
  such 
  as 
  timber 
  quality 
  of 
  the 
  species 
  

   and 
  special 
  treatment 
  requirements, 
  also 
  enter 
  

   into 
  the 
  management 
  decision. 
  

  

  Site 
  Suitability 
  

  

  Habitat 
  Type 
  

  

  The 
  suitability 
  of 
  a 
  particular 
  site 
  for 
  cer- 
  

   tain 
  species 
  may 
  be 
  judged 
  on 
  the 
  basis 
  of 
  

   the 
  habitat 
  type. 
  This 
  classification 
  describes 
  

   an 
  area 
  according 
  to 
  the 
  climax 
  association 
  of 
  

   species 
  that 
  is 
  expected 
  to 
  occupy 
  the 
  area 
  

   generally 
  in 
  the 
  course 
  of 
  natural 
  plant 
  suc- 
  

   cession. 
  Thus 
  it 
  provides 
  a 
  useful 
  basis 
  for 
  

   (1) 
  classifying 
  the 
  ecological 
  character 
  of 
  a 
  

   forest 
  site 
  and 
  (2) 
  describing 
  (to 
  a 
  certain 
  

   degree) 
  the 
  relative 
  biotic 
  productive 
  poten- 
  

   tial 
  of 
  a 
  given 
  site 
  for 
  each 
  species. 
  This 
  is 
  

   especially 
  true 
  in 
  the 
  absence 
  of 
  more 
  defini- 
  

   tive 
  data 
  with 
  which 
  fo 
  estimate 
  the 
  com- 
  

   parative 
  productivity 
  of 
  various 
  species 
  for 
  

   different 
  sites. 
  

  

  Essentially, 
  foresters 
  are 
  either 
  accelerating 
  

   or 
  delaying 
  natural 
  succession 
  of 
  vegetation 
  

   with 
  silvicultural 
  practices 
  designed 
  to 
  im- 
  

  

  prove 
  the 
  forest 
  crop. 
  Because 
  the 
  habitat 
  

   type 
  classification 
  identifies 
  the 
  probable 
  

   plant 
  succession, 
  it 
  is 
  a 
  useful 
  indication 
  of 
  

   the 
  species 
  that 
  should 
  be 
  seriously 
  consid- 
  

   ered 
  for 
  regeneration 
  on 
  a 
  specific 
  site. 
  De- 
  

   termining 
  the 
  habitat 
  type 
  is 
  not 
  simple, 
  but 
  

   it 
  is 
  an 
  essential 
  part 
  of 
  the 
  timber 
  manager's 
  

   job. 
  With 
  training, 
  he 
  can 
  identify 
  the 
  eco- 
  

   logical 
  indicator 
  plants 
  growing 
  in 
  association 
  

   with 
  major 
  tree 
  species, 
  and 
  can 
  relate 
  topo- 
  

   graphic 
  and 
  physiographic 
  site 
  conditions 
  to 
  

   the 
  habitat 
  so 
  as 
  to 
  reach 
  a 
  reliable 
  con- 
  

   clusion. 
  

  

  Species 
  Associated 
  With 
  Western 
  

   White 
  Pine 
  

  

  Western 
  white 
  pine 
  occurs 
  in 
  several 
  habi- 
  

   tat 
  types. 
  It 
  grows 
  in 
  association 
  with 
  a 
  large 
  

   number 
  of 
  species 
  and 
  in 
  a 
  variety 
  of 
  plant 
  

   associations. 
  It 
  occurs 
  only 
  as 
  a 
  serai 
  (suc- 
  

   cessional) 
  species, 
  however, 
  and 
  is 
  eventually 
  

   replaced 
  by 
  more 
  tolerant 
  climax 
  species. 
  

  

  The 
  range 
  of 
  environmental 
  conditions 
  over 
  

   which 
  tree 
  species 
  occur 
  is 
  determined 
  pri- 
  

   marily 
  by 
  moisture 
  and 
  temperature. 
  The 
  

   range 
  of 
  one 
  species 
  may 
  overlap 
  the 
  range 
  of 
  

   another; 
  to 
  the 
  extent 
  of 
  this 
  overlap, 
  the 
  two 
  

   species 
  may 
  be 
  grown 
  together. 
  Figure 
  1 
  

   shows 
  the 
  relative 
  range 
  of 
  conditions 
  under 
  

   which 
  white 
  pine 
  and 
  its 
  associate 
  species 
  will 
  

   grow. 
  The 
  two 
  dashed 
  lines 
  mark 
  the 
  limits 
  

   of 
  the 
  habitat 
  condition 
  range 
  of 
  white 
  pine. 
  

   Other 
  species 
  whose 
  ranges 
  fall 
  at 
  least 
  par- 
  

   tially 
  within 
  these 
  lines 
  could 
  be 
  associate 
  

   species 
  on 
  a 
  given 
  area. 
  The 
  habitat 
  condi- 
  

   tion 
  range 
  of 
  any 
  other 
  species 
  could 
  be 
  

   marked 
  on 
  the 
  diagram 
  to 
  show 
  associate 
  

   species. 
  

  

  The 
  diagram 
  indicates 
  that 
  at 
  lower 
  eleva- 
  

   tions, 
  where 
  the 
  habitat 
  is 
  dry, 
  ponderosa 
  pine 
  

   occupies 
  most 
  of 
  the 
  forested 
  area. 
  Farther 
  

   up 
  the 
  slops, 
  the 
  habitat 
  becomes 
  cooler 
  and 
  

   generally 
  more 
  moist, 
  and 
  Douglas-fir 
  begins 
  

   to 
  mix 
  with 
  the 
  ponderosa 
  pine. 
  Still 
  farther 
  

  

  2 
  

  

  