﻿volumes 
  of 
  merchantable 
  wood. 
  The 
  timber 
  

   manager 
  ranks 
  them 
  in 
  order 
  of 
  preference 
  as 
  

   follows: 
  Douglas-fir, 
  Engelmann 
  spruce, 
  and 
  

   grand 
  fir. 
  He 
  decides 
  to 
  grow 
  a 
  mixed 
  stand, 
  

   so 
  at 
  least 
  two 
  and 
  probably 
  all 
  three 
  species 
  

   should 
  be 
  grown. 
  

  

  Notice 
  that 
  in 
  this 
  example 
  the 
  timber 
  

   manager 
  does 
  not 
  need 
  to 
  make 
  further 
  choice 
  

   between 
  species 
  alternatives. 
  Under 
  different 
  

   site 
  conditions, 
  he 
  might 
  find 
  that 
  he 
  had 
  a 
  

   choice 
  among 
  four 
  or 
  five 
  species. 
  In 
  that 
  

   event, 
  he 
  would 
  follow 
  the 
  evaluation 
  process 
  

   described 
  below 
  for 
  several 
  species 
  mixtures 
  

   — 
  as 
  many 
  as 
  he 
  judged 
  likely 
  to 
  achieve 
  

   the 
  project 
  goal 
  — 
  and 
  would 
  choose 
  the 
  most 
  

   efficient. 
  

  

  Preliminary 
  Estimates 
  

  

  The 
  timber 
  manager 
  now 
  sees 
  two 
  alterna- 
  

   tive 
  plans 
  for 
  regenerating 
  and 
  managing 
  the 
  

   new 
  stand: 
  

  

  A. 
  Clearcut 
  in 
  small 
  blocks 
  (20 
  acres), 
  re- 
  

   generating 
  all 
  three 
  species 
  naturally 
  with 
  

   seed 
  from 
  the 
  residual 
  stand. 
  

  

  B. 
  Clearcut 
  in 
  large 
  block 
  (100 
  acres) 
  and 
  

   regenerate 
  by 
  planting 
  mostly 
  grand 
  fir 
  and 
  

   spruce. 
  Some 
  Douglas-fir 
  will 
  seed 
  in. 
  

  

  In 
  either 
  case, 
  natural 
  seeding 
  of 
  most 
  

   species 
  will 
  probably 
  occur 
  within 
  the 
  first 
  5 
  

   years, 
  requiring 
  subsequent 
  thinning 
  to 
  bring 
  

   about 
  the 
  species 
  composition 
  and 
  proportions 
  

   desired. 
  

  

  At 
  this 
  point 
  in 
  the 
  economic 
  evaluation, 
  

   the 
  manager 
  must 
  decide 
  what 
  alternative 
  

   plans 
  are 
  compatible 
  with 
  the 
  project 
  goal, 
  

   so 
  that 
  he 
  may 
  compare 
  the 
  costs 
  likely 
  to 
  

   be 
  incurred. 
  Of 
  basic 
  concern 
  are 
  the 
  invest- 
  

   ment 
  periods 
  and 
  the 
  cultural 
  treatments 
  to 
  

   be 
  evaluated. 
  For 
  this 
  illustration, 
  two 
  treat- 
  

   ment 
  plans 
  — 
  A 
  and 
  B 
  — 
  are 
  evaluated. 
  

   Costs 
  are 
  estimated 
  for 
  each 
  plan 
  according 
  

   to 
  two 
  time 
  periods 
  and 
  two 
  stocking 
  control 
  

   treatments 
  adapted 
  to 
  these 
  time 
  periods. 
  

  

  General 
  Assumptions 
  

  

  The 
  following 
  assumptions 
  are 
  made 
  in 
  the 
  

   calculations 
  of 
  comparative 
  costs 
  of 
  stand 
  

   establishment: 
  

  

  1. 
  Site 
  preparation: 
  The 
  same 
  standard 
  for 
  

   site 
  preparation 
  applies 
  to 
  both 
  planting 
  and 
  

   natural 
  regeneration. 
  

  

  2. 
  Costs 
  of 
  site 
  preparation: 
  Not 
  including 
  

   slash 
  disposal, 
  costs 
  range 
  from 
  $15 
  per 
  acre 
  

   on 
  20-acre 
  units 
  to 
  $11 
  per 
  acre 
  on 
  100- 
  

   acre 
  units. 
  

  

  3. 
  Seed 
  source: 
  Under 
  natural 
  regener- 
  

   ation, 
  there 
  is 
  a 
  charge 
  to 
  seed 
  source 
  to 
  

   cover 
  the 
  additional 
  costs 
  of 
  sale 
  layout 
  and 
  

   administration 
  entailed 
  by 
  cutting 
  in 
  small 
  

   blocks. 
  This 
  is 
  estimated 
  at 
  $3 
  per 
  acre. 
  

  

  4. 
  Time 
  to 
  stand 
  establishment: 
  Under 
  

   natural 
  regeneration, 
  there 
  is 
  a 
  3-year 
  lag 
  

   between 
  site 
  preparation 
  and 
  stand 
  establish- 
  

   ment. 
  Planting 
  can 
  be 
  completed 
  within 
  1 
  

   year 
  of 
  site 
  preparation. 
  

  

  5. 
  Number 
  of 
  trees 
  planted: 
  On 
  a 
  100-acre 
  

   unit, 
  planted 
  trees 
  per 
  acre 
  average 
  290. 
  This 
  

   assumes 
  full 
  planting 
  (450 
  trees 
  per 
  acre) 
  on 
  

   30 
  acres 
  and 
  an 
  average 
  of 
  225 
  trees 
  per 
  acre 
  

   on 
  the 
  remaining 
  70 
  acres 
  that 
  are 
  likely 
  to 
  

   receive 
  some 
  natural 
  regeneration. 
  

  

  6. 
  Thinning: 
  A 
  precommercial 
  thinning 
  is 
  

   required 
  15 
  years 
  after 
  stand 
  establishment. 
  

   Thinning 
  costs 
  average 
  $35 
  per 
  acre 
  in 
  natural 
  

   stands 
  and 
  only 
  $20 
  per 
  acre 
  in 
  planted 
  stands 
  

   because 
  fewer 
  trees 
  need 
  to 
  be 
  removed. 
  

  

  Volume 
  Yields 
  Assumed 
  

  

  The 
  estimate 
  of 
  gross 
  volume 
  yield 
  is 
  based 
  

   on 
  increments 
  of 
  100 
  cubic 
  feet 
  per 
  acre 
  per 
  

   year 
  for 
  spruce, 
  80 
  cubic 
  feet 
  for 
  grand 
  fir 
  

   and 
  60 
  cubic 
  feet 
  for 
  Douglas-fir. 
  On 
  planted 
  

   areas 
  species 
  distribution 
  is 
  expected 
  to 
  be 
  

   about 
  50 
  percent 
  spruce 
  and 
  50 
  percent 
  grand 
  

   fir. 
  In 
  the 
  natural 
  stand 
  a 
  relatively 
  high 
  

   proportion 
  (60 
  percent) 
  of 
  Douglas-fir 
  is 
  ex- 
  

   pected, 
  with 
  20 
  percent 
  each 
  of 
  spruce 
  and 
  

   grand 
  fir. 
  

  

  Investment 
  period 
  assumed. 
  — 
  The 
  two 
  in- 
  

   vestment 
  periods 
  used 
  in 
  this 
  illustration 
  are 
  

   ( 
  1 
  ) 
  the 
  time 
  required 
  to 
  grow 
  a 
  merchantable 
  

   stand 
  in 
  which 
  nearly 
  all 
  the 
  volume 
  is 
  in 
  

   trees 
  8 
  inches 
  d.b.h. 
  and 
  larger, 
  and 
  (2) 
  a 
  full 
  

   sawtimber 
  rotation 
  of 
  a 
  length 
  required 
  to 
  

   grow 
  trees 
  to 
  the 
  size 
  class 
  objectives 
  cur- 
  

   rently 
  in 
  effect 
  for 
  National 
  Forests 
  in 
  the 
  

   Northern 
  Rocky 
  Mountain 
  area. 
  

  

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