﻿Table 
  4.— 
  Comparison 
  of 
  the 
  Ely 
  Utah 
  juniper, 
  Great 
  Basin 
  Utah 
  juniper, 
  and 
  Great 
  Basin 
  singleleaf 
  

   pinyon 
  volume 
  equations 
  with 
  actual 
  volume 
  data 
  from 
  Nevada 
  and 
  Utah 
  BLM 
  districts 
  

  

  Number 
  

  

  BLM 
  

  

  Species 
  

  

  Diameter 
  

  

  of 
  

  

  Actual 
  

  

  Predicted 
  

  

  

  district 
  

  

  

  class 
  

  

  trees 
  

  

  volume^ 
  

  

  volume 
  

  

  Error^ 
  

  

  

  

  Inches 
  

  

  

  

  

  Ft^/tree 
  

  

  Percent 
  

  

  Battle 
  Mountain 
  

  

  Utah 
  juniper 
  

  

  3- 
  9.9 
  

  

  5 
  

  

  0.83 
  

  

  1.07 
  

  

  30 
  

  

  

  

  10-17.9 
  

  

  16 
  

  

  4.32 
  

  

  3.79 
  

  

  -12 
  

  

  

  

  >18 
  

  

  3 
  

  

  14.22 
  

  

  12.78 
  

  

  -10 
  

  

  

  Singleleaf 
  pinyon 
  

  

  3- 
  9.9 
  

  

  26 
  

  

  1.81 
  

  

  1.60 
  

  

  -12 
  

  

  

  

  10-17.9 
  

  

  19 
  

  

  10.76 
  

  

  7.59 
  

  

  -30 
  

  

  Carson 
  City 
  

  

  Utah 
  juniper 
  

  

  3- 
  9.9 
  

  

  6 
  

  

  2.81 
  

  

  1.79 
  

  

  -36 
  

  

  

  

  10-17.9 
  

  

  10 
  

  

  5.15 
  

  

  4.68 
  

  

  -9 
  

  

  

  

  >18 
  

  

  1 
  

  

  12.31 
  

  

  8.73 
  

  

  -29 
  

  

  - 
  - 
  

  

  Singleleaf 
  pinyon 
  

  

  3- 
  9.9 
  

  

  43 
  

  

  2.16 
  

  

  1.92 
  

  

  - 
  11 
  

  

  

  

  10-17.9 
  

  

  26 
  

  

  15.57 
  

  

  10.79 
  

  

  -29 
  

  

  

  

  >18 
  

  

  3 
  

  

  46.32 
  

  

  36.57 
  

  

  -21 
  

  

  Elko 
  

  

  Utah 
  juniper 
  

  

  3- 
  9.9 
  

  

  24 
  

  

  1.11 
  

  

  1.16 
  

  

  4 
  

  

  

  

  10-17.9 
  

  

  25 
  

  

  5.00 
  

  

  4.24 
  

  

  -15 
  

  

  

  

  >18 
  

  

  3 
  

  

  13.04 
  

  

  11.96 
  

  

  -8 
  

  

  

  Singleleaf 
  pinyon 
  

  

  3- 
  9.9 
  

  

  10 
  

  

  1.33 
  

  

  1.22 
  

  

  -8 
  

  

  

  

  10-17.9 
  

  

  5 
  

  

  8.22 
  

  

  7.29 
  

  

  -11 
  

  

  Ely 
  

  

  Utah 
  juniper 
  

  

  3- 
  9.9 
  

  

  19 
  

  

  0.65 
  

  

  0.95 
  

  

  47 
  

  

  

  

  10-17.9 
  

  

  11 
  

  

  5.71 
  

  

  6.25 
  

  

  9 
  

  

  

  

  >18 
  

  

  7 
  

  

  16.30 
  

  

  19.57 
  

  

  20 
  

  

  

  Singleleaf 
  pinyon 
  

  

  3- 
  9.9 
  

  

  17 
  

  

  1.21 
  

  

  1.05 
  

  

  -13 
  

  

  

  

  10-17.9 
  

  

  8 
  

  

  8.85 
  

  

  7.35 
  

  

  -17 
  

  

  Las 
  Vegas 
  

  

  Utah 
  juniper 
  

  

  10-17.9 
  

  

  1 
  

  

  7.77 
  

  

  6.36 
  

  

  -18 
  

  

  

  oingieieai 
  pinyon 
  

  

  1 
  n 
  -17 
  

   1 
  u 
  — 
  1 
  / 
  .y 
  

  

  O 
  

  

  

  H 
  ^ 
  "7 
  A 
  

   1 
  1 
  . 
  / 
  4 
  

  

  - 
  34 
  

  

  

  

  >18 
  

  

  1 
  

  

  55.03 
  

  

  29.02 
  

  

  -47 
  

  

  Richfield 
  

  

  Utah 
  juniper 
  

  

  3- 
  9.9 
  

  

  2 
  

  

  2.05 
  

  

  1.75 
  

  

  -15 
  

  

  

  

  10-17.9 
  

  

  4 
  

  

  8.51 
  

  

  5.84 
  

  

  -31 
  

  

  

  

  >18 
  

  

  2 
  

  

  20.53 
  

  

  15.17 
  

  

  -26 
  

  

  Total 
  

  

  Utah 
  juniper 
  

  

  3->18 
  

  

  139 
  

  

  4.77 
  

  

  4.52 
  

  

  -5 
  

  

  

  Singleleaf 
  pinyon 
  

  

  3->18 
  

  

  164 
  

  

  7.29 
  

  

  5.42 
  

  

  -26 
  

  

  'These 
  are 
  actual 
  volumes 
  computed 
  from 
  tree 
  segments 
  measured 
  by 
  destructively 
  sampling 
  each 
  tree. 
  

   ^Error 
  is 
  predicted 
  volume 
  minus 
  actual 
  volume 
  divided 
  by 
  actual 
  volume. 
  

  

  DISCUSSION 
  

  

  In 
  this 
  study, 
  I 
  searched 
  through 
  a 
  large 
  P-J 
  data 
  set 
  

   and 
  developed 
  easy-to-use 
  volume 
  equations 
  (and 
  tables) 
  

   with 
  standardized 
  measurements 
  for 
  predictor 
  variables 
  

   for 
  the 
  central 
  Rocky 
  Mountain 
  States. 
  However, 
  there 
  

   might 
  be 
  some 
  concern 
  about 
  the 
  reliability 
  of 
  these 
  

   equations 
  from 
  the 
  results 
  of 
  table 
  4. 
  This 
  concern 
  is 
  

   legitimate 
  if 
  the 
  volume 
  equations 
  from 
  this 
  study 
  are 
  

   used 
  for 
  local 
  areas. 
  The 
  discrepancy 
  between 
  the 
  vol- 
  

   ume 
  equation 
  and 
  the 
  volume 
  data 
  given 
  in 
  table 
  4 
  

   clearly 
  illustrates 
  this 
  concern. 
  On 
  the 
  other 
  hand, 
  these 
  

   volume 
  equations 
  are 
  probably 
  adequate 
  for 
  large 
  State- 
  

   wide 
  woodland 
  inventories. 
  This 
  is 
  because 
  the 
  trees 
  

   sampled 
  in 
  an 
  inventory 
  covering 
  an 
  entire 
  State 
  would 
  

   likely 
  represent 
  most 
  of 
  the 
  diverse 
  tree 
  forms 
  used 
  to 
  

   obtain 
  the 
  regression 
  coefficient 
  listed 
  in 
  table 
  2. 
  How- 
  

   ever, 
  local 
  inventories 
  would 
  be 
  less 
  likely 
  to 
  sample 
  tree 
  

   forms 
  matching 
  the 
  tree 
  form 
  occurrence 
  in 
  this 
  study. 
  

   So 
  results 
  such 
  as 
  those 
  in 
  table 
  4 
  might 
  be 
  expected 
  if 
  

   these 
  equations 
  are 
  used 
  for 
  local 
  areas. 
  

  

  I 
  see 
  two 
  possible 
  approaches 
  for 
  future 
  work 
  on 
  P-J 
  

   volume 
  equations. 
  A 
  more 
  precise 
  volume 
  equation 
  could 
  

  

  be 
  sought, 
  or 
  a 
  simple 
  model 
  form 
  such 
  as 
  the 
  one 
  

   presented 
  in 
  this 
  study 
  could 
  be 
  localized 
  for 
  each 
  

   application. 
  

  

  Building 
  a 
  better 
  P-J 
  volume 
  equation 
  may 
  require 
  

   considerable 
  effort. 
  A 
  stem 
  measure 
  that 
  reflects 
  both 
  

   numbers 
  and 
  volume 
  of 
  each 
  main 
  stem 
  of 
  a 
  multiple- 
  

   stem 
  tree 
  may 
  be 
  one 
  avenue 
  for 
  improvement. 
  However, 
  

   developing 
  high 
  precision 
  broadly 
  applicable 
  P-J 
  volume 
  

   equations 
  requires 
  more 
  knowledge 
  of 
  site 
  and 
  tree 
  biol- 
  

   ogy 
  variables. 
  

  

  Development 
  of 
  local 
  volume 
  equations 
  for 
  each 
  appli- 
  

   cation 
  is 
  perhaps 
  the 
  best 
  means, 
  at 
  present, 
  to 
  obtain 
  

   precise 
  P-J 
  volume 
  estimates. 
  This 
  is 
  a 
  fairly 
  simple 
  task 
  

   as 
  a 
  subsample 
  of 
  trees 
  from 
  an 
  inventory 
  can 
  easily 
  be 
  

   measured 
  for 
  volume 
  by 
  using 
  visual 
  segmentation 
  (Born 
  

   and 
  Chojnacky, 
  in 
  preparation). 
  A 
  regression 
  equation, 
  

   volume 
  equation 
  can 
  then 
  be 
  developed 
  that 
  reflects 
  the 
  

   diverse 
  tree 
  forms 
  specific 
  to 
  the 
  area 
  of 
  interest. 
  

  

  There 
  is 
  still 
  much 
  to 
  learn 
  about 
  volume 
  prediction 
  in 
  

   P-J 
  woodlands. 
  This 
  study 
  indicates 
  need 
  for 
  more 
  crea- 
  

   tive, 
  scientific 
  thinking 
  in 
  the 
  future 
  and 
  less 
  massive 
  

   data 
  collection. 
  

  

  g 
  

  

  