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  ANNUAL. 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  match, 
  there 
  are 
  correspondences 
  in 
  climatic 
  cycles 
  to 
  which 
  atten- 
  

   tion 
  will 
  be 
  called 
  later. 
  

  

  Cross-identification 
  is 
  practically 
  perfect 
  amongst 
  the 
  sequoias 
  

   stretching 
  across 
  15 
  miles 
  of 
  country 
  near 
  General 
  Grant 
  National 
  

   Park. 
  Trees 
  obtained 
  near 
  Springville, 
  some 
  50 
  miles 
  south, 
  show 
  

   50 
  to 
  75 
  per 
  cent 
  resemblance 
  in 
  details 
  to 
  the 
  northern 
  group. 
  

   This 
  was 
  far 
  more 
  than 
  enough 
  to 
  carry 
  exact 
  dating 
  between 
  

   these 
  two 
  localities. 
  Cross-identification 
  in 
  some 
  wet 
  climate 
  groups 
  

   was 
  extremely 
  accurate. 
  A 
  group 
  of 
  12 
  logs 
  floating 
  in 
  the 
  river 
  

   mouth 
  at 
  Geffle, 
  Sweden, 
  showed 
  90 
  to 
  95 
  per 
  cent 
  resemblance 
  to 
  

   each 
  other. 
  The 
  range 
  was 
  100 
  to 
  200 
  years 
  and 
  there 
  were 
  no 
  

   uncertain 
  years 
  at 
  all. 
  The 
  same 
  was 
  true 
  of 
  some 
  10 
  tree 
  sections 
  

   on 
  the 
  Norwegian 
  coast 
  and 
  of 
  13 
  sections 
  cut 
  in 
  Eberswalde 
  in 
  

   Germany. 
  A 
  half 
  dozen 
  sections 
  cut 
  in 
  a 
  lumber 
  yard 
  in 
  Munich 
  

   did 
  not 
  cross-identify 
  with 
  each 
  other. 
  A 
  group 
  of 
  5 
  from 
  a 
  lumber 
  

   yard 
  in 
  Christiania 
  was 
  not 
  very 
  satisfactory. 
  A 
  very 
  recent 
  group 
  

   of 
  coast 
  redwoods 
  from 
  Santa 
  Cruz, 
  Calif., 
  proved 
  very 
  un- 
  

   satisfactory. 
  The 
  vast 
  majority, 
  however, 
  have 
  been 
  absolutely 
  sat- 
  

   isfactory 
  in 
  the 
  matter 
  of 
  cross-identification. 
  Nothing 
  more 
  is 
  

   needed 
  to 
  make 
  the 
  one 
  ring 
  a 
  year 
  ideal 
  perfectly 
  sure 
  in 
  the 
  work 
  

   here 
  described, 
  but 
  if 
  there 
  were 
  it 
  would 
  come 
  in 
  such 
  tests 
  as 
  

   frequently 
  occur 
  in 
  checking 
  the 
  known 
  date 
  of 
  cutting 
  or 
  boring, 
  

   with 
  a 
  set 
  of 
  rings 
  previously 
  dated. 
  That 
  has 
  been 
  done 
  on 
  many 
  

   occasions 
  in 
  Arizona 
  and 
  California. 
  To 
  give 
  final 
  assurance, 
  the 
  

   record 
  in 
  the 
  yellow 
  pine 
  was 
  compared 
  with 
  statements 
  of 
  good 
  

   and 
  bad 
  years, 
  and 
  years 
  of 
  famine, 
  flood, 
  and 
  cold, 
  reported 
  in 
  

   Bancroft's 
  " 
  History 
  of 
  Arizona 
  and 
  New 
  Mexico," 
  and 
  it 
  was 
  

   found 
  that 
  his 
  report 
  identified 
  with 
  the 
  character 
  of 
  the 
  growth 
  in 
  

   the 
  corresponding 
  years 
  of 
  the 
  trees. 
  

  

  Three 
  results 
  may 
  be 
  noted 
  before 
  leaving 
  this 
  important 
  subject. 
  

   Deficient 
  years 
  extend 
  their 
  character 
  across 
  country 
  with 
  more 
  

   certainty 
  than 
  favorable 
  years. 
  A 
  deficient 
  year 
  makes 
  an 
  individual 
  

   ring 
  small 
  compared 
  to 
  those 
  beside 
  it. 
  Large 
  rings, 
  on 
  the 
  other 
  

   hand, 
  are 
  more 
  apt 
  to 
  come 
  in 
  groups 
  and 
  so 
  do 
  not 
  have 
  quite 
  the 
  

   same 
  individuality. 
  Nor 
  are 
  they 
  as 
  universal 
  in 
  a 
  forest. 
  If 
  they 
  

   occur 
  at 
  a 
  certain 
  period 
  in 
  one 
  tree, 
  the 
  chances 
  are 
  about 
  50 
  per 
  

   cent 
  that 
  the 
  corresponding 
  years 
  in 
  the 
  neighboring 
  trees 
  will 
  be 
  

   similarly 
  enlarged. 
  If, 
  however, 
  a 
  very 
  small 
  ring 
  occurs 
  in 
  a 
  

   tree, 
  the 
  chances 
  are 
  over 
  90 
  per 
  cent 
  that 
  the 
  neighboring 
  trees 
  will 
  

   show 
  the 
  same 
  year 
  small. 
  

  

  Second, 
  with 
  many 
  groups 
  of 
  trees 
  where 
  the 
  resemblance 
  between 
  

   their 
  rings 
  is 
  strikingly 
  exact, 
  a 
  small 
  number 
  of 
  individuals 
  such 
  

   as 
  5 
  will 
  answer 
  extremely 
  well 
  for 
  a 
  record, 
  and 
  even 
  fewer 
  will 
  

   give 
  valuable 
  and 
  reliable 
  results. 
  But 
  the 
  central 
  part 
  of 
  a 
  tree 
  

   has 
  larger 
  growth 
  and 
  is 
  less 
  sensitive 
  than 
  the 
  outer 
  part. 
  Its 
  

  

  