﻿219 
  

  

  When 
  all 
  tlie.se 
  indications 
  are 
  present, 
  if 
  the 
  dredging 
  is 
  

   not 
  totally 
  prohibited, 
  it 
  should 
  at 
  least 
  be 
  so 
  limited 
  as 
  to 
  insure 
  

   the 
  proportion 
  of 
  young 
  growth 
  remaining 
  at 
  least 
  one-third 
  

   greater, 
  and 
  great 
  changes 
  from 
  this 
  proportion 
  are 
  to 
  be 
  

   avoided 
  and 
  guarded 
  against. 
  

  

  