North  of  the  fifty-first  parallel  it  gradually  decreases  in  density,  and  south  of  the  forty-third  parallel  it  changes
in  composition  and  character.  This  belt  of  Coast  Forest  is  only  surpassed  in  density  by  that  of  some  portions  of
the  redwood  forest  of  the  California  coast.  The  red  fir,  the  great  tide-land  spruce,  the  hemlock,  and  the  red  cedar
(Thuya)  reach  here  enormous  dimensions.  The  wide  river  bottoms  are  lined  with  a  heavy  growth  of  maple,
Cottonwood,  ash,  and  alder,  the  narrow  interior  valley  with  an  open  growth  of  oak.  In  this  great  coniferous  forest
the  trunks  of  trees  two  or  three  hundred  feet  in  height  are  often  only  separated  by  the  space  of  a  few  feet.  The
ground,  shaded  throughout  the  year  by  the  impenetrable  canopy  of  the  forest,  never  becomes  dry  ;  it  is  densely
covered  by  a  thick  carpet  of  mosses  and  ferns,  often  of  enormous  size.  The  more  open  portions  of  this  forest  are
choked  by  an  impenetrable  growth  of  various  Vaccinew  of  almost  arborescent  proportions,  of  hazel,  the  vine-maple,
and  other  shrubs.  The  soil  which  has  produced  the  maximum  growth  of  forest  in  this  region  is,  outside  the  river
bottoms,  a  thin,  porous  gravel  of  glacial  origin,  rarely  more  than  a  few  inches  in  depth ;  the  luxuriance  of  vegetable
growth,  therefore,  illustrates  the  influence  of  a  heavy  rainfall  and  temperate  cUmate  upon  the  forest.
