Regeneration of harvested areas

C.K.Black at massey.ac.nz C.K.Black at massey.ac.nz
Tue Jul 11 05:57:47 EST 1995


G'Day,  I missed the original post on this one but if you bear with me,
  I'll explain what we do in NZ and what I'd like to see more of in the
US Forests.......

> > Can anbody tell me what is the maximum number of generations 
> > that can be grown on land that is harvested using clearcut techniques.

Forestry is similar to a 'closed' system rather than an 'open' system,
such as agriculture, where there is a constant annual removal of nutrient.
Provided there is a replacement of elements after clearcut harvest and a
method to ensure soil retention and structure,  there is no reason to put
a limit on the number of generations that can be harvested.
 
> > How many with the most ecological friendly method? How much more timber 
> > do you get when you clear cut vs eco-friendly cut.
>
>Ecological friendly is a nebulous term. Many times a clearcut will offer the
>great diversity of species - plant and animal. It is emulating nature in many
>ways. Many wildlife species require a diversity of habitats. Openings in the
>forest offer that.

Agreed.  In a limited post I won't offer all the tech background but some
of our native species 'love' clearcut and the introduced mammals become
pests.  

> > If my questions are to general with regards to type of tree 
> > please consider my intrest to be in pine trees

>Same answers apply. Only the harvest cycles are usually closer together - about
>30 years compared to 70-100 years for hardwoods.

We are predominately pines,  P. Radiata, imported from the States, and our
cycles are similar.  We are getting more volume per area,  one due to the
climate,  and two,  because we 'oversow'.   That is,  after clear cutting,
we sow 6 - 20 kg/ha of grass & legume seed onto the overcut areas.  It is
not 'magic' just a common sense forestry tool.  Each seed mix is different
depending on the likely 'weed' spectrum and what the forester needs to 
achieve within his/her silvacuture regime.  When the mix is right, you
get the following;
1)  Weed suppression
2)  Reduced chemical input & cost
3)  Erosion elimination 
4)  N-Fixation for improved tree growth.

The minors (yet to be measured),  are increased soil moisture retention,
decreased C-N ratios for faster 'slash' degradation and decreased fire 
risk, and nutrient cycling.  Have I got an interest in this?  Yuppp..
Up front,  I've been plucked from a PhD. in Ag and told to research
plants in forestry.  Doesn't change the bottom line......
Clearcut.

>Hope this helps.

Me too,  AFPE,  my mandate is 'sustainability'.  Well,  we probably 
have that licked.  Now we just just have to compete on cost.  'Bout
as likely as a nation of 3 M and 60 M sheep taking the America's
Cup off of somebody backed by NASA???  8^)    Cheers,  CB



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