commercial thinning question

[Joseph Zorzin]

Vince Zelazny wrote:
> 
> There are two conifer plantations, both of the same species and initial
> density, but plantation A is on a good site, and plantation B is on a poor
> site.
> 
> A commercial thinning guide produced by Stora in Sweden that fell into my
> greedy hands suggests that for both pine and spruce plantation B enters the
> thinning "window" before plantation A does.  That is to say, when plantation B
> achieves basal area X, and average height Y, the recommendation is to thin,
> but for the same BA and height in plantation A, the recommendation is to wait.
> 
> Is there any insight out there as to why this is the case?  Is this
> recommendation based on theory, or is there empirical data supporting this
> approach?  Help me out if you can!
> 
> Vince Zelazny, R.P.F.
> Fredericton, New Brunswick, Canada

The silvicultural guide from Sweeden may not be at all relevant to your 
condition. You should talk to local foresters with a lot experience in those 
forest types.

It may be that since Stand B is on a poorer site it has already reached some 
optimum level of growth and won't put on any further significant growth without 
some thinning.

I'm a forester in western Mass. and mostly work with hardwoods so the above is 
just a wild guess. <G>