Forest productivity based on soil type

[Larry]

Trying to rate two parcels of land as to which has the best capability for producing fiber.  USDA has a handy dandy calculator which gives either a rating for forest productivity (cubic feet/acre/year) or a tree site index...users choice.  First is the calculator a worth while tool?  Second the rating is given as a number say for the tree site index.  What does the number mean?  This particular site is 61 on the ridge ground and moves to 73 near the streams.  From looking at the existing stand of trees I would rate it as maybe poor to average.

This stuff probably over my head but it is interesting.

Url for the calculator...http://websoilsurvey.nrcs.usda.gov/app/

And a screen shot of where I was at.

[WDH]

Larry,

Tree site index numbers are useful.

The USDA generally uses site index based on 50 years of growth.  Site index is the average height that the target trees will grow to in 50 years.  The higher the site index, the taller the trees at the target year (and therefore the greater the productivity of the site).  I do not believe the numbers given for site index in the Web Soil Survey are absolute, but they are useful for comparing two different soil types.  So, the site index on the uplands is 61 (61 feet of height growth in 50 years) and the site index in the bottoms is 73.  Clearly, the bottom lands are more productive as you would expect. 

I like the Web Soil Survey, and use it a lot to evaluate land.

[Ron Wenrich]

Other things that will come into play is slope and aspect.  The best quality timber grows in northeast and northwest facing hollows.  They are moist all year long.  They don't dry out from the summer sun.  They're pretty protected from bad weather.

But, if you're in flatlands, that doesn't matter too much.

[Ron Scott]

Yes, the Survey Survey information and soil productivity information for your specific area is very useful information and a basis from which to guide your land and resaource management planning and management activities.

I use this information on a regular basis.

[SwampDonkey]

Yeah, depends on landscape position, local climate, soil properties and aspect. Not all bottom land is highly productive. Some is very wet and with poor soil aeration leading to stunted growth and discoloration. Also, some species do better on some sites than others. But, the most productive sites are generally on lower landscape positions.

For example, planting balsam fir on poor drainage sites would be suicide, but tamarack will flourish like the dickens.  Of course tamarack will do best on the best possible sites, don't misinterpret the results. ;)

We have a soils classification system here in NB, but it's not used directly. In my area, most of the time the site is assessed by the tree growth present and how the wood can be extracted the cheapest.  Harvesting is dictated by the quality of timber, changing seasons, watercourses, demand for fibre, $price$, farming and inheritance taxes. The end result is most often a high grade or clearcut.

[tonich]

We have a soils classification system here in NB, but it's not used directly. In my area, most of the time the site is assessed by the tree growth present and how the wood can be extracted the cheapest.  Harvesting is dictated by the quality of timber, changing seasons, watercourses, demand for fibre, $price$, farming and inheritance taxes. The end result is most often a high grade or clearcut.

We have it here too.
The idea is very similar.


PS. One thing, I’m jealous of is the wonderful online information, you have in USA.  :-\

PS2. No clearcuts.  ;D