Site Index and Productivity Flashcards
What trees are used to evaluate site index?
the avg height of the co-dominant trees
What are some contributing factors to total site?
Total site means that all factors that influence growth are considered such as…
- SNR/SMR
- Amount and quality of solar radiation
- Temperature range and averages
- water balance
- elevation and latitude
- slope and exposure
- biological activity
What age is used as a benchmark for SI?
50 years
What is important to note when using indicator species as a estimate of productivity?
Presence, abundance and vigor of the species must be high
What is site index?
Site index is a measure of a sites wood fiber producing capability as a fuction of tree height at a given age.
uses the average height of co-dom trees since dominant trees may have more to do with genetics than site.
Why is site index important in forestry?
- An accurate measure of site productivity in critical to the determination of AAC and site index based rotations
- Allows land manager to choose the best species for the site that will produce maximum yield.
What stands are SI curves most accurate for?
2ND growth stands - Plantations or natural stands from 30-100 years old.
Why are SI curves not reliable for old growth?
Doesn’t take into account decay waste and breakage
How should you determine site index in OG stands?
BEC method (SI by site series appendix of red book)
What method of SI is used for stans age 5-30?
Growth intercept method
What are some problems with the BEC method?
- Site series typing will vary
- Not enough data (small sample sizes)
- Data based on OG stands
What are site index curves best suited to?
even aged, same species middle aged stands that are healthy
What are some indicators that would make a stand unsuitable for site index curves
- Uneven aged
- Sample trees have been overtopped by other trees or brush
- has recieved partial cutting that selected larger trees
- high % of sample trees damaged or diseased
- sample trees are old (ageclass 8 and 9)
- sample trees excessively large and rotten at DBH
What is the growth intercept method
- uses age at breast height to estimate site index in young plantations.
- destructive sampling, increment borer or counting whorls above breast height to get age (but in most cases age of planting is documented)
- Age vs height on growth intercept table
List the SI for good medium and poor sites on the coast
Good: greater than 35m
Med: 20-35m
Poor: less than 20 m
