PAIx Lab 1- Assessing Forest Community Structure Flashcards
what was the main goals of this lab
- Structure of ecological communities can give spatial and temporal patterns
- Niche space partitioning
- Use sub-sampling techniques to estimate structure of the entire community (because not feasible to sample entire community)
- Use quadrants
main methods of excersise 1
- Sample five different tree species in forest or residential area.
- Measure diameter at breast height , tree height used inclinometer, and live crown ratio. The identify tree
what is dbh
diameter at breast height (1.35m from the ground
what is live crown ratio
proportion of tree’s height that is green/in crown can be determined with a simple visual estimate
what is relative fequency
number of quadrents containing a given species divided by the sum of the same for all species. Reflects DENSITY of a species and PATTERN DISTRIBUTION, relative to other species
what is relative density
number of individuals of a species divided by the total number of individuals of all species. Depnsity dependant factors (disease, competition, etc) can have a pos or neg correlation to pop size
what is relative dominance
total basal area of an individual species, divided by the total basal area of all species. May be determined by bioecological trait of the most abundant species as well as effects that occur by chance. More abundant = fewer resources that go to subordinate species, and therefor the lower the overall community species richness
what is relative importance value
estimates importance of a sampled species. High importance indicates that species is well represented due to: 1) large number of individuals of spcies compared with other species 2) a smaller number of individuals of the spcies, but the trees are large compared to others.
what is a phytograph
quadriaxial polygonal graph used to present data on spcies performance in vegetation
- Simultaneous visual presentations of 4 individual values while giving integrated picture into relationship
what does rf tell us
- Similar RF: trees found in same number of unique quadrents
what does RD tell us
- Similar RD: similar amount of individuals in the population
- Different RD: number of individuals in the population varies. More= higher RD
what does rdm tell
- Similar RDm: take up similar space (basal area)
- Different RDm: higher RDm= higher total basal area
why would riv be different
- Differences in RIV accounted for in RF, RD, and RDM as it is the mean of them
