Welcome to our interactive 
Hubbard Brook Phytosociology program!

This program calculates some basic standard summaries about the forest composition at Hubbard Brook, online and on the fly!!  The calculations are for the Valley plots, also known as the "Schwarz" plots, since they were primarily Paul Schwarz's effort.  The 431 plots are each 500 square meters, arranged in a symmetric grid system over the entire Hubbard Brook valley. They were put in as tagged tree plots in 1995 through 1998 and are scheduled to be remeasured in 2005.  Tabular output includes basal area, stem density and species frequency.

Please do not use any of these numbers in any official way without first checking with the Hubbard Brook research team.

If you are losing the page when reloading images in the calculators, please go back to the W6 front page and reenter by clicking "click here if your browser does not support frames".

This program is optimized for Internet Explorer 6.

Valley plots

Please choose a year:
Please choose a health code (vigor):

You may select a diameter range over which you would like to make the summaries. The smallest diameter included in the data is 10 cm and there are no trees over 120 cm dbh. If no diameter range is specified, the program will run for all trees >10 cm dbh. (Note that all trees 10.0 to 10.4 will be doubled. See explanation. We recommend using either integers or a midpoint range (i.e. X.5 to X.4), unless you have read all the notes and understand exactly what the program returns.)
Enter lower diameter (in cm):
Enter upper diameter (in cm) :

Please indicate by number which of the following plot summary options you are going to use (Option 0 includes all plots):  

1 . Choose individual plots (hold down the shift key to select large blocks of plots or hold down the Ctrl key to select several individual plots):
                click here for a plot map

2. OR, enter a lower and upper elevation limit (in meters). The elevation range for the Valley plots is 245 to 910 m. (Please left justify and leave one space between the numbers, e.g. 600 700):

3. OR, enter a range in slope aspect (azimuth compass bearing). For example, for slopes facing due north to southeast, use 0 and 135. (Please left justify and leave one space between the numbers, e.g. 0 135):

4. OR, enter a single plot. Plots in the Valley are numbered 1 to 460 with a few skipped numbers. There are 431 total plots in this dataset :

You may select a particular species for which you would like to see a diameter distribution by 1 cm diameter classes. If a species is not chosen the program will make the summary graph for all species combined.
Please choose a species:

Would you like to identify those plots on which this species is dominant? 
Dominance is measured as the percentage of all trees on the plot this particular species composes. This may be based on either basal area or on stem density as chosen above, and you may choose the degree of dominance you are interested in. Only those trees within the size and vigor classes and plots selected above will be considered in the calculations. This option will not run for "all species combined".
Please choose the units you prefer: 
Please enter the minimum percent this species must occupy. For example, if you are interested in plots that are composed of at least 30% of the selected species, then use 30:
 

Would you like to see the stem count for each species in each plot for the size class and vigor options chosen above?

 

 


Click here for the general overview and details of how all these calculations are being made.

Click here for Tom's very specific miscellaneous notes regarding this calculator.

The data used in the calculations have not yet been made public.

        Please note that this page may undergo changes in the future as we develop new ideas for calculating phytosociology. In the meantime, we welcome any suggestions that you may have for this page at thomas.siccama@yale.edu.

 

[ phyto page | stop 7 | trail map | W6 front page | main HBES homepage ]


Web page created June 2003
by Thomas Siccama and Ellen Denny