Sashelp Data Sets

Tropical Rain Forest Tree Data

The Sashelp.BEI data set contains the locations of 3,604 trees in a number of tropical rain forests (Condit, 1998; Hubbell and Foster, 1983; Condit, Hubbell, and Foster, 1996). A study window of 1,000 $\times$ 500 square kilometers is used. The data set also contains covariates, represented by the variables Gradient and Elevation, which were collected at over 20,301 locations on a regular grid across the study region. The variable Trees distinguishes the event observations in the data set. The following steps display information about the data set Sashelp.BEI and create Figure B.2:

title 'BEI Data';
proc contents data=sashelp.bei varnum;
   ods select position;
run;

title 'The First Five Observations Out of 23,905';
proc print data=sashelp.bei(obs=5) heading=h noobs;
run;

title 'The Trees Variable';
proc freq data=sashelp.bei;
   tables Trees;
run;

Figure B.2: Tropical Rain Forest Tree Data

BEI Data

Variables in Creation Order
#	Variable	Type	Len
1	X	Num	8
2	Y	Num	8
3	Elevation	Num	8
4	Gradient	Num	8
5	Trees	Num	8

The First Five Observations Out of 23,905

X	Y	Elevation	Gradient	Trees
11.7	151.1	.	.	1
998.9	430.5	.	.	1
980.1	433.5	.	.	1
986.5	425.8	.	.	1
944.1	415.1	.	.	1

The Trees Variable

Trees	Frequency	Percent	Cumulative Frequency	Cumulative Percent
0	20301	84.92	20301	84.92
1	3604	15.08	23905	100.00