[R] Format Data Issue??

[Randy Cass]

R Users,

I am new to R and have tried to figure out how to automate this
process instead of using excel.  I have read in this dataframe into r
with read.table.  I need to reshape the data from the first table into
the format of the second table.

TractID	StandID	Species	CruiseDate	DBHClass	TreesPerAcre
Carbon	Stand 1	Loblolly Pine	       5/20/2010	10    	1.2
Carbon	Stand 1	Loblolly Pine	       5/20/2010	12    	1.2
Carbon	Stand 1	Loblolly Pine	       5/20/2010	14    	0.61
Carbon	Stand 1	Loblolly Pine	       5/20/2010	16    	0.75
Carbon	Stand 1	Hard Hardwoods	5/20/2010	6	        27.4
Carbon	Stand 1	Hard Hardwoods	5/20/2010	8      	16.4
Carbon	Stand 1	Hard Hardwoods	5/20/2010	10     	16.1
Carbon	Stand 1	Hard Hardwoods	5/20/2010	12    	18.3
Carbon	Stand 1	Hard Hardwoods	5/20/2010	14     	9.9

I want the TreesPerAcre number to be divided evenly (1.2/20) over the
tenth inch DBHClasses.  For example, A 10 inch DBHClass would range
from 9.1 to 11.0, the 12 inch class would be from 11.1 to 13.0, etc.
Any help will be greatly appreciated.

TractID	StandID	Species	CruiseDate	DBHClass	TreesPerAcre
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.1   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.2   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.3   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.4   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.5   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.6   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.7   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.8   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	9.9   	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.0  	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.1 	0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.2	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.3	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.4	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.5	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.6	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.7	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.8	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	10.9	        0.06
Carbon	Stand 1	Loblolly Pine	5/20/2010	11.0	        0.06
etc.

Information:
R  2.11.1
Windows 7

Thanks in advance,

Randy