<http://webisa.webdatacommons.org/273972541>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/273972541>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<fs.fed.us> .
<http://webisa.webdatacommons.org/prov/318273964>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/273972541> .
<http://webisa.webdatacommons.org/273972541>	<http://www.w3.org/ns/prov#value>	"Previous work by this Research Work Unit has shown that both acidic deposition and timber harvesting contribute to removal of base cations, such as potassium, magnesium, and especially calcium, from forest ecosystems." .