A special thank you to Dr. Sherri Mason, and the Behrend Arboretum!

• Dr. Sherri Mason
• The Behrend Arboretum

Articles:

• Articles about the Arboretum

Various tree information sources:

• BGCI Global Tree Search
• Trees and Shrubs Online
• Botanic Gardens Conservation International
• Nature Serve Explorer
• Arbor Day Foundation
• Nature's Notebook

Tree map and map images:

• Google