The man fatally shot by police at the Hoyt Arboretum on Monday has been identified. From the Portland Police press release:
The man shot on Monday, March 22, 2010, at Hoyt Arboretum has been identified as 58-year-old Jack Dale Collins. He also used the first name of Jackie.

As usual, no further information is available at this time, but we'll be working on bringing you further details later in the morning.
Update! The O reports that "Collins was arrested by Portland police on May 26, 2009 for an unlawful act in a downtown park. At the time, he gave authorities a fictional residential address on East Burnside."