Walker was asked why he selected oaks as a central design element. He said he specified white oak, ?EUR??,,????'??essential swamp oak?EUR??,,????'?? and sweet gums (liquidambars) to line the great lawn, because N.Y. City is very strict on what trees can be planted. The city recommends only six or seven trees and the sweet gums and white oak are on the list.

When would the memorial be ready? Sept. 11, 2009, he replied.

Special problems? There was essentially no ground soil for planting trees, so soil had to be imported throughout the site to a depth of six feet, which will allow the trees to grow for 50-100 years. He noted the average N.Y.C. tree live about seven years.

The cyber chatters learned that dogs, Frisbee play and touch football would not be allowed on the park site.

?EUR??,,????'??For God sakes, what is wrong with dogs??EUR??,,????'?? wrote delajjo, a distraught participant.

Walker: ?EUR??,,????'??We are very conscious of the respect required for the memorial.?EUR??,,????'??

Chatter site_313 asked an interesting technical question: ?EUR??,,????'??I am curious how you will overcome air currents, updrafts and wind effects on the free-falling water, especially in the slotted area at the mid-level??EUR??,,????'??

Walker: We have had a number of wind tunnel tests made?EUR??,,????'???The mock-up of the waterfall was reviewed for winds within the memorial and the design has reflected all of this information.?EUR??,,????'??