In a note to clients — as reported by “AppleInsider” (www.appleinsider.com) — Needham & Company analyst Charles Wolf — says that market data in the June quarter showed with certainty for the first time ever that the iPad is replacing sales of traditional computers to schools and students.

He says that computer education shipments fell by 265,000 units, or 13.9% from the June quarter a year ago. On the other hand, Apple sold nearly a million iPads in the K-12 market in June, which he said is “definitive evidence” that the iPad has been “cannibalizing” computer sales in the U.S. education market.

However, this cannibalization seems to be mainly affecting the PC market, not Macs. Apple sold four million Macs in its most recent fiscal quarter that ended in June. Apple Chief Financial Officer Peter Oppenheimer said the Mac had its best ever educational quarter. For example, the Rutherford County, NC school system bought 6,000 MacBook Airs, and Pueblo Colorado school district bought 70 MacBook Airs.

“Clearly, a significant portion of iPad sales represented an expansion of the market,” Wolf wrote. “But in view of the fact that Mac sales held steady at around 520,000 units but overall PC sales declined by 265,000 units from 1.90 million to 1.64 million units, we believe the inescapable conclusion is that the iPad is beginning to cannibalize a material portion of PC sales in this market.”