However to the east of Taupo the barren, ash-laden soils and harsh alpine climate leave the high land largely bare and unprofitable, capable of growing only scrubby plants. This area is known as the Rangipo Desert although it is not a true desert as the annual rainfall is over 1,000mm PA and the real reason for the low and sparse vegetation was the mass sterilization of seeds caused by the 20,000-year-old Taupo eruption, which swept white-hot ignimbrite through this valley. Prior to this cataclysmic event this area was forested and stumps of charcoalized trees can be seen where soil has eroded.