Thursday, October 30, 2008

A Present-Day Gondwanaland Forest

I am using today's post as a bridge back to my continuing story of the real Jurassic Parks (and Cretaceous Parks) on the Colorado Plateau in the southwestern United States. But those parks are in mostly desert environments today, and it can sometimes take a lot of imagination to see the tropical forests that existed in the region during Jurassic or Cretaceous time (of course, imagination is not a bad thing). On the other hand, there is a place in the world that has been detached from any other continent for more than 80 million years, thus preserving some elements of the Mesozoic ecosystems that existed at the time. There was a lot more to see just an achingly short time in the past, only a few hundred years ago.
I am speaking of New Zealand, land of kiwis and hobbits (thank you Peter Jackson, I enjoyed the movies a lot)

New Zealand consists mainly of two major islands, divided from each other across the narrow Cook Strait. The North Island includes Auckland, a city built on dozens of volcanoes, Rotorua, a geyser wonderland sitting in the midst of a huge caldera complex, and the big active volcanoes including Ruapahu, Ngauruhoe and Tongariro. The South Island includes the city of Christchurch, and a series of spectacular mountain ranges including the Southern Alps (remember the spectacular opening sequence of "The Two Towers"?), and the Kaikoura Range that drops 9,000 feet right into the Pacific Ocean (sort of like Big Sur, but three times higher).

Because the island mass separated from other continents prior to the mass extinctions of the late Cretaceous, mammals were present, but never evolved to dominate the ecosystems as they did elsewhere in the world, and eventually went extinct, except for some bat species. With the loss of the dinosaurs, the only vertebrates in position to take over the terrestrial habitat were the birds. With no reptilian or mammalian predators, the birds were able to evolve a flightless existence (flight is an expensive energy proposition if it is not necessary for survival). Eventually a number of very large birds evolved, including ten species of moas. The largest stood over 9 feet tall. They were mainly plant-eaters, but an extremely large eagle lived on the island as the top predator.

Unfortunately, the arrival of humans on the islands around 700 years ago spelled doom for the moas, and when they were gone the large raptors lost a main food source and went extinct as well. Only the kiwi, the small forest dwelling bird, survives today.

The trees on the island provide the other link to the past. I have included some of the huge tree ferns that evoke Jurassic forests in the pictures above (the moas aren't real. Really). The ferns in the third photo line the opening of a 75-foot deep explosion pit at Orakei Korako Geothermal Area on the North Island. I really would not have been surprised if we had been attacked by a few velociraptors in the forest there...

The ancient tree that captured my imagination the most was the Kauri tree (second photo), one of the bulkiest trees on the planet, rivaling even the Sequoia trees in my own backyard of the Sierra Nevada. The most mature trees are not quite 200 feet high, but their trunks remain thick practically to the crown. Their history extends back into Jurassic time. They once covered much of the islands, but unfortunately their wood is strong, mostly knot-free, and attractive. Something like 95% of the original forests have been cut down, and old-growth forests are exceedingly rare and precious. The trees are now protected by law, but ironically, dead trees in swamps are not, and the wood is durable enough that some of the trees from the swamps are still utilized legally, despite having been dead for hudreds or thousands of years.

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