Just got back from a 2 week trip to New Zealand - it's been my #1 "bucket list" place for a long time. I was especially excited to see trees that are San Francisco street trees (New Zealand Christmas trees, giant dracaena, tea trees, etc.) in their native habitat.
One thing I noticed was LOTS of Monterey cypress (Cupressus macrocarpa) and Monterey pine (Pinus radiata, which the New Zealanders call "Radiata pine") in the countryside, used as windbreaks, shade for sheep and other livestock, accent trees, etc. Which made big parts of the countryside look a lot like California! There were also many stands of Monterey pine used used as lumber trees - without any evidence of pine canker that i could see.
Northern hemisphere conifers (Douglas fir is a prominent example) have become naturalized in big parts of New Zealand, and have become invasive pests, taking over entire landscapes. Interestingly, our Monterey pine and Monterey cypress are not invasive, because the cones of the tree typically only open and disburse their seeds where there is fire or extremely hot weather.
I spent three days hiking through native beech forest on the Routeburn Track on the South Island. It was very cool to see forests composed almost entirely of different species of Nothofagus (a cousin of our northern hemisphere beeches) because they were so new to me (the only Nothofagus I can remember seeing here in CA was a giant specimen at Filoli, south of San Francisco). One cool tree I encountered along the way: the tree fuchsia - Fuchsia excorticata, the world's largest fuchsia, with distinctive papery bark (and recognizable fuchsia flowers).
Of course, I made a point to find New Zealand Christmas trees (Metrosideros excelsa) on the North Island, although sadly by the time we got there on January 2, they were almost all out of bloom (these native trees seemed to be strict about blooming at Christmas time). They're called by the Mauri name "Pohutukawa" in New Zealand, and the New Zealanders were very surprised to find that they were popular street trees in San Francisco.
Sadly we didn’t get to see any Nikau palms (New Zealand's only native palm, and one of my favorites of the palms) in their glory - saw a few of them planted as street trees (!) in Whangarei in the north island, and every once in a while saw one in the kauri forest on the west side of the north island. I was surprised to find that the best places to see them in New Zealand were on the west side of the cooler south island.
It was a great trip - New Zealand is a great place to visit for many reasons, and interesting trees is definitely one of them!