I've seen them look more sparse sometimes around here when they're grown too far inland and have to deal with too much summer heat. I'm not sure what the summers are like in that part of NZ but that would be a possibility.
Our winters are very mild in comparison to your part of the world ... -6 degrees at coldest in Hamilton, and definitely no snow in this part of the North Island of NZ where this photo was taken. Sorry, growin, we can't produce them like you do over there!!
Thank you all for your interest and great knowledge.