The City of Amsterdam maintains 270,000 trees. You can find the location of each one of them, along with their size, stage of life, and age on a website that the city maintains.  Because of that, I know that this photo shows the seedpod from a corylus colurna. It stands in front of 11 Nicolas Maesstraat and was planted in 1956.  You can eat the seeds; they are hazelnuts. In Dutch it is named a boomhazelaar.  You can learn more about the tree on Wikipedia by searching the Latin name. 

Boomhazelaar 2

Also, did you know that the tiny country of the Netherlands is the world's second largest exporter of agricultural products.  They have been very resourceful. They have one of the highest per capita incomes in the world.  Apparently having a high tax rate does not equate with unproductive economies. And everyone has health insurance for reasonable prices.  And people are free to live however they like. Almost the entire population speaks more than one language.  I think the US could learn something from the Netherlands.