Field Notes from the Food Intensive: Wolfskill Experimental Orchard

Heather Sieger, Student
Wednesday, September 24, 2014
On Monday, our second stop was at Wolfskill Experimental Orchard, or National Clonal Germplasm Repository, which is owned by the federal government and land is leased from UC Davis. I enjoyed seeing this “living library” of so many different species and varieties of fruits and nuts. First, we learned all about how grafting works. Grafting means to take a limb off of one tree and line it up with a similar part of another tree and since trees’ immune systems are so much different from our own, it heals up the cut and the new branch will grow into the tree. It was common here to see walnut trees with the bottom of their trunks a darker bark color than the top because of the types of trees grafted onto one another. The darker color is a type of walnut that has a strong root system that fights off bacteria and diseases, which the top kind is another variety that we want. I find this interesting because you could have so many different varieties of a fruit on one single tree, and for apples, all of each variety comes from one tree and then is grafted onto other apple trees.
Since this is a Germplasm Repository, they do not harvest the food grown here and just keep it as a place to preserve species and varieties of grapes and fruit trees and nuts. I was impressed with all of the grapes—there are 3500 varieties at this orchard, some with seeds and some without. How are seedless grapes grown? They actually have seeds when they are young, but at a certain time as they are maturing they get a mutation that kills them. In order for these to reproduce from seed, someone must go into the grape as it is young and take out the premature seeds before they leave.
We also got to see and taste olives, pistachios, and figs. Olives taste really bad when they are first picked off of a tree, they are very bitter and need to go through much processing to taste how we are used to them tasting. To make olive oil, the olives are juiced and then the oil and water that comes out is separated because the water holds the bitter taste while the oil is what we know. The pistachios have three layers, the seed, the shell, and an outer coating. Unique about this nut is that the shell forms before the seed inside forms, which is opposite than must nuts like almonds and walnuts. The figs were different colors, so that wasn’t what told us they were ready to be eaten, but rather when their stems were leaning downwards. I really enjoyed spending time at and learning about the Wolfskill Orchard!

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