Hazelnuts, filberts, Corylus avellana

A few years ago a processing plant  for hazelnuts was found on one of  the Scottish islands. It is dated to be  over 9000 years old. Possibly the first factory in human history. In 2009,  773 828 tons were produced worldwide, leaving  a potential consumer with  113.5 grams of  hazelnuts (including the shell weight). That's about 33 hazelnuts, and each has about 8.6 calories-- so its a good snack once a year for everybody.
Biggest producer is Turkey, which traditionally brings 70-80% of  the world crop. In 2009, Turkey produced  500 000 tons of hazelnuts, that's almost 6.9 kg of hazelnuts per capita.

600 530 hectares (100% + increase since 1961) were dedicated to hazelnut production in 2009, a territory similar to occupied Palestinian territories. That is 0.387 % of all permanent crop land in the world.

Assuming 40 % to be  edible  weight , world crop of 2009 could provide about 2.65 million people with 2000 calories a day.
Prices vary and go up consistently:

Turkey has exported 137,774 tonnes of hazelnuts in the first four months of the 2010-2011 export season and earned 805.4 million USD.

According to the Union of Black Sea Hazelnut Exporters, Turkey exported hazelnuts to around 90 countries in all corners of the world between September 1, 2010 and December 31, 2010 and earned 805.4 million USD from the exports. 104,491 tonnes of Turkish hazelnuts went to European Union (EU) countries in the first four months of the export season. Turkey had exported 104,161 tonnes of hazelnuts in the same term last year and had earned 639.2 million USD. List of all articles at Ironrye:  http://ironrye.blogspot.com/2011/10/list-of-all-articles-at-iron-rye.html Land usage, in hectares: Azerbaijan Hazelnuts, with shell 19994 21577 22193 Belarus Hazelnuts, with shell 1000 F 1000 F M Bulgaria Hazelnuts, with shell 702 700 F 700 F Cameroon Hazelnuts, with shell 100 F 100 F M China Hazelnuts, with shell 9000 F 9000 F 10500 F Croatia Hazelnuts, with shell 1246 1877 2000 F Cyprus Hazelnuts, with shell 85 80 71 Denmark Hazelnuts, with shell 6 F 6 F 6 F France Hazelnuts, with shell 2916 3227 M Georgia Hazelnuts, with shell 12000 F 10000 F 12000 F Greece Hazelnuts, with shell 652 650 F 650 F Hungary Hazelnuts, with shell 88 103 99 Iran (Islamic Republic of) Hazelnuts, with shell 19500 F 19500 F M Italy Hazelnuts, with shell 72314 71050 M Kyrgyzstan Hazelnuts, with shell 4500 F 4500 F 4500 F Mongolia Hazelnuts, with shell 300 F 300 F M Poland Hazelnuts, with shell 3100 3131 2663 Portugal Hazelnuts, with shell 500 527 527 Republic of Moldova Hazelnuts, with shell 800 F 800 F M Romania Hazelnuts, with shell 1 5 F 11 * Russian Federation Hazelnuts, with shell 600 F 600 F M Slovenia Hazelnuts, with shell 43 43 52 Spain Hazelnuts, with shell 16802 15411 13500 F Tajikistan Hazelnuts, with shell 800 F 800 F M Tunisia Hazelnuts, with shell 40 F 40 F M Turkey Hazelnuts, with shell 433920 412468 421108 Ukraine Hazelnuts, with shell 30 30 40 United States of America Hazelnuts, with shell 11574 11493 11493 Uzbekistan Hazelnuts, with shell 1000 F 1000 F M World + (Total) Hazelnuts, with shell 613613 A 590018 A 600530 A Production, in tonnes: item 2007 2008 2009 Azerbaijan Hazelnuts, with shell 27462 27745 30430 Belarus Hazelnuts, with shell 1800 F 1800 F M Bulgaria Hazelnuts, with shell 17 20 F 23 Cameroon Hazelnuts, with shell 100 F 100 F M China Hazelnuts, with shell 15000 F 16000 F 18000 F Croatia Hazelnuts, with shell 1240 1289 1384 Cyprus Hazelnuts, with shell 40 38 50 Denmark Hazelnuts, with shell 5 F 5 F 5 F France Hazelnuts, with shell 5371 4999 M Georgia Hazelnuts, with shell 21200 18700 21800 Germany Hazelnuts, with shell M M M Greece Hazelnuts, with shell 1497 1497 F M Hungary Hazelnuts, with shell 79 98 69 Iran (Islamic Republic of) Hazelnuts, with shell 18000 F 18000 F M Italy Hazelnuts, with shell 128231 111841 M Kyrgyzstan Hazelnuts, with shell 3242 3000 F 3000 F Mongolia Hazelnuts, with shell 300 F 300 F M Poland Hazelnuts, with shell 3470 3434 3055 Portugal Hazelnuts, with shell 400 418 438 Republic of Moldova Hazelnuts, with shell 800 F 800 F M Romania Hazelnuts, with shell 3 6 11 Russian Federation Hazelnuts, with shell 800 F 800 F M Slovakia Hazelnuts, with shell 0 0 M Slovenia Hazelnuts, with shell 115 52 236 Spain Hazelnuts, with shell 16134 24000 10500 Tajikistan Hazelnuts, with shell 1000 F 1000 F M Tunisia Hazelnuts, with shell 40 F 40 F M Turkey Hazelnuts, with shell 530000 800791 500000 Ukraine Hazelnuts, with shell 10 20 10 United States of America Hazelnuts, with shell 33568 29030 42640 Uzbekistan Hazelnuts, with shell 1000 F 1000 F M World + (Total) Hazelnuts, with shell 810924 A 1066823 A 773828