Walnut trees in Shahmirzad, Semnan province, have been around for 3,000 years and have been named as the region's special tree by Professor German of FAO. The area under walnut cultivation in Semnan is 3,552 hectares, with 52% located in Shahmirzad. The region is known for its native and high-yielding walnut cultivars, including 'Shahmir' and 'Shahmir' and other varieties like almond, hazelnut, paper and needle, Franket, and Farnour.