Old Tjikko, Norway spruce in Fulufjället National Park, Älvdalen Municipality, Sweden

Old Tjikko is a Norway spruce located in Fulufjället National Park within Älvdalen Municipality in central Sweden. The tree rises roughly 5 meters high on a mountain summit and displays multiple trunks shaped by wind and cold conditions.

Old Tjikko is a clonal Norway spruce whose root system was radiocarbon-dated to 9,550 years, with root samples of 375, 5,660, 9,000 and 9,550 years found beneath it. Leif Kullman of Umeå University and Lisa Öberg discovered the tree and named it after their late dog Tjikko. It grew as a stunted krummholz shrub until 20th-century warming let it take normal tree form.

The tree is named after Tjikko, the late dog of Lisa Öberg, who found it together with Leif Kullman of Umeå University; the German source credits the naming to Öberg. Around twenty other spruces in the same area are also over eight thousand years old, and in 2024 twigs from Old Tjikko's top branches were grafted onto other spruces for a climate-controlled installation in Malmö.

Old Tjikko stands on Fulufjället Mountain in Fulufjället National Park, Älvdalen Municipality, about five kilometres east of the Norwegian border. The site lies on rocky, moss-covered ground, and a thin white rope strung on short posts passes in front of the tree. Nature conservancy authorities considered fencing the tree to protect it from vandals and trophy hunters.

The spruce survived thousands of years as a low shrub formation called krummholz before developing into its current tree form due to climate changes. This adaptability shows how plants can respond to shifting environmental conditions without abandoning their root system.