In Iceland, these green houses melt into the natural landscape, a technique that first appeared with the arrival of British settlers during the 9th through 11th centuries. Unlike their previous warm and wet climate, wood was rare and slow to regenerate. Turf (草皮) became their first pick to make shelters.
Across Europe, turf bricks — widely available — were cut from local bogs (沼泽) and transported for use at higher lands. The turf was then laid over a wooden structure to form walls and a thick roof — to keep cold out from tough northern climates. Turf walls were replaced as frequently as every 20 years, and even up to 70 years.
It is difficult to find out its precise origins in the archaeological record. However, evidence of similar constructions can be found in many countries throughout the ages. Historic records suggest that up to 50 percent of Icelandic houses were partly comprised of turf until the late 19th century. As populations began to gather in cities like Reykjavik, wood buildings replaced stones and earth architecture. After fires burned up the city in 1915, concrete became the material of choice. In 1918 Iceland gained independence from Denmark, setting in motion a wave of nationalism that threatened the survival of turf houses. Advocates of modernization argued that Reykjavik paled in comparison to the grand architecture that graced the skylines of Paris, Berlin, and London. Traditional techniques were criticized as "rotten Danish wood" from a troubled era, and there was a campaign to clear them in favor of modern buildings — a move later criticized by many as destruction of cultural heritage.
A tourism boom in the latter half of the 20th century encouraged Iceland to reexamine the value of traditional architecture. Do Icelanders still live in turf houses? The quickest way to answer this question would be no. You might still see an occasional grass roof but that has everything to do with architecture and Icelanders wanting to hold on to their beloved heritage rather than any need for turf as insulation (隔热) material.