"Nó de Pinho" ( stands for"Araucaria-Pinetree-Knots" )   as the most excelent natural firewood, is found so far, exclusively in Brazil.  They are normally sold in 10 Kg - 15 kg bags.  . The "knots", heavy pieces of "resin-impregnated-conic-shaped-wood", during many centuries resisted decay under the soil, long after the large stems (which originated them), were naturally decomposed.  These KNOTS (intersection of branches to their stems) remained unchanged on the graund. Actually can solely be disintegrated by fire. Their sizes vary. any of them big or small, burn excelently. .                                                                              B A C K    Their flame last for hours.  Wise users, save the precious knots    mixing them up with Eucalyptus or Pinetree-firewood.

Origin: During centuries those huge Araucaria-trunks kept falling to the ground, eventually struck by lightning, fires  etc.  (one may say also through "aging" - end of life cycle)
 Nowadays, while plowing, farmers finding them under the ground, collect the knots, pile them up, thus providing an "additional income",  selling them as fire-wood. 
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Since thousands of years the Brazilian South East coast was covered by the "Atlantic Forest"
( Brazilian designation for Native forests along the Atlantic ).  Particularly in the brazilian Southern States: Paraná, Santa Catarina, Rio Grande do Sul, Sao Paulo and Minas Gerais, the dominant specie was the ARAUCARIA, designated "Pinheiro do Paraná" - araucaria angustifolia and araucaria brasiliensis. 

. These trees in the past reached up to 52 meters height and their trunk up to 8,5 meters circumference. The cones are shaped like a ball with over 30 cm diameter and provide seeds averaging  6 cm length. (These are edible ! Boiled, some butter and salt added, are a real delicious 'TREAT').