That is why Hisøya today stands out among the grey rock-faced and moor-covered islands of the northeastern part of Bømlo municipality.
With his own studies of forest culture as ballast and The Norwegian Forest Company as his partner, Heitmann started planting forests in 1895. In the poorest growing areas he planted bush pine and mountain pine. In the valleys, where there was better growing conditions, he tried planting common pine and spruce, various species of silver fir, Sitka spruce and several species of deciduous trees. Heitmann set also about with clearing and digging drainage, and after he died, his heirs continued his work.
After a while, it appeared that the scepticism was warranted, because several of the tree types grew poorly. It was advised that it would be most prudent to plant the rest of the island with the hardier bush pine But, at least Heitmann managed to prove that forest could in fact grow so far out in the sea.
When His Majesty King Haakon VII celebrated Christmas in England in 1942, the Christmas tree was silver fir from Hisøya. Helped by good local knowledge of the area, folk on board the Shetlands Larsen sailed in to the island to collect the Christmas tree. The tree was cut at about 1 metre height, with the result that a branch turned upwards again and since has become another big tree. It now goes by the name "King Pine"