200 ppm

The plastic house is not used in winter. It shows end venting. Located at Haapastensyrja

Rooted cuttings of PIa in heated peat at Haapastensyrja

Niels Kreiberg standing next to 5 yr Populus tremula × Populus tremuloides in Haapastensyrja

Pinus sylvestris in Nisula Roll located at Haapastensyrja

The image shows grafts used for tree breeding in Haapastensyrja

PIa sown May/70 in plastic house at Haapastensyrja

PIa was sown May 9/70 in peat which later will be lifted and
stored at -5 C in fall (Sept./70). Initially planted in a temporary plastic house in Haapastensyrja.

PIa was sown May 9/70 in peat which later will be lifted and stored at -5 C in fall (Sept./70). Initially stored at a temporary plastic house in Haapastensyrja

Pinus sylvestris sown March 1969 and transplanted
into Nisula beds 1970 at Haapastensyrja.