Scandinavian roots of the poplar breeding program at Geraardsbergen

From the mid 1920's K.E. Hedborg was in contact with Swedish foresters. Match factories of the S.T.A.B. group in Sweden used aspen (Populus tremula), mainly from local origin or from the Baltic States. Factories in Belgium traditionally used aspen they imported from the USSR, or wood from local poplars (P. deltoides x P. nigra).

A. Quairière reported in 1936, after a visit to the Sveriges utsädesförening at Svälov (Sweden), the finding (1935) by Nilsson-Ehle of triploid Populus tremula gigas.

Hermann Nilsson-Ehle was the driving force behind the founding of "Föreningen för Vaxtförädling av Skogsträd" by the private sector at Ekebo, with its first director N. Sylvén. S.T.A.B. (the swedish group to which Unal belonged) was one of the founding companies putting money in Ekebo. In 1938 (or 1939) Nilsson Ehle visited Union Allumettière at Geraardsbergen. He became for years an adviser for Unal.

Helge Johnson, at that time assistant at Ekebo, also found several triploid Populus tremula. In 1939 he made the first, also fast breeding, crossings between Populus tremuloides x Populus tremula.











In 1940 S.T.A.B., convinced by their timber expert Stig Wijkström, bought some land at Mykinge where the Ekebo Research institute established research plots over 40 ha with both triploid and hybrid aspen. After World War II it was no longer possible to import wood from the Baltic. All aspen timber had to be purchased within Sweden. About 1950, with increasing demand after wood, S.T.A.B. decided to produce plants of hybrid aspen at Mykinge and sell them to forest owners. Between 1951 and 1968 about 700.000-800.000 plants have been produced. However many plantations have to a great extend failed, primarily because of damages by wild animals (moose).

Due to a decreasing demand for wood, it was decided in 1967 to stop the plant production at Mykinge, and to transfer it to Hellestrup Planteskole (property since 1942 of S.T.A.B.) in Denmark, where allready for years F1 hybrids between Populus tremula and Populus tremuloides were produced at a very large scale. Selling of plants varied between 100.000 and 150.000 plants per annum. This work was inspired by Dr. Syrach Larsen at the National Arboretum at Hørsholm who made his first interspecific aspen hybrids in 1942.

Beside this work on aspen, Helge Johnson commissioned by S.T.A.B., travelled in 1947 through Canada and the U.S.A., accompanied by Scott Pauley, and selected together many plus-trees of P. deltoides, P. trichocarpa, P. tacamahaca, P. grandidentata and P. termuloides. Spring 1948 Helge Johnson returned to the same area and came back to Geraardsbergen with flowering twigs of these plus trees.

The technician Jean Quintelier made the first full-sib crosses. All these high-valued clones were also vegetatively propagated (grafted) and became an important base collection for the later breeding program at Geraardsbergen.