A novel approach for the operational production of hybrid larch seeds under northern climatic conditions

Hybrid larch ([Larix × marschlinsii Coaz], HL) is sought after by the forest industry because of its growth characteristics, excellent wood quality and disease resistance. However, the difficulty in obtaining HL seeds limits the production of seedlings for reforestation. Both European larch (Larix decidua Mill.) and Japanese larch (Larix kaempferi [Lamb.] Carriere) produce few seeds and the time lag in their flowering phenology complicates their natural pollination. We have developed a novel type of sheltered seed orchard, dedicated to the production of HL seeds from grafts grown in pots. Inverting the arches of a conventional tunnel provides a sturdy structure which is easy to maintain. Because of its height, the tunnel can accommodate the rapid growth of the trees, which reduces the need for pruning. The tunnels are covered in the winter and spring. In the winter, the covers prevent snow accumulation. In the spring, they create a "greenhouse effect" inside the tunnels, accelerating flower development, p...