Predicting Vertical Heartwood Diameter Profiles of Scots pine (Pinus sylvestris L.) Based on Data from the Forest

Concern about environmental impacts of chemical wood preservatives has resulted in increased interest for natural wood durability. The natural durability of sapwood of most species is generally low, while heartwood can be more resistant to biodeterioration. For the sawmill industry various lumber products require certain diameters and lengths of the logs in addition to requirements for wood properties. When utilising the heartwood, it is therefore important to acquire information already in the forest about which trees that can be suitable for logs with a predefined heartwood diameter and length. The main objectives of this work was to study the variation in heartwood diameter along the stem of Scots pines (Pinus sylvestris L.), and to develop a model for predicting heartwood diameter profiles based on variables that can easily be measured in the forest. Variation in heartwood diameter along the stem was studied in 56 Scots pines sampled from northern parts of Norway. Heartwood diameter decreased from the base and upwards the stem in 49 of the trees. Seven trees deviated from this general pattern. In these trees the heartwood diameter increased from the base of the stem to a maximum at approximately 1-3 m, and then decreased towards the top. The model developed for predicting heartwood diameter profiles described 86 % of the variation of heartwood diameter. The model was based on the diameter of the actual cross section as the only input variable. This variable can be acquired by a harvester during logging or during field inventories performed by terrestrial laser scanning