The effects of pre-commercial thinning and fertilization on characteristics of juvenile clearwood of Scots pine (Pinus sylvestris L.)

As a result of escalating demands for wood and parts of trees for use as biofuels and energy generation, there is growing interest in increasing forest biomass production. The objective of this study, therefore, was to investigate whether the physical properties and modulus of elasticity (MOE) of Scots pine (Pinus sylvestris L.) juvenile clearwood change in response to different silvicultural treatments (pre-commercial thinning and fertilizer application) in 22- to 25-year-old trees. We achieved this by measuring short-term mechanical properties and using X-ray densitometry. The results show that the MOE and latewood density were not affected by any treatment. The earlywood density and the percentages of earlywood and latewood were affected by the treatments. Fertilization increased ring width and the percentage of earlywood but decreased the percentage of latewood. Pre-commercial thinning also increased ring width and the percentage of earlywood, and decreased the percentage of latewood, but did not affect earlywood density. Furthermore, our results suggest that the MOE of wood is not affected by the different treatments as long as the cambial age and ring width are the same and that fertilization should be considered as a factor that increases the site index where intra-ring properties are concerned.