Age and weather effects on between and within ring variations of number, width and coarseness of tracheids and radial growth of young Norway spruce

Abstract

Annual growth, fibre and wood properties of Norway spruce are all under strong influence from genetics, age and weather. They change dynamically, particularly at young ages. Most genetic research and tree improvement programs are based on data from this most dynamic phase of the life of trees, affected by differences in weather among sites and years. In the work presented, influences of age and weather were investigated and modelled at the detail of annual rings and at the sub-tree ring level of earlywood, transitionwood and latewood. The data used were analysed from increment cores sampled at age 21 years from almost 6000 Norway spruce trees of known genetic origin, grown on two sites in southern Sweden. The traits under investigation were radial growth, cell widths, cell numbers, cell wall thickness and coarseness as a measure of biomass allocation at cell level. General additive mixed models (GAMMs) were fitted to model the influences of age, local temperature and precipitation. The best models were obtained for number of tracheids formed per year, ring width, average radial tracheid width in earlywood, and ring averages for tangential tracheid width and coarseness. Considering the many sources behind the huge variation, the explained part of the variability was high. For all traits, models were developed using both total tree age and cambial age (ring number) to express age. Comparisons indicate that the number of cell divisions and ring width are under stronger control of tree age, but the other traits under stronger control of cambial age. The models provide a basis to refine data prior to genetic evaluations by compensating for estimated differences between sites and years related to age and weather rather than genetics. Other expected applications are to predict performance of genotypes in relation to site or climate and simulation of climate change scenarios.

Genome‐wide association study identified novel candidate loci affecting wood formation in Norway spruce

“…These included the identification and dating of all annual rings and their compartments of early wood (EW), transition wood (TW) and late wood (LW). For this, a density-based '20-80' definition was used, described and discussed in (Lundqvist et al, 2018). Traits of interest to breeders were derived from the SilviScan data, such as the radial NC and Mass Index (MI) introduced to express the relative amount of biomass at breast height.…”

The effect of tree (and cambium) age on genomic prediction for solid wood properties in Norway spruce

“…For wood density, the results indicate that models can be built without coring very deep into the stem. It may be expected that this is valid also for instance for tracheid dimensions which in combination determines the wood density 34 .…”

“…This data is referred as increment core-based measurements through the text. The annual rings of all samples were identified, as well as their parts of earlywood, transition wood and latewood, averages were calculated for all rings and their parts and dated with year of wood formation 34 .…”

Effect of number of annual rings and tree ages on genomic predictive ability for solid wood properties of Norway spruce

“…This data is referred as increment core-based measurements through the text. The annual rings of all samples were identified, as well as their parts of earlywood, transition wood and latewood, averages were calculated for all rings, as well as their parts and dated with year of wood formation 33 .…”