Modelling spiral grain angle variation in New Zealand-grown radiata pine

Abstract:With conifer plantations having an increasingly important role in meeting the fiber needs of society, an understanding of the effect of silvicultural practices on wood quality is critical. The perception of wood quality varies, making it hard to define in a single statement; however, possibly the most succinct definition is "a measure of the aptness of wood for a given use". In general, properties that have a positive influence on a specific product assist in defining changes in wood quality. Since wood properties exhibit large variability within annual rings, within trees, and among trees in a stand, and have both genetic and environmental components (i.e., vary with different physiographical regions), it is imperative to have an understanding of wood properties at multiple levels. In this paper, we review the typical variation patterns in wood properties of conifers, with specific emphasis on loblolly pine (Pinus taeda L.), and radiata pine (Pinus radiata D.Don), two of the most common conifer plantation species globally. We also describe the impact of conventional silvicultural treatments on wood quality. Modeling efforts to predict variation in wood properties within trees, and in response to silvicultural treatments are also summarized.

Section: Wood Property Variationmentioning

confidence: 99%

Section: Mathematical Models For Explaining Variation In Wood Propertmentioning

confidence: 99%

Section: Mathematical Models Predicting Silvicultural Responses In Womentioning

confidence: 99%

See 1 more Smart Citation

Wood and Fiber Quality of Plantation-Grown Conifers: A Summary of Research with an Emphasis on Loblolly and Radiata Pine

Schimleck

Antony

Dahlen

et al. 2018

“…• X-ray densitometry to measure specific gravity [18][19][20] • X-ray diffraction to measure the microfibril angle [21][22][23] • Automated image analysis to measure fiber dimensions on macerated fibers [24,25] or on solid wood samples [26][27][28] • Near-infrared spectroscopy to predict a variety of properties [29][30][31] • Acoustics in combination with density to measure stiffness [32,33], or to correlate acoustic velocity values to MFA or tracheid length [34,35] • Light transmission to measure spiral grain [36,37] Of the aforementioned tools, X-ray densitometry has arguably been the most widely used to investigate radial patterns of variation. This is undoubtedly due to the overall importance of wood density, the ease of measurement, and the variety of X-ray densitometry instruments/techniques that are available [20].…”

Section: Introductionmentioning

confidence: 99%

Models for Predicting Specific Gravity and Ring Width for Loblolly Pine from Intensively Managed Plantations, and Implications for Wood Utilization

Dahlen

Auty

Eberhardt

2018

Abstract:Loblolly pine (Pinus taeda L.) is increasingly grown on intensively managed plantations that yield high growth rates. Wood properties, including specific gravity (SG), change with cambial age, and thus intensively managed trees contain a high proportion of low density corewood when harvested because of reduced rotation lengths. This study was undertaken to develop models of ring-level properties (SG and width) in intensively managed loblolly pine plantations. Ninety-three trees from five stands aged from 24 to 33 years were harvested, and 490 disks were obtained from in between the 5.2-m logs that were cut, and at the merchantable top. The disks were cut into pith-to-bark radial strips that were scanned on an X-ray densitometer, and the resultant data analyzed using non-linear mixed-effects models. The fixed effects of the models, which included cambial age and for some models disk height and ring width, were able to explain 56, 46, 54, 16, and 46 percent of the within-tree variation for ring SG, ring width, latewood SG, earlywood SG, and latewood percent, respectively. To assess implications for wood utilization, a modeled tree was built by using height, diameter, and taper equations and these models were linked with the developed ring SG model to produce a tree properties map. The linked information was also used to generate tree and log SG and proportion of corewood values for different rotation ages. The results from this study are a step towards integrating wood quality models into growth-and-yield modeling systems that are important for loblolly pine plantation management.

“…For most wood properties the initial radial progression is steep, followed by asymptotic approaches to outerwood values [11,12]. One exception is spiral grain angle, which typically shows an initial increase before dropping more or less asymptotically [13]. The detailed pith-to-bark trajectories in relation to ring numbers from the pith differ markedly among properties, and for individual properties they can differ appreciably among trees.…”

Section: Introductionmentioning

confidence: 99%

Adverse Genetic Correlations and Impacts of Silviculture Involving Wood Properties: Analysis of Issues for Radiata Pine

Burdon

Moore

2018

Plantation forestry is now an imperative to meet wood requirements efficiently on the finite land available for wood production. Three main determinants of profitability are productivity, price per unit of wood harvested, and harvest age (the sooner the better). The first two are largely self-evident, while reducing harvest age lowers the effective cost of growing wood. Among these determinants, however, are strong interplays which include trade-offs. Key trade-offs involve adverse genetic correlations between various wood properties and growth-rate variables, and adverse effects on the wood quality of silvicultural interventions that raise site productivity and/or reduce harvest age. Moreover, the adverse effects of silviculture on wood properties tend to be accompanied by heightened expressions of genetic variation in wood properties. The trade-offs involve both increasing the percentage of corewood ('juvenile wood') and some more direct effects on wood quality. The pervasiveness of the trade-offs, and the heightened genetic expression, accentuate the call for genetic selection to defend wood quality. Such selection, however, will entail some costs in the appropriate emphasis on breeding for productivity. In this paper we review these issues, identify gaps in research information and offer guidance for tree breeders and silviculturists. While radiata pine is the special case, the applicability to some other species is briefly discussed.