15 research outputs found

    Non-destructive assessment of green density and moisture condition in plantation-grown radiata pine (Pinus radiata D. Don.) by increment core measurements

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    A novel protocol for non-destructive assessment of green density and moisture content via increment cores was validated for young (8–10 years) and mature trees (36 years) of radiata pine (Pinus radiata D. Don.). Initial procedures involved comparing 5- and 12-mm cores with fresh disks taken from young trees at breast height and felled during the winter, as well as methods for rehydrating the wood cores. Subsequently, the best method (12-mm cores) was validated with material collected in summer from both young and mature trees. The protocols developed require separate processing of sapwood and heartwood, and soaking the sapwood for 24 h to replace the moisture lost while coring. For young trees, bark-to-pith 12-mm cores accounted for between 64% and 66% of variation in green density of sapwood and between 51% and 72% of saturation percentage, as measured by destructively sampled disks. For mature trees, the average of two sides of 12-mm bark-to-bark cores accounted for 73% of variation in green density of sapwood, and 56% of saturation percentage as measured by destructive wedges. One or both sides of a bark-to-bark core accounted for between 72% and 80% of variation in whole-section green density, and between 70% and 79% of variation in sapwood percentage. The number of heartwood rings was better predicted from the average of two sides of the cores (R2 of 0.71). Whole-tree values (lower two logs) for sapwood green density and saturation were better predicted from the average of both sides of the bark-to-bark core (R2 of 0.76 and 0.57, respectively). Whole-tree values for whole-section green density could be predicted either by one side or two sides of the cores (R2 for 1 or 2 sides of 0.77 and 0.81). Finally, whole-tree sapwood volumetric percent was better predicted by the average of two sides of the cores (R2 of 0.81)

    Can wood density be efficiently selected at early stage in maritime pine (Pinus pinaster Ait.)?

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    La croissance et la rectitude du tronc sont les deux principaux critères de sélection dans le programme d'amélioration génétique du pin maritime en France. Cette étude a pour objectif d'évaluer la possibilité de sélectionner la densité du bois au stade juvénile. Plus de 1 900 arbres, provenant de trois tests, ont été analysés par microdensitométrie. Des gains génétiques relatifs élevés ont été mis en évidence pour la densité du bois au stade adulte (3 à 9 %). Les estimations de la densité réalisées aux stades adulte et juvénile étant bien corrélées, l'efficacité relative de la sélection atteint environ 80 % à l'âge de 12 ans. Les mesures de densité par rayons X ne sont pas envisageables à grande échelle dans le cadre d'un programme d'amélioration, ainsi nous avons évalué l'efficacité de l'utilisation du Résistographe, une méthode indirecte pour estimer la densité du bois sur arbres debout. Des corrélations élevées ont été mises en évidence entre les données obtenues avec le Résistographe et celles obtenues par microdensitométrie (R2 = 0.93 avec les données familiales). Il semble donc possible d'intégrer la densité du bois, estimée avec le Résistographe, comme nouveau critère de sélection dans notre programme d'amélioration.Growth and stem straightness are the two main selection criteria in the French maritime pine breeding programme. In this contribution, our objective was to study the possibility of selecting for wood density assessed at an early stage. We measured X-ray wood density, in three progeny tests, on more than 1 900 breast high increment cores. High relative expected genetic gain (from 3 to 9%) was found for wood density at mature stage. Juvenile and adult wood density estimations were well-correlated; the relative efficiency of early selection reached about 80% at 12 years old. As it would not be realistic to use the X-ray densitometer at an operational scale in a breeding programme, we tested the efficiency of using the Resistograph, an indirect method to assess wood density on live trees. High correlation between the Resistograph and density data (R2 = 0.93 on familial data) was found, suggesting that wood density through Resistograph assessment could be soon integrated as a new selection criterion in our breeding programme
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