Morphological Crown Attributes Contributing to Differential Height and Diameter Growth among Families in a Coastal Douglas-Fir Progeny Test: Crown Structural Evidence for Crop Ideotypes

Theoretical tree crop ideotypes have long and narrow live crowns with a high total leaf area. This crown form allows more efficient exploitation of site resources, in part by physically occupying less growing space per unit area packing greater number trees into given Genetic selection for has been proposed as strategy maximizing productivity stands managed under intensive silviculture. The primary objective this study was to test the relationship between relative growth performance different families Douglas-fir (Pseudotsuga menziesii var. [Mirb.] Franco) progeny morphological attributes that conform theoretical ideotype. overarching goal identify conferring superior height diameter on facilitate incorporation these associated mechanisms hybrid models intensively plantations. Crown structural were measured destructively sampled averaged entire each third length among families. Multivariate analysis revealed over performed best identifying growth, followed successively bottom, middle, top third. Trees relatively short branch lengths steep angles tended higher (TLACL), attribute showed strong positive correlation cumulative growth. ratio width (CWL) moderately negatively correlated displaying most rapid conformed ideotype, while those displayed obvious ideotype concept. TLACL implied one possible mechanism driving genetic gain families, its heritability strongly performance. Incorporating an explanatory variable could at least partly represent levels. is rate, so incorporating CWL may better effects models.