Patterns between crown characteristics and radial increment in trees are similar during recovery and normal growth: a long-term example from old-growth forests

Crown traits and competition attributes have an important effect on tree radial increment. Relationships among these elements are modeled using the distributions of the crown characteristics in a given calendar year, but these patterns can differ through time. The suitability of the patterns during recovery and normal growth was investigated with the example of the fir Abies alba Mill. in old-growth forests. Generalized additive models (GAMs) for fir in the older (OG, trees aged 136 to 300 years) and younger (YG, trees aged 45 to 135 years) generations were developed. To test the validity of these GAMs, field data sets representing fir recovery and normal growth were used. In the case of fir in OG, crown transparency had the largest effect, explaining more than 25% of the variance. For fir in YG, relative crown length had the largest effect on tree growth, explaining more than 15% of the variance. The absolute relative prediction errors, AREmin and AREmax, were less than 0.03 and 1.50 mm, respectively. The developed GAMs are suitable during recovery and normal growth, but the GAMs were fitted to a relatively small area which neglects climatic gradients and different disturbance types; this type of investigation should be continued.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author