Shoot growth processes, assessed by bud development types, reflect Norway spruce vitality and sink prioritization

• Published in: Forest ecology and management 2006-04, Vol.225 (1), p.337-348
• Main Authors: Polák, Tomás, Rock, Barrett N., Campbell, Petya Entcheva, Soukupová, Jitka, Solcová, Blanka, Zvára, Karel, Albrechtová, Jana
• Format: Article
• Language: English
• Subjects: air pollution; assimilate allocation; Buds; carbon; Carbon allocation; chemical composition; chlorophyll; conifer needles; conifers; Crown defoliation; defoliation; forest health; forest trees; Krusne hory mountains; lignin; Norway spruce ( Picea abies); phenolic compounds; Picea abies; population dynamics; seed cones; seeds; shoots; Sink/source concept; source-sink dynamics; tree crown; tree growth; Tree vitality
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2006.01.027

Crown defoliation, is a product of the tree crown status from the past several years of growth, which can be misleading if used as a stress indicator when assessing current Norway spruce vitality. To evaluate recovery processes in previously damaged trees a newly developed macroscopic indicator based on proportions of bud development types was investigated. In 1998 and 1999, 474 mature Norway spruce trees were sampled for macroscopic measurements, 293 trees for tree-ring increments and 40 trees for study of metabolic markers (concentration of chlorophylls, phenolic compounds and lignin). Study sites were located in the Czech Republic, in the Sumava Mts, a relatively unpolluted and undisturbed area, and in the Krusne hory Mts, which exhibited a whole range of tree damage corresponding to a gradient of increasing air pollution load. Three categories of trees were identified which reflect current levels of intensity of shoot formation and capacity to replace potential needle loss by activation of buds with growth potential: accelerated, stabilized and decreased shoot growth. Relative to sink prioritization, we concluded that the highest vitality occurred in trees with stabilized shoot growth and the lowest vitality in trees with accelerated shoot growth. In conifers, the amount of allocated assimilates to low priority carbon sinks (such as stem growth, production of protective chemical compounds and reproductive organs) depends on what is remaining from the shoot growth processes which are of the highest priority. Significant inverse relationships were found between the intensity of shoot growth, tree-ring increments, production of reproductive organs and concentration of phenolic compounds in the needles. The highest allocation of assimilates to crown recovery occurred in trees with crown defoliation of 50–69% indicating forest recovery was observed in the most heavily damaged areas impacted by air pollution in the past. The present criterion of bud development types has potential for forestry management applications as it is easily applied in the field and, in contrast with standard forestry measurement of crown defoliation, it reflects accurately tree recovery and decline processes under multiple stress impacts.