How structural diversity affects Norway spruce crown characteristics

To establish the most important Norway spruce Romanian populations, open-pollinated progeny of ten plus trees originating from 33 seed stands mapped in the Romanian Carpathians have been evaluated for stem and crown characteristics at the age of 30 years, in two field trials: one established in their natural range (BreÅ£cu trial), while the second was located outside of their natural range, in Subcarpathian lands (Avrig trial). Significant (p < 0.05) differences were found among the seed stands in both sites for most of the characteristics, suggesting an additive genetic control with different levels of significance depending on the evaluated trait and the testing site. Location analysis also revealed a highly significant population x locality interaction for all traits. The same populations behave differently to the change of the ecological conditions. In the Avrig trial higher values were recorded than in the BreÅ£cu trial for the tree slenderness coefficient (19%), crown slenderness coefficient (13.6%) and crown lateral area (9.4%). Although outside of their natural area, pruning height (m) increased 6.4%, however pruning height ratio (%) decreases by 1%, compared to the test established in their natural range. The populations from the Eastern Carpathians stand out by showing sustained growth and superior wood quality, while the populations from the Western Romanian Carpathians have generally smaller differences between the mean values of analysed traits in both field trials. Qualitative characteristics that influence the stability of stands to windthrow and snowbreak showed low levels of correlations to ecological gradients of the originating location of tested seed stands.

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Evaluation of stand-level hybrid PipeQual model with permanent sample plot data of Norway spruce

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0236 ◽

2017 ◽

Vol 47 (2) ◽

pp. 234-245 ◽

Cited By ~ 4

Author(s):

Tuomo Kalliokoski ◽

Harri Mäkinen ◽

Tapio Linkosalo ◽

Annikki Mäkelä

Keyword(s):

Norway Spruce ◽

Basal Area ◽

Forest Growth ◽

Stem Volume ◽

Permanent Sample Plots ◽

Crown Structure ◽

Permanent Sample Plot ◽

Crown Characteristics ◽

Linear Regressions ◽

Process Based Models

The evaluation of process-based models (PBM) includes ascertaining their ability to produce results consistent with forest growth in the past. In this study, we parameterized and evaluated the hybrid model PipeQual with datasets containing traditional mensuration variables collected from permanent sample plots (PSP) of even-aged Norway spruce (Picea abies (L.) Karst.) stands in Finland. To initialize the model in the middle of stand development and reproduce observed changes in Norway spruce crown structure, the built-in empirical relationships of crown characteristics were made explicitly dependent on the light environment. After these modifications, the model accuracy at the whole dataset level was high, with slope values of linear regressions between the observations and simulations ranging from 0.77 to 0.99 depending on the variable. The average bias ranged between −0.72 and 0.07 m in stand dominant height, –0.68 and 0.57 cm in stand mean diameter, –2.62 and 1.92 m2 in stand basal area, and 20 and 29 m3 in stand total stem volume. Stand dynamics after thinning also followed reasonable closely the observed patterns. Accurate predictions illustrate the potential of the model for predicting forest stand growth and forest management effects in changing environmental conditions.

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Structural diversity change and regeneration processes of the Norway spruce natural forest in Babia hora NNR in relation to altitude

Journal of Forest Science ◽

10.17221/4520-jfs ◽

2012 ◽

Vol 52 (No. 9) ◽

pp. 399-409 ◽

Cited By ~ 4

Author(s):

J. Vorčák ◽

J. Merganič ◽

M. Saniga

Keyword(s):

Norway Spruce ◽

Growth Stage ◽

Dead Wood ◽

Developmental Stages ◽

Mineral Soil ◽

Structural Diversity ◽

Virgin Forest ◽

Diameter Structure ◽

Regeneration Processes ◽

Diameter Differentiation

The research was focused on exploring the dynamics and forms of regeneration processes and structural diversity of the Norway spruce virgin forest in Babia hora NNR in relation to altitude. In each developmental stage <br />19 sample plots were established. The structural diversity was assessed by the indices proposed by Clark and Evans (1954), Füldner (1995) and Jaehne and Dohrenbusch (1997). Concerning the spatial distribution of the trees in the virgin forest no tendency to their clustering with the increasing altitude was found in the zones below 1,460 m. The influence of the altitude was confirmed in the zone above 1,461 m where the groups of “family spruces” are typical. Diameter differentiation was significantly higher in the growth stage. Evaluation of this attribute in terms of the altitude detected significant diameter differentiation at an altitude below 1,260 m in the growth stage. According to the Füldner index the virgin forest has generally medium differentiated diameter structure. According to the complex index by Jaehne and Dohrenbusch (1997) the differentiation of the virgin forest decreases with the ascending altitude up to 1,460 m, where the compact forest ends. Evaluation of the seedbed revealed that 46.2% of the naturally regenerated individuals were growing on mineral soil, 52.4% on dead wood and 1.4% on wind-thrown roots. Regarding the developmental stages 46% of the individuals were found in growth stage, 23% in optimum stage and 31% in breakdown stage.

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