scholarly journals A Novel Approach to Evaluate the Effect of Neighboring Trees and the Orientation of Tree Social Area on Stem Radial Increment of Norway Spruce Trees

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 163
Author(s):  
Jan Světlík ◽  
Jan Krejza ◽  
Pavel Bednář
Keyword(s):  
Norway Spruce ◽  
Tree Growth ◽  
Growth Models ◽  
Explanatory Power ◽  
Radial Increment ◽  
Important Indicator ◽  
The Czech Republic ◽  
Novel Approach ◽  
Spruce Stands ◽  
Social Area

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice.

scholarly journals Changes in the nutrition and health status of young Norway spruce stands in the Krkonoše Mts. in a 17-year period

2017 ◽  
Vol 63 (No. 8) ◽  
pp. 344-354
Author(s):  
Novotný Radek ◽  
Lomský Bohumír ◽  
Šrámek Vít
Keyword(s):  
Czech Republic ◽  
Norway Spruce ◽  
Nutrient Concentrations ◽  
Height Increment ◽  
Forest Stands ◽  
Future Health ◽  
The Czech Republic ◽  
N Nutrition ◽  
Spruce Stands ◽  
Spruce Needles

For 17 Norway spruce stands located in the Krkonoše Mts. in the Czech Republic a long-term assessment of defoliation, height increment, foliage concentration of nutrients (N, P, Ca, K, Mg) and stress elements (S, F) was carried out. The results show a decrease of defoliation and a slight increase of height increment, which occur in accordance with the decreasing concentration of sulphur in spruce needles. However, neither sulphur concentration nor height increment trends are significant, suggesting that both the main pollution abatement and the growth resumption took place already in the 1990’s. During the late 1990’s the average spruce defoliation was greater than 35%, while since 2007 it has fluctuated between 18 and 25%, which corresponds with the figures for the forest stands located in the other regions of the Czech Republic. The evaluation of single nutrient concentrations detected occasional deficiencies of P and Mg at individual plots. The good N nutrition (&gt; 15 mg N·g<sup>–1</sup>) in combination with a significantly decreasing trend of P, K and Ca concentrations in Norway spruce needles may potentially constitute a problem in regard to both the future health and the stability of forest stands in the studied region.

scholarly journals Leaf area index of Norway spruce stands in relation to age and defoliation

Beskydy ◽  
2012 ◽  
Vol 5 (2) ◽  
pp. 173-180 ◽  
Author(s):  
R. Pokorný ◽  
S. Stojnič
Keyword(s):  
Health Status ◽  
Norway Spruce ◽  
Strong Relationship ◽  
Stand Age ◽  
Area Index ◽  
The Czech Republic ◽  
Gap Fraction ◽  
Spruce Stands ◽  
Fraction Method ◽  
Forest Practice

This contribution presents LAI data of 17 Norway spruce stands of different age (from 15 to 102 years) and health status (defoliation ranging from 0 to 40 %) located in the Těšínské Beskydy Mts. (NE of the Czech Republic). Defoliation degree was estimated by ocular observation and LAI was estimated indirectly on the base of gap fraction method using LAI-2000 PCA (Li-Cor, USA). It was found that LAI decreased with stand age (approximately from 12.6 to 8.5) whereas defoliation increased. Therefore, strong relationship between defoliation and LAI as well as gap fractions was found. LAI appears valuable parameter for health status of stand evaluation due to linear relationship (r2 = 0.87) between LAI and defoliation. As LAI can be estimated more objectively by a canopy analyzer then the degree of canopy defoliation by ocular observation, there is a perspective for a wide use LAI in forest practice. The LAI values can be used for the evaluation of health status of Norway spruce stands.

scholarly journals Comparison of Spatially and Nonspatially Explicit Nonlinear Mixed Effects Models for Norway Spruce Individual Tree Growth under Single-Tree Selection

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1338
Author(s):  
Simone Bianchi ◽  
Mari Myllymaki ◽  
Jouni Siipilehto ◽  
Hannu Salminen ◽  
Jari Hynynen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Tree Growth ◽  
Cross Validation ◽  
Growth Models ◽  
Forest Growth ◽  
Individual Tree ◽  
Selection Cutting ◽  
Single Tree ◽  
Individual Tree Growth ◽  
Single Tree Selection

Background and Objectives: Continuous cover forestry is of increasing importance, but operational forest growth models are still lacking. The debate is especially open if more complex spatial approaches would provide a worthwhile increase in accuracy. Our objective was to compare a nonspatial versus a spatial approach for individual Norway spruce tree growth models under single-tree selection cutting. Materials and Methods: We calibrated nonlinear mixed models using data from a long-term experiment in Finland (20 stands with 3538 individual trees for 10,238 growth measurements). We compared the use of nonspatial versus spatial predictors to describe the competitive pressure and its release after cutting. The models were compared in terms of Akaike Information Criteria (AIC), root mean square error (RMSE), and mean absolute bias (MAB), both with the training data and after cross-validation with a leave-one-out method at stand level. Results: Even though the spatial model had a lower AIC than the nonspatial model, RMSE and MAB of the two models were similar. Both models tended to underpredict growth for the highest observed values when the tree-level random effects were not used. After cross-validation, the aggregated predictions at stand level well represented the observations in both models. For most of the predictors, the use of values based on trees’ height rather than trees’ diameter improved the fit. After single-tree selection cutting, trees had a growth boost both in the first and second five-year period after cutting, however, with different predicted intensity in the two models. Conclusions: Under the research framework here considered, the spatial modeling approach was not more accurate than the nonspatial one. Regarding the single-tree selection cutting, an intervention regime spaced no more than 15 years apart seems necessary to sustain the individual tree growth. However, the model’s fixed effect parts were not able to capture the high growth of the few fastest-growing trees, and a proper estimation of site potential is needed for uneven-aged stands.

scholarly journals The health and nutritional status of Norway spruce stands in the Krušné hory Mts. 15 years subsequent to the extreme winter of 1995/96

2013 ◽  
Vol 59 (No. 9) ◽  
pp. 359-369 ◽  
Author(s):  
B. Lomský ◽  
V. Šrámek ◽  
R. Novotný
Keyword(s):  
Nutritional Status ◽  
Norway Spruce ◽  
Fluorine Content ◽  
The Czech Republic ◽  
Eastern Area ◽  
Crown Defoliation ◽  
Ridge Area ◽  
Spruce Stands ◽  
Negative Effect

Since 1994, the nutritional status and the air pollution load have been evaluated on 20 research plots, located in young Norway spruce stands in the ridge area of the Kru&scaron;n&eacute; hory Mts. The most recent acute damage to the spruce stands, in the winter of 1995/96, was connected with a long-lasting inversion situation in the eastern area of the Kru&scaron;n&eacute; hory Mts. Today, the health status of the spruce stands, expressed in terms of the crown defoliation, has recovered and is comparable to that found in other regions of the Czech Republic. The sulphur and fluorine content of the needles has decreased significantly. The long-term negative effect of acid deposition that contributes to the degradation of forest soils remains an important part of stressors acting on forest ecosystems in the region. In recent years, nitrogen and sulphur concentrations in the needles have increased slightly again. A long-term tendency towards a decrease in the phosphorus, calcium and potassium content of the needles was detected.&nbsp; &nbsp;

scholarly journals Pruning effect on Norway spruce (Picea abies (L.) Karst.) growth and quality

2017 ◽  
Vol 66 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Endijs Baders ◽  
Janis Donis ◽  
Guntars Snepsts ◽  
Andis Adamovics ◽  
Aris Jansons
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Ring Width ◽  
Stand Density ◽  
Stand Age ◽  
Radial Increment ◽  
Annual Increment ◽  
Management Activity ◽  
Spruce Stands ◽  
Occlusion Rate

Abstract Pruning requires significant investment, therefore, the aim of the study was to characterize occlusion of branch wounds and changes in radial increment as well as frequency of browsing damages after pruning of Norway spruce (Picea abies (L.) Karst.) in order to provide data for financial calculations and recommendations for practical forestry. Altogether 1,614 pruned and 4,368 unpruned trees from 45 Norway spruce stands were measured and cored. Degree of wound occlusion and browsing damages were assessed, and additional volume increment estimated in each stand. Pruning resulted in significant increase of length of branch-free section: for unpruned trees it was 0.3 ± 0.07 m, but for pruned 3.4 ± 0.10 m. Branch wounds for most of the trees (68%) were filled with resin (occluded), for lower share of trees (31%) – still open, but for some trees (1%) completely occluded. Branch wound occlusion rate was not affected by differences in stand density, but was significantly affected by stand age: proportion of trees with occluded branch scars increased with age. Trees with occluded branch wounds had a significantly higher increase in tree ring width after the pruning in comparison to the period before pruning than trees with open branch wounds, emphasizing the importance of radial increment in development of branch-free layer of wood. Pruning resulted in minor (−7% or −0.28 ± 0.05 m3 ha−1) reduction of annual increment that was statistically significant only up to 3 years after this forest management activity for stands younger than 17 years and with mean height up to 10.5 m. Pruned trees were significantly more browsed than unpruned (6.1% and 2.7%, respectively).

scholarly journals THE INTENSIVE MANAGEMENT OF NORWAY SPRUCE: A COMPROMISE BETWEEN FINANCIAL GAIN AND GENETIC DIVERSITY?

2019 ◽  
Vol 1 ◽  
pp. 11
Author(s):  
Solveiga Luguza ◽  
Endijs Bāders ◽  
Pauls Zeltiņš ◽  
Roberts Čakšs ◽  
Dainis Edgars Ruņģis ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Norway Spruce ◽  
Rotation Period ◽  
Seed Orchard ◽  
Raw Material ◽  
Plant Production ◽  
Radial Increment ◽  
Negative Consequences ◽  
Spruce Stands ◽  
The Impact

INTRODUCTION Norway spruce (Picea abies (L.) Karst.) is a high-yielding commercial tree species grown in the Baltic sea region. It not only ensures timber production, but also provides a notable amount of crown branch biomass and a substantial amount of technically accessible stump biomass for energy. Thus, it has a high potential as a source of renewable materials and energy in the bioeconomy. Recent studies in Latvia have shown no long-term negative consequences to forest ecosystems from whole-tree harvesting. Hence, this management method can be considered sustainable for Norway spruce stands in fertile mineral soils. Not only yield, but also risks need to be considered to ensure financial sustainability, mainly the impact of wind-storms, drought, and pests. A combination of silviculture and genetics (tree breeding) can be used to reduce the probability of damage to Norway spruce stands. The aim of our study was to assess the potential of simultaneously ensuring both genetic gain and diversity in Norway spruce plantations. MATERIALS AND METHODS Data characterizing/showing tree growth – current height, diameter at breast height, survival, as well as radial increment (increment cores) – were obtained from a 50-year-old Norway spruce plantation. Data characterizing genetic diversity were collected from a gene reserve stand (48 trees), Norway spruce seed orchard progenies consisting of 20 clones, as well as 12 pure Norway spruce stands. DNA was extracted and analysed with 6 to 14 nuclear SSR markers. RESULTS No significant differences were observed between the seed orchard progenies, the trees from the gene reserve stand and other Norway spruce stands using the assessed parameters – allelic richness, observed heterozygosity, genetic diversity and relatedness. This indicates that the use of a seed orchard containing a relatively low number of clones as a seed source for plant production and forest regeneration would not have a negative impact on genetic diversity. However, notable gains in productivity can be achieved using selected plant material. At the age of 50 years, phenotypically selected clones in the low-density (5×5m) plantation had a mean yield of 327±42 m3ha-1, significantly exceeding the mean yield (277±56 m3ha-1) observed in Norway spruce stands of the same age and the same site conditions (forest type), while no significant differences were observed compared to the average stand yield at the age of 80 years (347±47 m3ha-1). The target diameter of 31 cm was reached at the age of 42±0.9 years on average, but this varied significantly among clones. CONCLUSION The results demonstrate a notable potential to reduce the rotation period, thereby: a) increasing the availability of raw material for further processing and energy production, and b) reducing financial risks due to lowering the probability that the stand will sustain substantial damage (i.e. wind storm). This gain can be achieved without significantly compromising genetic diversity. Further studies shall address potential changes in genetic diversity at the landscape level over a longer period when using a very limited set of clones. Stands in nature reserves could serve as a basis for comparison in such studies.

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