scholarly journals Effect of Bark-Stripping on Mechanical Stability of Norway Spruce

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 357 ◽  
Author(s):  
Oskars Krisans ◽  
Renate Saleniece ◽  
Steffen Rust ◽  
Didzis Elferts ◽  
Rolands Kapostins ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Mechanical Stability ◽  
Direct Reduction ◽  
Bending Moment ◽  
Stem Volume ◽  
P Value ◽  
Bark Stripping ◽  
Stem Wood ◽  
Secondary Failure ◽  
Linear Predictors

The increasing effects of storms are considered the main abiotic disturbance affecting forest ecosystems. Bark-stripping damage from the growing ungulate populations, in turn, are among the main biotic risks, which might burden the stability of trees and stands. Therefore, the aim of our study is to estimate the effect of cervid bark-stripping on the mechanical stability of Norway spruce using a static tree-pulling test. For the test, eight damaged and 11 undamaged canopy trees were selected from a 40-year old stand (plantation with 1 × 3 m spacing) growing on mineral mesotrophic soil. The selected trees were bark-stripped 7–9 years prior to the experiment. Uprooting was the most frequent type of failure; only two trees broke at the stem. For the damaged trees, the resistance to pulling was significantly reduced (p-value < 0.001). Stem volume and presence of bark-stripping were the best linear predictors of the basal bending moment at the primary failure (irreversible deformation of wood structure) and secondary failure (collapse of the tree). A significant (p-value < 0.001) interaction between stem–wood volume and presence of bark-stripping was observed for primary failure, indicating a size-dependent reduction of stability of the damaged trees. Such interaction lacked significance (p-value = 0.43) for the secondary failure (mostly uprooting), indicating a decrease in stability irrespectively of tree size. Somewhat surprisingly, the decrease in the overall mechanical stability of the bark-stripped trees appeared not to be related to a direct reduction of the strength of the stems, but rather to physiological effects such as altered allocation of carbon, increased drought stress because of interfered hydraulic conductance of wood, or secondary infestation. The reduced stability also suggests that bark-stripped trees can act as the weak spots decreasing the collective stability of stands in the long term, thus increasing the susceptibility to storms.

scholarly journals The effect of root rot and bark-stripping on wind stability of Norway spruce (Picea abies (L.) H. Karst.) = Parastās egles (Picea abies (L.) H. Karst.) vēja noturības izmaiņas sakņu trupes un stumbra mizas bojājumu ietekmē

2020 ◽  
Author(s):  
◽  
Oskars Krisans ◽  
Keyword(s):  
Climate Change ◽  
Picea Abies ◽  
Norway Spruce ◽  
Root Rot ◽  
Mechanical Stability ◽  
Stem Volume ◽  
Natural Disturbances ◽  
Bark Stripping ◽  
Secondary Failure ◽  
Spruce Stands

Climate change causes gradual decline of economic value of Norway spruce forestry except in boreal and hemiboreal forest zones that will remain suitable for this tree species. However, also in this region frequency and scale of damages caused by natural disturbances (abiotic and biotic factors) are expected to increase. Norway spruce will remain its economic significance and role in carbon sequestration in Latvia, if forest management practices will be changed to prevent or minimize the damages caused by natural disturbances. Information on effect of natural disturbances and their interactions on trees is vital for development of recommendations for adaptation of forestry to climate change. The aim of the thesis is to assess the effect of root rot and bark-stripping on possibility of wind induced damages in Norway spruce stands. Tree mechanical stability was primarily determined by its stem volume; however, the presence of damages, caused by biotic agents, such as root rot and bark-stripping, significantly reduced it. Morphometric parameters of Norway spruce stem and root plate differed significantly between stands on drained peat and mineral soils. Root-rot notably and significantly affected mechanical stability of trees regardless of soil type and volume of root-soil plate, resulting in similar reduction of wind load necessary to cause both primary and secondary failure. Consequences of bark-stripping primarily affected root-soil anchorage, more commonly causing uprooting than stem fracture. Most pronounced was reduction of resistance against primary failure. Changing wind climate, high population density of cervids and presence of root-rot will lead to increased risk of damages caused by (repeated) storms and subsequent legacy effects. The survival of forest stands depends on dimensions of trees and exposure time to different damaging agents, and, at current climate and silvicultural practice, was significantly reduced when transitioning into third age class (41-60 years). Targeted forestry, ensuring planting of improved material, lower initial density, timely precommercial thinning and thus ensuring faster reach of the tree dimension required for final harvest will reduce the time when stands are subjected to significant wind damage risk, thus minimizing the possibility of such disturbance and boosting value of Norway spruce stands.

scholarly journals Effects of Bark Stripping on Timber Production and Structure of Norway Spruce Forests in Relation to Climatic Factors

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 320 ◽  
Author(s):  
Jan Cukor ◽  
Zdeněk Vacek ◽  
Rostislav Linda ◽  
Stanislav Vacek ◽  
Petr Marada ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Radial Growth ◽  
Climatic Factors ◽  
Cervus Nippon ◽  
Climatic Conditions ◽  
Stem Volume ◽  
Forest Stands ◽  
Bark Stripping ◽  
Karst Forest ◽  
Production Parameters

The aim of this study was to assess the effects of bark stripping caused by sika deer (Cervus nippon [Temminck]) on the production and structure of young Norway spruce (Picea abies L. Karst) forest stands (41–43 years). Production parameters, structure, diversity, and the dynamics of radial growth in selected forest stands in relation to climatic conditions were evaluated. Similar to other production parameters, stand volumes showed lower values on research plots heavily damaged by bark stripping (290 m3 ha−1) compared to stands with lower tree stem damages (441 m3 ha−1). A significant decrease in stem volume was recorded for trees with stem circumference damage higher than 1/3 of the stem circumference. In most cases, the trees were damaged between the ages of 10–23 years, specifically the radial growth was significantly lowered in this period. The diameter increment of damaged trees dropped to 64% of the healthy counterparts in this period. Bark stripping damages reached up to 93% of the stem circumference with a mean damage of 31%. Stem rot was found on 62% of damaged trees. In our study area, with respect to the terms of climatic conditions, precipitation had a higher effect on radial growth of the Norway spruce compared to temperature. The main limiting climatic factor of tree growth was the lack of precipitation within a growing season, particularly in June of the current year.

Analysis of stand density effects on the stem form of Norway spruce trees and volume miscalculation by traditional form factor equations using terrestrial laser scanning (TLS)

2020 ◽  
Vol 50 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Martin Jacobs ◽  
Andreas Rais ◽  
Hans Pretzsch
Keyword(s):  
Form Factor ◽  
Norway Spruce ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Volume Estimation ◽  
Tree Level ◽  
Stem Volume ◽  
Stem Form ◽  
Stem Wood ◽  
Volume Estimates

Tree and stand volume estimates are relevant for forest inventories, forest sales, and carbon stock evaluations. Forest practice commonly uses generalized stem-wood volume functions; however, such generalized approaches neglect the stem form in detail. Hence, trees of a given species with the same diameter at breast height (d1.3) and height (h) are always assumed to have the same form factor and thus the same volume. This case study focused on stem form variation of Norway spruce (Picea abies (L.) Karst.) due to competition effects. Using terrestrial laser scanning (TLS), we measured the stem shape of 868 trees from a long-term spacing and thinning experiment in Germany. The plots covered a broad density range. We analysed the effect of competition and compared the TLS-determined stem volume estimates with those determined conventionally. TLS-based volume estimations showed that the lower the competition was, the lower the tree volume was with a given d1.3 and h. Commonly used functions underestimated the volume stock overall by 4.2%, disregarding any levels. At plot level, underestimation varied from 0.7% to 7.0%. At tree level, the volume was under- and over-estimated by −10% to +10%, respectively. The more precise the examination was, the more suitable the application of TLS was for enhancing volume estimation.

scholarly journals Annular Defects Impair the Mechanical Stability of the Intervertebral Disc

2021 ◽  
pp. 219256822110060
Author(s):  
Jun-Xin Chen ◽  
Yun-He Li ◽  
Jian Wen ◽  
Zhen Li ◽  
Bin-Sheng Yu ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Degrees Of Freedom ◽  
Mechanical Stability ◽  
Biomechanical Testing ◽  
Bending Stiffness ◽  
Biomechanical Study ◽  
Torsional Stiffness ◽  
P Value ◽  
Lateral Bending ◽  
Flexion Extension

Study Design: A biomechanical study. Objectives: The purpose of this study was to investigate the effects of cruciform and square incisions of annulus fibrosus (AF) on the mechanical stability of bovine intervertebral disc (IVD) in multiple degrees of freedom. Methods: Eight bovine caudal IVD motion segments (bone-disc-bone) were obtained from the local abattoir. Cruciform and square incisions were made at the right side of the specimen’s annulus using a surgical scalpel. Biomechanical testing of three-dimensional 6 degrees of freedom was then performed on the bovine caudal motion segments using the mechanical testing and simulation (MTS) machine. Force, displacement, torque and angle were recorded synchronously by the MTS system. P value <.05 was considered statistically significant. Results: Cruciform and square incisions of the AF reduced both axial compressive and torsional stiffness of the IVD and were significantly lower than those of the intact specimens ( P < .01). Left-side axial torsional stiffness of the cruciform incision was significantly higher than a square incision ( P < .01). Neither incision methods impacted flexional-extensional stiffness or lateral-bending stiffness. Conclusions: The cruciform and square incisions of the AF obviously reduced axial compression and axial rotation, but they did not change the flexion-extension and lateral-bending stiffness of the bovine caudal IVD. This mechanical study will be meaningful for the development of new approaches to AF repair and the rehabilitation of the patients after receiving discectomy.

scholarly journals Assessment of Stem Volume on Plots Using Terrestrial Laser Scanner: A Precision Forestry Application

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 301
Author(s):  
Dimitrios Panagiotidis ◽  
Azadeh Abdollahnejad ◽  
Martin Slavík
Keyword(s):  
Norway Spruce ◽  
Laser Scanner ◽  
Estimation Methods ◽  
Coefficient Of Determination ◽  
Stem Volume ◽  
Small Scale ◽  
Terrestrial Laser Scanner ◽  
Precision Forestry ◽  
Total Tree ◽  
European Oak

Timber volume is an important asset, not only as an ecological component, but also as a key source of present and future revenues, which requires precise estimates. We used the Trimble TX8 survey-grade terrestrial laser scanner (TLS) to create a detailed 3D point cloud for extracting total tree height and diameter at breast height (1.3 m; DBH). We compared two different methods to accurately estimate total tree heights: the first method was based on a modified version of the local maxima algorithm for treetop detection, “HTTD”, and for the second method we used the centers of stem cross-sections at stump height (30 cm), “HTSP”. DBH was estimated by a computationally robust algebraic circle-fitting algorithm through hierarchical cluster analysis (HCA). This study aimed to assess the accuracy of these descriptors for evaluating total stem volume by comparing the results with the reference tree measurements. The difference between the estimated total stem volume from HTTD and measured stems was 2.732 m3 for European oak and 2.971 m3 for Norway spruce; differences between the estimated volume from HTSP and measured stems was 1.228 m3 and 2.006 m3 for European oak and Norway spruce, respectively. The coefficient of determination indicated a strong relationship between the measured and estimated total stem volumes from both height estimation methods with an R2 = 0.89 for HTTD and R2 = 0.87 for HTSP for European oak, and R2 = 0.98 for both HTTD and HTSP for Norway spruce. Our study has demonstrated the feasibility of finer-resolution remote sensing data for semi-automatic stem volumetric modeling of small-scale studies with high accuracy as a potential advancement in precision forestry.

scholarly journals Evaluation of the provenance plot “Hrubá Skála” (Northern Bohemia) with grand fir at the age of 36 years

2017 ◽  
Vol 63 (No. 2) ◽  
pp. 75-87 ◽  
Author(s):  
Fulín Martin ◽  
Novotný Petr ◽  
Podrázský Vilém ◽  
Beran František ◽  
Dostál Jaroslav ◽  
...  
Keyword(s):  
Czech Republic ◽  
Norway Spruce ◽  
Coastal Region ◽  
Tree Height ◽  
Douglas Fir ◽  
Stem Volume ◽  
Silver Fir ◽  
The Czech Republic ◽  
The North ◽  
Oregon Cascades

The article aims to evaluate the research provenance plot established in 1980 in locality No. 214 – Hrubá Skála (in the north of the Czech Republic), where nine provenances of grand fir (Abies grandis (Douglas ex D. Don) Lindley) provided in the framework of the International Union of Forest Research Organizations project, and one provenance of grand fir, Norway spruce, silver fir and Douglas-fir from a standard commercial source are tested. We present the results of tree height, stem DBH, stem volume production and health status after 36 years. The results correspond with similar experiments in the Czech Republic and abroad and suggest that grand fir provenances from Vancouver Island (British Columbia, Canada) and the Washington (USA) State coastal region show the best production features, while the Oregon Cascades, Idaho and Montana provenances grow more slowly. Comparison with other tree species indicates that the production of grand fir at the investigated age exceeds the production of both Norway spruce and silver fir, and equalizes or gently exceeds even Douglas-fir.

scholarly journals Damage by deer barking and browsing and subsequent rots in Norway spruce stands of Forest Range MoP.

2012 ◽  
Vol 50 (No. 1) ◽  
pp. 24-30 ◽  
Author(s):  
Čermák ◽  
J. Glogar ◽  
L. Jankovský
Keyword(s):  
Norway Spruce ◽  
Red Deer ◽  
Financial Loss ◽  
Bark Stripping ◽  
Age Class ◽  
Spruce Stands ◽  
Financial Losses ◽  
Forest District ◽  
Extensive Damage

The paper deals with the determination of the rate of damage by deer barking and browsing, the subsequent rot caused by Stereum sanguinolentum and the rate of its progress, elucidates causes of damage and quantifies volume and financial losses in the region of Forest Range Mořkov, Forest District Fren&scaron;t&aacute;t pod Radho&scaron;těm. In the most damaged 2<sup>nd</sup> age class, decay by Stereum sanguinolentum was recorded in 59% of damaged trees. The progress of rot ranged from 1 to 70 cm/year. The high number of red deer is considered to be the main reason of extensive damage by bark stripping in the Forest Range Mořkov. The actual financial loss caused by depreciation of wood by the rot is greatest in the 5<sup>th</sup> age class amounting to CZK 64,320 per ha.

scholarly journals Presence of Root Rot Reduces Stability of Norway Spruce (Picea abies): Results of Static Pulling Tests in Latvia

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 416 ◽  
Author(s):  
Oskars Krisans ◽  
Roberts Matisons ◽  
Steffen Rust ◽  
Natalija Burnevica ◽  
Lauma Bruna ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Root Rot ◽  
Rotation Period ◽  
Wind Damage ◽  
Individual Tree ◽  
Study Region ◽  
Secondary Failure ◽  
The Future ◽  
Spruce Stands ◽  
Individual Trees

Storms are the main abiotic disturbance in European forests, effects of which are expected to intensify in the future, hence the importance of forest stand stability is increasing. The predisposition of Norway spruce to wind damage appears to be enhanced by pathogens such as Heterobasidion spp., which reduce stability of individual trees. However, detailed information about the effects of the root rot on the stability of individual trees across diverse soil types is still lacking. The aim of the study was to assess the effect of root rot on the individual tree stability of Norway spruce growing on drained peat and mineral soils. In total, 77 Norway spruce trees (age 50–80 years) growing in four stands were tested under static loading. The presence of Heterobasidion spp. had a significant negative effect on the bending moment at primary and secondary failure of the tested trees irrespectively of soil type. This suggests increased legacy effects (e.g., susceptibility to pathogens and pests due to fractured roots and altered water uptake) of storms. Damaged trees act as weak spots increasing the susceptibility of stands to wind damage, thus forming a negative feedback loop and contributing to an ongoing decline in vitality of Norway spruce stands following storms in the study region in the future. Accordingly, the results support the importance of timely identification of the decayed trees, lowering stand density and/or shortening rotation period as the measures to counteract the increasing effects of storms on Norway spruce stands.

scholarly journals Production impacts of forest tree breeding on an example of Norway spruce

2010 ◽  
Vol 56 (No. 8) ◽  
pp. 348-352
Author(s):  
J. Kobliha ◽  
M. Slávik ◽  
V. Hynek ◽  
J. Klápště ◽  
J. Stejskal
Keyword(s):  
Norway Spruce ◽  
Economic Efficiency ◽  
Growth Parameters ◽  
Tree Breeding ◽  
Forest Tree ◽  
Stem Volume ◽  
Forest Tree Breeding ◽  
The Mean

The present paper evaluates the height, diameter and stem volume of parental tree progenies. These Norway spruce progenies are compared with the control estimated from tables. The control was overperformed in all measured growth parameters. Heights of selected spruce progenies at the age of 26 years ranged from 9.2 m (K10) to 10.7 m (K2). The control height was 6.4 m. In the evaluation of diameters, progeny K4 showed the best mean dbh (13.7 cm) while the progeny K17 was rated as the thinnest (10.5 cm). We compared these data with the control diameter of 6.5 cm. The mean volumes of selected material varied from 0.097 m<sup>3 </sup>(K9) to 0.047 m<sup>3 </sup>(K17) while the kontrol presented 0.0172 m<sup>3</sup>. Keywords: economic efficiency; forest tree breeding; growth; Norway spruce; production

scholarly journals Adaptation Capacity of Norway Spruce Provenances in Western Latvia

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 840 ◽  
Author(s):  
Zeltiņš ◽  
Katrevičs ◽  
Gailis ◽  
Maaten ◽  
Desaine ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Norway Spruce ◽  
Minimum Temperature ◽  
Transfer Functions ◽  
Rotation Period ◽  
Stem Volume ◽  
Mean Annual Temperature ◽  
Moisture Index ◽  
Adaptation Capacity

In Europe, numerous Norway spruce (Picea abies L. Karst.) provenance trials have been established and evaluated at a juvenile age. Still, information about the adaptation potential and long-term fitness of transferred seedlots in the Baltic Sea region is lacking. The aim of the study was to evaluate the adaptation capacity of provenances and assess the patterns of their long-term reaction to environmental transfer. We examined a 32-year-old provenance trial in the mild Baltic Sea coastal climate of Western Latvia. Significant differences in height and stem volume were observed among provenances. Growth superiority for certain local and Carpathian provenances was maintained over more than one-third of the rotation period. The best predictor of climate transfer functions was minimum temperature of the coldest month at the place of origin, explaining 28% variation in tree height. Populations from sites with more frost days and a colder mean annual temperature, minimum temperature, and lower annual heat-moisture index than the planting site were generally taller.

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