scholarly journals Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

2021 ◽  
Author(s):  
Kirsten Höwler ◽  
Torsten Vor ◽  
Peter Schall ◽  
Peter Annighöfer ◽  
Dominik Seidel ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Mixed Forest ◽  
European Beech ◽  
Forest Stands ◽  
Species Identity ◽  
Mixed Stands ◽  
Mixed Forests ◽  
Climate Conditions ◽  
Timber Quality ◽  
Positive Effects

AbstractResearch on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on the effects of tree species mixing on timber quality. In particular, it is still unclear whether the numerous positive effects of mixed forests on productivity and stability come at the expense of timber quality. In this study, we used photographs of sawn boards from 90 European beech (Fagus sylvatica L.) trees of mixed and pure forest stands to analyze internal timber quality through the quality indicator knot surface that was quantitatively assessed using the software Datinf® Measure. We observed a decrease in knot surface with increasing distance from the pith as well as smaller values in the lower log sections. Regarding the influence of neighborhood species identity, we found only minor effects meaning that timber qualities in mixed stands of beech and Norway spruce (Picea abies (L.) H. Karst.) tended to be slightly worse compared to pure beech stands.

scholarly journals Object Oriented Classification for Mapping Mixed and Pure Forest Stands Using Very-High Resolution Imagery

2021 ◽  
Vol 13 (13) ◽  
pp. 2508
Author(s):  
Loredana Oreti ◽  
Diego Giuliarelli ◽  
Antonio Tomao ◽  
Anna Barbati
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Parametric Method ◽  
Mixed Forest ◽  
Mixed Stands ◽  
Mapping Unit ◽  
Mixed Forests ◽  
High Resolution Imagery ◽  
Very High Resolution Imagery ◽  
Very High

The importance of mixed forests is increasingly recognized on a scientific level, due to their greater productivity and efficiency in resource use, compared to pure stands. However, a reliable quantification of the actual spatial extent of mixed stands on a fine spatial scale is still lacking. Indeed, classification and mapping of mixed populations, especially with semi-automatic procedures, has been a challenging issue up to date. The main objective of this study is to evaluate the potential of Object-Based Image Analysis (OBIA) and Very-High-Resolution imagery (VHR) to detect and map mixed forests of broadleaves and coniferous trees with a Minimum Mapping Unit (MMU) of 500 m2. This study evaluates segmentation-based classification paired with non-parametric method K- nearest-neighbors (K-NN), trained with a dataset independent from the validation one. The forest area mapped as mixed forest canopies in the study area amounts to 11%, with an overall accuracy being equal to 85% and K of 0.78. Better levels of user and producer accuracies (85–93%) are reached in conifer and broadleaved dominated stands. The study findings demonstrate that the very high resolution images (0.20 m of spatial resolutions) can be reliably used to detect the fine-grained pattern of rare mixed forests, thus supporting the monitoring and management of forest resources also on fine spatial scales.

Competition theory — science and application in mixed forest stands: review of experimental and modelling methods and suggestions for future research

2013 ◽  
Vol 21 (2) ◽  
pp. 71-84 ◽  
Author(s):  
Guy R. Larocque ◽  
Nancy Luckai ◽  
Shailendra N. Adhikary ◽  
Arthur Groot ◽  
F. Wayne Bell ◽  
...  
Keyword(s):  
Mixed Forest ◽  
Single Species ◽  
Experimental Designs ◽  
Competitive Interactions ◽  
Future Research ◽  
Relative Importance ◽  
Forest Stands ◽  
Management Scenarios ◽  
Mixed Stands ◽  
Individual Tree

Competition in forest stands has long been of interest to researchers. However, much of the knowledge originates from empirical studies that examined the effects of competition. For instance, many studies were focused on the effects of the presence of herbaceous species on the development of tree seedlings or the decrease in individual tree growth with increases in stand density. Several models that incorporate competitive effects have been developed to predict tree and stand growth, but with simplified representations of competitive interactions. While these studies provided guidance useful for forest management, they contributed only partially to furthering our understanding of competitive mechanisms. Also, most competition studies were conducted in single-species stands. As competitive interactions occurring in mixed stands are characterized by a higher degree of complexity than those in single-species stands, a better understanding of these mechanisms can contribute to developing optimal management scenarios. The dynamics of forest stands with at least two species may be affected not only by competition, but also by facilitation or complementarity mechanisms. Thus, knowledge of the mechanisms may provide insight into the relative importance of intra- versus inter-specific competition and whether competition is symmetric or asymmetric. Special attention to the implementation of field experimental designs is warranted for mixed stands. While traditional spacing trials are appropriate for single-species stands, the examination of competitive interactions in mixed stands requires more complex experimental designs to examine the relative importance of species combinations. Forest productivity models allow resource managers to test different management scenarios, but again most of these models were developed for single-species stands. As competitive interactions are more complex in mixed stands, models developed to predict their dynamics will need to include more mechanistic representations of competition.

Crown structure of European beech (Fagus sylvatica L.): a non-causal proxy for mechanical–physical wood properties

2020 ◽  
Author(s):  
Andreas Rais ◽  
Martin Jacobs ◽  
Jan-Willem G. van de Kuilen ◽  
Hans Pretzsch
Keyword(s):  
Fagus Sylvatica ◽  
Laser Scanning ◽  
European Beech ◽  
Wood Properties ◽  
Projection Area ◽  
Mixed Stands ◽  
Crown Volume ◽  
Crown Structure ◽  
Crown Morphology ◽  
Crown Projection Area

The current tendency towards the silvicultural promotion of mixed tree species has increased the variability in the crown structure within stands. This study shows how neighbouring trees can influence both the external crown features and internal wood properties of trees. Using terrestrial laser scanning, the crown features of 100 European beech trees, <i>Fagus sylvatica</i> L., from pure beech stands and mixed stands of beech with Douglas fir, Norway spruce, sessile oak and Scots pine were recorded. After felling and sawing, the dynamic modulus of elasticity was determined on 1623 boards from the two lower 4.1-m logs. Significant differences were found between beech trees from pure stands and those from beech–pine mixed stands in terms of crown volume (415 m<sup>3</sup> vs 766 m<sup>3</sup>), crown ratio (50.0% vs 71.5%), crown projection ratio (0.182 m cm<sup>−1</sup> vs 0.253 m cm<sup>−1</sup>) and branch angle (30.7° vs 54.1°). Multiple regression mixed models revealed significant relationships between timber stiffness and crown volume (-1.7 N mm<sup>−2</sup> m<sup>−3</sup>), crown ratio (-28.4 N mm<sup>−2</sup> %<sup>−1</sup>) and crown projection area (-9835 N mm<sup>−2</sup> m<sup>−1</sup> cm). Thus, the crown morphology of broad-leaved species reflects the tree’s long-term competitive status and suggests indicators for the assessment of mechanical–physical wood properties.

scholarly journals Application of the BDq method to complex tropical mixed forest ecosystems in Nigeria

2021 ◽  
Vol 349 ◽  
pp. 41-54
Author(s):  
Friday Nwabueze OGANA ◽  
José Javier GORGOSO-VARELA ◽  
Alfred Ossai ONEFELI
Keyword(s):  
Forest Ecosystems ◽  
Management Practice ◽  
Mixed Forest ◽  
Basal Area ◽  
Selection Method ◽  
Maximum Diameter ◽  
Mixed Stands ◽  
Mixed Forests ◽  
Breast Height ◽  
Silvicultural Treatments

The absence of management practice/silvicultural treatments in the complex tropical mixed forests of Nigeria has led to uncontrolled logging in natural forest stands and loss of biodiversity. To sustain production, protection and conservation in these complex tropical mixed stands, this study proposes the application of a selection method – the BDq method (B: basal area, D: maximum diameter, q-ratio) to manage these stands. Two strata were used as a pilot test: stratum 1 consisted of 15 plots and stratum 2 of 7 plots, each with an area of 0.25 ha. Only trees with a diameter at breast height (d) ≥ 10.0 cm were considered in this study. Harvesting with the BDq method was quantified, by setting B at 20 m2, 25 m2 and 30 m2/ha corresponding respectively to intensive, medium and light harvesting regimes. D was set at 65 cm and the q-ratio was computed for each plot. The results showed that the three BDq regimes prescribed (intensive, medium and light) yielded reasonable felling intensities (FI), derived as the percentage of extracted volume (Vext) and biomass (Wext). The Vext and FI for stratum 1 ranged from 39.94-62.30 m3/ha and 11.22-18.18%; the results for stratum 2 were 30.44-51.33 m3/ha and 10.02-17.57%. For biomass, the Wext and FI ranged from 18.46-29.82 t/ha and 9.40-15.95% for stratum 1 and 14.16-24.82 t/ha and 9.73-17.50% for stratum 2. These findings show that applying the BDq method to the complex tropical mixed forests of Nigeria would yield attractive stands.

scholarly journals Effects of gap size on natural regeneration and micro-environmental soil conditions in European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst) dominated mixed forest

2020 ◽  
Vol 66 (No. 12) ◽  
pp. 607-615
Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Fagus Sylvatica ◽  
Natural Regeneration ◽  
Mixed Forest ◽  
European Beech ◽  
Soil Conditions ◽  
Gap Size ◽  
The Czech Republic ◽  
Fagus Sylvatica L

The study focused on the effects of gap size on natural regeneration of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies L.) and micro-environmental soil conditions in gaps of different sizes under temperate mixed forest in the Czech Republic. Six gaps comprising two for small (≥ 200 m<sup>2</sup>), medium (≥ 500 m<sup>2</sup>) and big (≥ 900 m<sup>2</sup>) each were selected. Ten circular 1 m<sup>2</sup> subsampling plots were established at 2 m intervals along individual North-South-East-West transects, including one at the gap centre. Regeneration was monitored in 2014 and repeatedly in 2019. Soil conditions were only measured in 2019. Gap size was found to be a significant parameter for European beech natural regeneration in 2014. Besides, the quick occupation of European beech in gaps at natural beech zone provoked its prolific regeneration compared to Norway spruce in 2014. However, in 2019 the recent threat of weather variabilities was responsible for the general abysmal growth performance of natural regeneration. Division of gap microsites into different within-gap positions based on prevailing light or shade conditions was helpful in assessing the significant variations of soil conditions within-gap positions and among gap sizes. Soil temperature and moisture significantly influenced the regeneration of European beech and Norway spruce, respectively.  

Canopy transpiration of pure and mixed forest stands with variable abundance of European beech

2012 ◽  
Vol 442-443 ◽  
pp. 2-14 ◽  
Author(s):  
Tobias Gebauer ◽  
Viviana Horna ◽  
Christoph Leuschner
Keyword(s):  
Mixed Forest ◽  
European Beech ◽  
Forest Stands ◽  
Canopy Transpiration

scholarly journals Tree species identity mediates mechanisms of top soil carbon sequestration in a Norway spruce and European beech mixed forest

2016 ◽  
Vol 73 (2) ◽  
pp. 437-447 ◽  
Author(s):  
Enrique Andivia ◽  
Victor Rolo ◽  
Mathieu Jonard ◽  
Pavel Formánek ◽  
Quentin Ponette
Keyword(s):  
Carbon Sequestration ◽  
Soil Carbon ◽  
Norway Spruce ◽  
Tree Species ◽  
Mixed Forest ◽  
European Beech ◽  
Soil Carbon Sequestration ◽  
Species Identity ◽  
Top Soil

scholarly journals Characteristics of coniferous and mixed forest types in the basins of Belaya and Malaya Laba rivers (North-Western Caucasus)

2021 ◽  
Vol 35 ◽  
pp. 00020
Author(s):  
Yulia Sablirova ◽  
Fatimat Tembotova ◽  
Rustam Pshegusov
Keyword(s):  
Forest Regeneration ◽  
Age Groups ◽  
Mixed Forest ◽  
Forest Types ◽  
Forest Stands ◽  
Western Caucasus ◽  
Mixed Forests ◽  
High Productivity ◽  
Mixed Age ◽  
North Western

Based on the results of the studies conducted in the forest areas of the basins of the rivers Belaya and Malaya Laba, there has been compiled a typological scheme of the coniferous and mixed forests of North-Western Caucasus (NWC) which included 21 forest types, that are distributed into 12 groups. The forest stands of the studied forests types is predominantly complex in composition: mixed-age groups, multi-tiered, medium to high productivity, medium to high-density. The forest regeneration is weak or very weak, according to the scale proposed by S. M. Bebia. The data obtained during the research can be used for assessing the dynamics of the forest biogeocenoses, biodiversity, as well as successional processes.

Allozyme variation among european beech (Fagus sylvatica L.) stands in Bosnia and Herzegovina

2016 ◽  
Vol 27 (3-4) ◽  
pp. 5-15
Author(s):  
S. Kvesić ◽  
D. Ballian ◽  
T. V. Parpan
Keyword(s):  
Bosnia And Herzegovina ◽  
Fagus Sylvatica ◽  
European Beech ◽  
Allozyme Variation ◽  
Forest Tree ◽  
Ex Situ ◽  
Mixed Stands ◽  
Common Beech ◽  
Fagus Sylvatica L ◽  
Forest Lands

From the economical and ecological point of view, beech (Fagus sylvatica L.) is one of the most important forest tree species in Bosnia and Herzegovina. To understand the significance of beech forests, something about the structure of forests and forest lands needs to be said. Bosnia and Herzegovina has 3.231.500 hectares of forests and forest land, which is about 60% of its surface. In the forest and forest lands structure, we can see that it has high forest occupying 51.1% of the forest area, coppice occupying 38.70%, shrubs occupying 4%, bare land and clearings occupying 5.80% and other unproductive areas occupying 0.40%. Beech can be found in mixed stands of beech and fir, as well as stands of beech, fir and spruce that occupy 46% of all high forests. Thus, the total area of ​​forests where the beech is found is approximately 1.652.400 hectares. The aim of the study was to carry out the analysis of genetic structures of natural beech populations in Bosnia and Herzegovina by using isoenzyme markers. Conducting a biochemical genetic structure analysis of 14 beech populations, using 10 enzyme systems with 16 isoenzyme gene loci, we found significant differences. Variability in some gene loci is large, while some populations for some gene loci showed monomorphism. The results indicate that in order to maintain natural genetic resources of common beech in Bosnia and Herzegovina, there should be a dense network of gene reserves established. This network from one of the Balkan countries should then become a constituent part of all-European network. These gene banks need in situ and ex situ methods (seed banks, seed stands, and seed orchards) to maintain the genetic diversity of populations. Based on the research results, every ecological niche of common beech i.e. their genetic variation should be conserved regarding the appropriate number of populations and individuals to preserve the ecological and physiological features of this valuable commercial species. 

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