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

Author(s):  
Andreas Rais ◽  
Martin Jacobs ◽  
Jan-Willem G. van de Kuilen ◽  
Hans Pretzsch

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.

Author(s):  
Kirsten Höwler ◽  
Torsten Vor ◽  
Peter Schall ◽  
Peter Annighöfer ◽  
Dominik Seidel ◽  
...  

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.


Author(s):  
А. M. Galasheva ◽  
Е. N. Sedov

For the first time in the world and in Russia, Academician of the Russian Academy of Sciences, breeder Evgeny Nikolaevich Sedov created a series of triploid apple cultivars from intervalent crosses 2х × 4х. Triploid apple cultivars bear fruit more regularly, have higher self-fruitfulness and have fruits of high marketability. The article presents data on the study of triploid apple cultivars of the summer ripening period of the VNIISPK breeding - Augusta, Daryona, Maslovskoye, Osipovskoye, Zhilinskoye, Spasskoye and Yablochny Spas as well as the control Canadian cultivar Melba on a semi-dwarf clone rootstock 54-118. Maslovskoye, Zhilinskoye, Spasskoye and Yablochny Spas have immunity to scab. The orchard was planted in 2014, the garden planting scheme was 5 x 2 m. The indicators of the growth force (tree height, crown width and stem diameter) and the yield of trees were studied. At the age of six, the trees of triploid cultivars reached a height of 2.2 m (Maslovskoye) to 3.0 m (Yablochny Spas) on a semi-dwarf rootstock 54-118. The highest indicators of crown volume (3.3-5.3 m3), crown projection area (4.2-5.3 m2) and the cross-sectional area of the stem (46.5-52.8 cm2) were in Osipovskoye, Yablochny Spas, Zhilinskoye and Spasskoye. The highest yield in an average of three years was given by triploid scab-immune apple cultivars on a semi-dwarf rootstock 54-118: Maslovskoye, Zhilinskoye, Spasskoye and Yablochny Spas.


Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1684 ◽  
Author(s):  
Katharina Willim ◽  
Melissa Stiers ◽  
Peter Annighöfer ◽  
Christian Ammer ◽  
Martin Ehbrecht ◽  
...  

Understory vegetation influences several ecosystem services and functions of European beech (Fagus sylvatica L.) forests. Despite this knowledge on the importance of understory vegetation, it is still difficult to measure its three-dimensional characteristics in a quantitative manner. With the recent advancements in terrestrial laser scanning (TLS), we now have the means to analyze detailed spatial patterns of forests. Here, we present a new measure to quantify understory complexity. We tested the approach for different management types, ranging from traditionally and alternatively managed forests and national parks in Germany to primary forests of Eastern Europe and the Ukraine, as well as on an inventory site with more detailed understory reference data. The understory complexity index (UCI) was derived from point clouds from single scans and tested for its relationship with forest management and conventional inventory data. Our results show that advanced tree regeneration is a strong driver of the UCI. Furthermore, the newly developed index successfully measured understory complexity of differently managed beech stands and was able to distinguish scanning positions located on and away from skid-trails in managed stands. The approach enables a deeper understanding of the complexity of understory structures of forests and their drivers and dependents.


2020 ◽  
Vol 12 (10) ◽  
pp. 1647 ◽  
Author(s):  
Dan Wu ◽  
Kasper Johansen ◽  
Stuart Phinn ◽  
Andrew Robson

Airborne Laser Scanning (ALS) and Terrestrial Laser Scanning (TLS) systems are useful tools for deriving horticultural tree structure estimates. However, there are limited studies to guide growers and agronomists on different applications of the two technologies for horticultural tree crops, despite the importance of measuring tree structure for pruning practices, yield forecasting, tree condition assessment, irrigation and fertilization optimization. Here, we evaluated ALS data against near coincident TLS data in avocado, macadamia and mango orchards to demonstrate and assess their accuracies and potential application for mapping crown area, fractional cover, maximum crown height, and crown volume. ALS and TLS measurements were similar for crown area, fractional cover and maximum crown height (coefficient of determination (R2) ≥ 0.94, relative root mean square error (rRMSE) ≤ 4.47%). Due to the limited ability of ALS data to measure lower branches and within crown structure, crown volume estimates from ALS and TLS data were less correlated (R2 = 0.81, rRMSE = 42.66%) with the ALS data found to consistently underestimate crown volume. To illustrate the effects of different spatial resolution, capacity and coverage of ALS and TLS data, we also calculated leaf area, leaf area density and vertical leaf area profile from the TLS data, while canopy height, tree row dimensions and tree counts) at the orchard level were calculated from ALS data. Our results showed that ALS data have the ability to accurately measure horticultural crown structural parameters, which mainly rely on top of crown information, and measurements of hedgerow width, length and tree counts at the orchard scale is also achievable. While the use of TLS data to map crown structure can only cover a limited number of trees, the assessment of all crown strata is achievable, allowing measurements of crown volume, leaf area density and vertical leaf area profile to be derived for individual trees. This study provides information for growers and horticultural industries on the capacities and achievable mapping accuracies of standard ALS data for calculating crown structural attributes of horticultural tree crops.


2011 ◽  
Vol 162 (6) ◽  
pp. 186-194 ◽  
Author(s):  
Hans Pretzsch ◽  
Stefan Seifert ◽  
Peng Huang

This paper addresses the potential of terrestrial laser scanning (TLS) for describing and modelling of tree crown structure and dynamics. We first present a general approach for the metabolic and structural scaling of tree crowns. Out of this approach we emphasize those normalization and scaling parameters which become accessible by TLS. For example we show how the individual tree leaf area index, convex hull, and its space-filling by leaves can be extracted out of laser scan data. This contributes to a theoretical and empirical substantiation of crown structure models which were missing so far for e.g. quantification of structural and species diversity in forest stands, inventory of crown biomass, species detection by remote sensing, and understanding of self- and alien-thinning in pure and mixed stands. Up to now works on this topic delivered a rather scattered empirical knowledge mainly by single inventories of trees and stands. In contrast, we recommend to start with a model approach, and to complete existing data with repeated TLS inventories in order to come to a consistent and theoretically based model of tree crowns.


2016 ◽  
Vol 27 (3-4) ◽  
pp. 5-15
Author(s):  
S. Kvesić ◽  
D. Ballian ◽  
T. V. Parpan

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. 


2017 ◽  
Vol 405 ◽  
pp. 381-390 ◽  
Author(s):  
Ignacio Barbeito ◽  
Mathieu Dassot ◽  
Dominik Bayer ◽  
Catherine Collet ◽  
Lars Drössler ◽  
...  

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