scholarly journals Predicting Douglas-fir knot size in the stand: a random forest model based on CT and field measurements

2021 ◽  
Author(s):  
Bruna L. Longo ◽  
Franka Brüchert ◽  
Gero Becker ◽  
Udo H. Sauter
Keyword(s):  
Random Forest ◽  
Wood Quality ◽  
Field Measurements ◽  
Detection Algorithm ◽  
Douglas Fir ◽  
Internal Quality ◽  
Internal Diameter ◽  
Branch Diameter ◽  
Standing Trees ◽  
Ct Technology

AbstractBranches are not only of vital importance to tree physiology and growth but are also one of the most influential features in wood quality. To improve the availability of data throughout the forest-to-industry production, information on internal quality (e.g. knots) of both felled and standing trees in the forest would be desirable. This study presents models for predicting the internal knot diameter of Douglas-fir logs based on characteristics measured in the field. The data were composed of 87 trees (aged from 32 to 78 years), collected from six trial sites in southwest Germany, and cut into 4–5 m logs on-site. The internal knot diameter was obtained by applying a knot detection algorithm to the CT images of the logs. Applying the Random Forest (RF) technique, two models were developed: (1) MBD: to predict the branch diameter (BD) at different radial positions within the stem, and (2) MBDmax: to predict the maximum internal branch diameter (BDmax). Both models presented a good performance, predicting BD with an RMSE of 4.26 mm (R2 = 0.84) and BDmax with an RMSE of 5.65 mm (R2 = 0.78). In this context, the innovative combination of CT technology and RF modelling technique showed promising potential to be used in future investigations, as it provided a good performance while being flexible in terms of input data structure and also allowing the inclusion of otherwise underexplored databases. This study showed a possibility to predict the internal diameter of branches from field measurements, introducing an advance towards connecting forest and sawmill.

Clear wood content in standing trees predicted from branch scar measurements with terrestrial LiDAR and verified with X-ray computed tomography

2014 ◽  
Vol 44 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Stefan M. Stängle ◽  
Franka Brüchert ◽  
Ursula Kretschmer ◽  
Heinrich Spiecker ◽  
Udo H. Sauter
Keyword(s):  
Computed Tomography ◽  
Wood Quality ◽  
European Beech ◽  
Internal Quality ◽  
Clear Wood ◽  
Terrestrial Lidar ◽  
X Ray ◽  
Standing Trees ◽  
X Ray Computed

Knowledge about the wood quality of standing trees is crucial in that it serves as an excellent means for nearly all stages of the wood-supply chain. Better information about internal wood characteristics can be derived from the outside appearance by establishing a correlation between the bark characteristics of a stem and its internal quality. This paper presents an approach where the quality determination of standing trees using a terrestrial light detection and ranging (LiDAR) system is combined with the information about internal quality of logs using X-ray computed tomography (CT). Results show a high accuracy for branch scar measurements with terrestrial LiDAR and knot measurement with CT. A strong correlation between scar seal quotient and the amount of clear wood could be confirmed using European beech (Fagus sylvatica L.) as an example. Quality grading of virtually segmented logs using terrestrial LiDAR and CT showed moderate correlation; 62.5% of the segments were allocated to the same grade by both approaches. In conclusion, terrestrial LiDAR in forest inventory could be used as an instrument to predict inner wood quality in greater detail by gathering data on the outer appearance and branch scars of standing trees. This additional knowledge has the potential to improve forest planning, bucking instructions, and a roundwood allocation that meets industry demand.

Auswirkungen der Wertastung auf das Douglasien-Wachstum: Ergebnisse aus Nordwestdeutschland

2019 ◽  
Vol 170 (4) ◽  
pp. 207-215
Author(s):  
Andreas Weller
Keyword(s):  
Wood Quality ◽  
Tree Height ◽  
Douglas Fir ◽  
Control Group ◽  
Radial Increment ◽  
Lower Saxony ◽  
Branch Diameter ◽  
Stem Taper ◽  
Positive Effect ◽  
Forest District

Effects of pruning on the growth of Douglas-fir: findings from northwestern Germany Owing to Douglas-firs' insufficient self-pruning ability, for the production of high-grade wood, manual pruning is mandatory. Pruning of live branches increases the branch-free tree volume considerably. Branchiness is important for grading wood quality, but with pruning this detrimental characteristic loses its significance for the value of the Douglas-fir asset. In 1980, trials were conducted in the forest district of Ahlhorn (Lower Saxony, Germany) with three-year-old Douglas- firs to test the effects of live pruning on tree growth. The sample material consists of 93 trees which were periodically pruned beginning from a height of 6 to 8 m up to 20, 40 and 60% of tree height, as well as of 9 Douglas-firs of the unpruned control group. However, only specimens with a pruning height of 60% had live branches removed at each pruning. By means of a multivariate linear regression model the effects of pruning on the dependent variates diameter at breast height (dbh), tree height, stem taper of the butt log and maximum branch diameter approximately at a whorl's height of 5 m were studied up to the age of 39 years. Pruning of live branches had a significant effect on periodic radial growth as well as on bottom log allocation, though not on tree height or branch diameter. Live prune led to moderate reduction of radial increment and had a positive effect on stem taper. The results of the study largely agree with earlier studies on the effects of pruning on Douglas-fir growth.

Determination of relative economic weights for multitrait selection in coastal Douglas-fir

1998 ◽  
Vol 28 (8) ◽  
pp. 1164-1170 ◽  
Author(s):  
Carol A Aubry ◽  
W T Adams ◽  
Thomas D Fahey
Keyword(s):  
Wood Density ◽  
Wood Quality ◽  
Tree Height ◽  
Douglas Fir ◽  
Stem Volume ◽  
Branch Diameter ◽  
Economic Weights ◽  
Selection Indices ◽  
Multitrait Selection

Relationships between tree traits and tree value for lumber production were investigated. For the purposes of estimating relative economic weights for use in multitrait selection in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), tree height, diameter at breast height, and branch diameter were measured on 164 trees (ages 36-66 years). Increment cores from a subsample (92) of these trees were assayed by X-ray densitometry to determine wood density. Bole volume was derived by summing the log volumes of all logs from each tree. Value of lumber recovered from each tree was determined in a separate mill study using both visual and machine stress rated (MSR) grading rules. Multiple linear regression was used to relate tree value to the growth and wood quality traits. Stem volume and branch diameter significantly influenced tree value under visual grading, with relative economic weights of 0.06dm3 and -5.22cm, respectively. Wood density significantly influenced tree value under MSR grading (relative economic weights: 0.06dm3, -6.69cm, and 0.06kg/mdm3, respectively), where lumber strength is measured more accurately. These regression coefficients can be used directly as economic weights in selection indices.

Wachstum und Wertleistung der Douglasie in Abhängigkeit von der Standraumgestaltung

2012 ◽  
Vol 163 (3) ◽  
pp. 96-104 ◽  
Author(s):  
Joachim Klädtke ◽  
Ulrich Kohnle ◽  
Edgar Kublin ◽  
Andreas Ehring ◽  
Hans Pretzsch ◽  
...  
Keyword(s):  
Wood Quality ◽  
Volume Growth ◽  
Static Stability ◽  
Douglas Fir ◽  
Breast Height ◽  
Monetary Analysis ◽  
Starting Conditions ◽  
Tree Number ◽  
Clear Differentiation ◽  
Further Development

Growth and value production of Douglas-fir under varying stand densities The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with 500, 1,000, 2,000 and 4,000 Douglas-firs per hectare. The treatment was performed according to a standardized experiment program. The results show that at low initial tree numbers, the diameter on breast height (DBH) of (pre)dominant trees at the beginning of the observations (with 12 m top height) is bigger than at higher initial plant numbers. Accordingly, the quotient of height (H) to DBH (as an indicator for tree's static stability) is lower. The further development of DBH and H/DBH quotient is decisively determined by stand treatment, which superimposes the effect of the initial tree number. The total volume growth shows a clear differentiation, too, the variants with initially high tree numbers appearing on top. In the monetary analysis, this ranking is reversed: despite a supposed inferior wood quality, the variants with lower initial tree numbers clearly outperform the ones with higher numbers in terms of value. From these results, the following silvicultural recommendations for Douglas-fir can be derived: the initial tree numbers should be in the range from 1,000 to 2,000 plants per hectare. On technically not accessible sites, even lower tree numbers may come into question. The strong influence of stand treatment on DBH and H/DBH development highlights the problem of postponed thinnings, for this causes growth and stability losses even under favorable starting conditions in terms of competition.

scholarly journals Non-Destructive Assessment of Wood Stiffness in Scots Pine (Pinus sylvestris L.) and its Use in Forest Tree Improvement

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 491 ◽  
Author(s):  
Irena Fundova ◽  
Tomas Funda ◽  
Harry X. Wu
Keyword(s):  
Scots Pine ◽  
Growth Traits ◽  
Wood Quality ◽  
Genetic Correlations ◽  
Forest Tree ◽  
Wood Stiffness ◽  
Standing Trees ◽  
Genetic And Phenotypic Correlations ◽  
Sib Families ◽  
Using Data

Wood stiffness is an important wood mechanical property that predetermines the suitability of sawn timber for construction purposes. Negative genetic correlations between wood stiffness and growth traits have, however, been reported for many conifer species including Scots pine. It is, therefore, important that breeding programs consider wood stiffness and growth traits simultaneously. The study aims to (1) evaluate different approaches of calculating the dynamic modulus of elasticity (MOE, non-destructively assessed stiffness) using data from X-ray analysis (SilviScan) as a benchmark, (2) estimate genetic parameters, and (3) apply index selection. In total, we non-destructively measured 622 standing trees from 175 full-sib families for acoustic velocity (VEL) using Hitman and for wood density (DEN) using Resistograph and Pilodyn. We combined VEL with different wood densities, raw (DENRES) and adjusted (DENRES.TB) Resistograph density, Pilodyn density measured with (DENPIL) and without bark (DENPIL.B), constant of 1000 kg·m−3 (DENCONST), and SilviScan density (DENSILV), to calculate MOEs and compare them with the benchmark SilviScan MOE (MOESILV). We also derived Smith–Hazel indices for simultaneous improvement of stem diameter (DBH) and wood stiffness. The highest additive genetic and phenotypic correlations of the benchmark MOESILV with the alternative MOE measures (tested) were attained by MOEDENSILV (0.95 and 0.75, respectively) and were closely followed by MOEDENRES.TB (0.91 and 0.70, respectively) and MOEDENCONST and VEL (0.91 and 0.65, respectively for both). Correlations with MOEDENPIL, MOEDENPIL.B, and MOEDENRES were lower. Narrow-sense heritabilities were moderate, ranging from 0.39 (MOESILV) to 0.46 (MOEDENSILV). All indices revealed an opportunity for joint improvement of DBH and MOE. Conclusions: MOEDENRES.TB appears to be the most efficient approach for indirect selection for wood stiffness in Scots pine, although VEL alone and MOEDENCONST have provided very good results too. An index combining DBH and MOEDENRES.TB seems to offer the best compromise for simultaneous improvement of growth, fiber, and wood quality traits.

Heritability and phenotypic and genetic correlations of coastal Douglas-fir (Pseudotsuga menziesii) wood quality traits

2008 ◽  
Vol 38 (6) ◽  
pp. 1536-1546 ◽  
Author(s):  
Nicholas K. Ukrainetz ◽  
Kyu-Young Kang ◽  
Sally N. Aitken ◽  
Michael Stoehr ◽  
Shawn D. Mansfield
Keyword(s):  
Cell Wall ◽  
Genetic Control ◽  
Pseudotsuga Menziesii ◽  
Wood Quality ◽  
Genetic Correlations ◽  
Douglas Fir ◽  
Correlated Response ◽  
Sample Population ◽  
Quality Traits ◽  
Glucose Content

Genetic control and relationships among coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) growth and wood quality traits were assessed by estimating heritability and phenotypic and genetic correlations using 600 trees representing 15 full-sib families sampled from four progeny test sites. Heritability estimates ranged from 0.23 to 0.30 for growth traits, 0.19 for fibre coarseness, from 0.21 to 0.54 for wood density, from 0.16 to 0.97 for cell wall carbohydrates, and 0.79 and 0.91 for lignin content at two sites, Squamish River and Gold River, respectively. Glucose content, indicative of cell wall cellulose composition, and lignin were shown to be under strong genetic control, whereas fibre coarseness was shown to be under weak genetic control. Phenotypic correlations revealed that larger trees generally have longer fibres with higher fibre coarseness, lower density, lower carbohydrate content, a greater proportion of cell wall lignin, and higher microfibril angle. Genetic correlations and correlated response to selection suggest that breeding for height growth would result in a reduction in wood quality, whereas breeding for improved earlywood density in Douglas-fir would result in negligible reductions in volume and appears to be an ideal target for selecting for improved wood quality (density) while maintaining growth in the sample population.

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