Influence of initial plant density on sawn timber properties for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)

Rais, Andreas; Poschenrieder, Werner; Pretzsch, Hans; Kuilen, J.W.G. van de

doi:10.1007/s13595-014-0362-8

Cited by 46 publications

(36 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is consistent with other studies that examined influence of planting density on structural timber properties [10,12,20,21]. Results suggest better prediction of Ex-ray by Edyn, undried with the increase of planting density.…”

Section: Discussionsupporting

confidence: 91%

See 1 more Smart Citation

The influence of planting density on modulus of elasticity of structural timber from Irish-grown Sitka Spruce

Simic¹,

Gendvilas²,

O'Reilly³

et al. 2018

Int. J. DNE

View full text Add to dashboard Cite

As Europe moves towards more sustainable construction, there is an increasing demand for structural timber. The purpose of this research is to explore new forestry management strategies, which will produce an optimum balance of the quantity and quality of structural timber over a minimum period of time. The focus is on timber from Sitka spruce, which is the most important Irish commercial forest tree species. Planting density is an important factor affecting both structural timber quantity and quality. Trees with wider spacing get more light and grow faster, which affects annual ring width and knot size. These, in turn, affect the bending strength, modulus of elasticity and density of timber, which are the grade determining properties according to EN 338:2003. The current standard planting density in Ireland is 2500 stems/ha and the timber produced meets the requirements for the C16 strength class. For Irish-grown Sitka spruce timber, modulus of elasticity is the critical grade determining property, which dictates the strength class. This study has two aims, first to explore the possibilities of improving the strength class by increasing the planting density and second, to explore the possibility of keeping the same class while increasing the quantity of structural timber by reducing the planting density. The effects of different planting densities, ranging from 1550 to 3700 stems per hectare, on the structural properties of Sitka spruce timber originated from a forest in County Leitrim are examined. Overall, 72 trees were felled and cut into logs. Logs were non-destructively tested using acoustic tools and subsequently processed into structural timber. The timber boards were then tested using three different types of strength graders in order to examine the difference in timber modulus of elasticity between different planting densities. The results showed statistically significant effects of different planting densities on the variation in timber modulus of elasticity.

show abstract

Section: Discussionsupporting

confidence: 91%

“…[21], the influence of initial plant density on timber properties of 40-year-old Douglas fir in Bavaria, Germany was examined. Timber boards originated from three different planting densities: 1000 stems/ha, 2000 stems/ha and 4000 stems/ha were tested.…”

Section: Discussionmentioning

confidence: 99%

The influence of planting density on modulus of elasticity of structural timber from Irish-grown Sitka Spruce

Simic¹,

Gendvilas²,

O'Reilly³

et al. 2018

Int. J. DNE

View full text Add to dashboard Cite

show abstract

“…In addition, numerous studies have found positive associations between stand density and wood stiffness in a range of species (Lasserre et al 2009;Moore et al 2009;Watt et al 2011;Zhang et al 2006). This includes a recent study in Germany which showed that higher stiffness Douglas-fir timber is obtained from stands planted at higher initial densities (Rais et al 2014). Therefore, this result should be interpreted with caution and future work is required in New Zealand to establish robust relationships between timber stiffness values, wood density and knot size incorporating the full range of sites and provenances.…”

Section: Discussionmentioning

confidence: 91%

Modelling the variation in wood density of New Zealand-grown Douglas-fir

Kimberley

McKinley

Cown

et al. 2017

N.Z. j. of For. Sci.

View full text Add to dashboard Cite

Background: Wood density is an important property that affects the performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) timber. In order to develop strategies to achieve certain end-product outcomes, forest managers and wood processors require information on the variation in wood density across sites, among trees within a stand and within trees. Therefore, the aim of this study was to develop models explaining the variation in outerwood density among sites and among trees within a stand, and the radial and longitudinal variation of wood density within a tree. Methods: An extensive dataset was assembled containing wood density measurements from historical studies carried out over a period spanning more than 50 years. The dataset contained breast height outerwood density cores from approximately 10,800 individual trees sampled from 312 stands throughout New Zealand, pith-to-bark radial density profiles from 515 trees from 47 stands, and discs taken from multiple heights in 172 trees from 21 stands. Linear and non-linear mixed models were developed using these data to explain the variation in inter-and intra-tree variation in Douglas-fir wood density. Results: Breast height outerwood density was positively related to mean annual air temperature in stands planted after 1969. This relationship was less apparent in older North Island stands, possibly due to the confounding influences of genetic differences. After adjusting for age and temperature, wood density was also positively related to soil carbon (C) to nitrogen (N) ratio in South Island stands where data on soil C:N ratio were available. There was only a minimal effect of stand density on breast height outerwood density, and a weak negative relationship between wood density and tree diameter within a stand. Within a stem, wood density decreased over the first seven rings from the pith and gradually increased beyond ring ten, eventually stabilising by ring 30. Longitudinal variation in wood density exhibited a sigmoidal pattern, being fairly constant over most of the height but increasing in the lower stem and decreasing in the upper stem. Conclusions: The study has provided greater insight into the extent and drivers of variation in Douglas-fir wood density, particularly the relative contributions of site and silviculture. The models developed to explain these trends in wood density have been coupled together and linked to a growth and yield simulator which also predicts branching characteristics to estimate the impact of different factors, primarily site, on the wood density distribution of log product assortments. Further work is required to investigate the impacts of genetic and soil properties on wood density, which may improve our understanding of site-level variation in wood density.

show abstract

“…Measured strength had been taken from 998 centre boards and 936 side boards. Details are given in Rais et al (2014a).…”

Section: Parameterisation Datamentioning

confidence: 99%

“…A sample of non-future crop trees of DBH > 25 cm had been taken in winter 2010/2011 (Rais et al 2014a), i.e. given by planting density in parentheses 50 (1000 ha -1 ), 38 (2000 ha -1 ) and 16 (4000 ha -1 ) at site Favourable and 14 (1000 ha -1 ), 30 (2000 ha -1 ) and 16 (4000 ha -1 ) at site Dry.…”

Section: Model Evaluation On Measured Board Strengthmentioning

confidence: 99%

Modelling sawn timber volume and strength development at the individual tree level – essential model features by the example of Douglas fir

Poschenrieder¹,

Rais²,

Kuilen³

et al. 2016

Silva Fenn.

Self Cite

View full text Add to dashboard Cite

-W.G., Pretzsch H. (2016). Modelling sawn timber volume and strength development at the individual tree level -essential model features by the example of Douglas fir. Silva Fennica vol. 50 no. 1 article id 1393. 25 p. Highlights• An individual tree timber growth and quality model toolbox was designed.• It realistically predicts an increase of bending strength with planting density.• Prediction was shown to be based on consideration of essential intrinsic variables.• Height-diameter-allometry depending on planting density was effective.• Consideration of cambial age and knot area ratio was crucial. AbstractWe designed a streamlined timber growth and quality model that aims at the effect of stand management on the efficiency of wood resource use. Applying the R based module toolbox to experimental plots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) we analysed essential model features for reflecting the influence of planting density on board strength. The current version realistically predicted a significant increase of centre board bending strength at tree age 40 with initial stand density. Model performance gained clear advantage from a) parameterisation of height to diameter allometry as dependent on planting density b) consideration of cambial age and cross-sectional knot area in board strength computation. Crown shape was less decisive. The model produced a significant effect of planting density even after a whole rotation period of 70 years as well as a realistic spectrum of board bending strength.

show abstract

Influence of initial plant density on sawn timber properties for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)

Cited by 46 publications

References 33 publications

The influence of planting density on modulus of elasticity of structural timber from Irish-grown Sitka Spruce

The influence of planting density on modulus of elasticity of structural timber from Irish-grown Sitka Spruce

Modelling the variation in wood density of New Zealand-grown Douglas-fir

Modelling sawn timber volume and strength development at the individual tree level – essential model features by the example of Douglas fir

Contact Info

Product

Resources

About