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Articles containing the keyword 'Pinus radiata'

Category : Article

article id 7147, category Article

S. A. Wilde, J. G. Iyer. (1963). Effect of natural subirrigation on the uptake of nutrients by forest plantations. Acta Forestalia Fennica vol. 76 no. 7 article id 7147. https://doi.org/10.14214/aff.7147

Keywords: Pinus radiata; growth; fertility; forest site; ground water table; United States

Abstract | View details | Full text in PDF | Author Info

Result of a survey of soils supporting forest plantations in Wisconsin in the United States indicated a close correlation between the levels of fertility of non-phreatic, coarse-textured soils and the growth of red pine (Pinus resinosa Roezl) stands aged from 15 to 32. This relationship, however was not observed in plantations established on deep-gley soils, underlain at a depth of 3–9 fl by ground water.

The survey encountered 20 red pine plantations on soils underlain by a deep ground water table accessible to tree roots thorough their contact with gley horizon or with extended capillary fringe. The average growth of the stands was 80 cubic feet/acre (5.6 m³/ha) at the age of 22 years. Thus, mensuration analysis suggested that the soils are the choice grounds for forestry enterprise. However, the analysis of soil samples showed that in many instances the soils are extremely low in mineral colloids, organic matter and nutrients. Many of the sites would be regarded as critically deficient in nitrogen, phosphorus and potassium.

The following hypothesis are suggested to explain this discrepancy:

a) The moisture content of coarse-textured non-phreatic soils remain near the wilting point during a large apart of the growing season with subsequent reduction of transpiration and uptake of nutrients. If a capillary fringe provides a supply of water for the root system, trees may derive an adequate supply of salts and exchangeable ions from comparatively infertile substrata.

b) The suitably located ground water provides adequate aeration of the surface soil layers which is not impeded by capillary fringe, increasing activity of mycorrhiza, and a mycotrophic uptake of nutrients from unweathered minerals.

c) The above effects of natural subirrigation should change the concept of soil fertility based on mere chemical analysis. The time during which the roots are engaged in active absorption appears to be of equal importance as the concentration of nutrients in available form.

The PDF includes a summary in Finnish.

Wilde, E-mail: sw@mm.unknown
Iyer, E-mail: ji@mm.unknown

article id 7516, category Article

Euan G. Mason, A. Graham D. Whyte. (1997). Modelling initial survival and growth of radiata pine in New Zealand. Acta Forestalia Fennica no. 255 article id 7516. https://doi.org/10.14214/aff.7516

Keywords: Pinus radiata; New Zealand; growth modelling; young corps; radiata pine

Abstract | View details | Full text in PDF | Author Info

A sensitive framework has been developed for modelling young radiata pine (Pinus radiata D. Don) survival, its growth and size class distribution, from time of planting to age 5 or 6 years. The data and analysis refer to the Central North Island region of New Zealand. The survival function is derived from a Weibull probability density function, to reflect diminishing mortality with the passage of time in young stands. An anamorphic family of trends was used, as very little between-tree competition can be expected in young stands. An exponential height function was found to fit best the lower portion of its sigmoid form. The most appropriate basal area/ha exponential function included an allometric adjustment which resulted in compatible mean height and basal area/ha models. Each of these equations successfully represented the effects of several establishment practices by making coefficients linear functions of site factors, management activities and their interactions. Height and diameter distribution modelling techniques that ensured compatibility with stand values were employed to represent the effects of management practices on crop variation. Model parameters for this research were estimated using data from site preparation experiments in the region and were tested with some independent data sets.

Mason, E-mail: em@mm.unknown
Whyte, E-mail: aw@mm.unknown

Category : Research article

article id 901, category Research article

Luis A. Apiolaza, Rosa M. Alzamora. (2013). Building deployment portfolios for genotypes under performance instability. Silva Fennica vol. 47 no. 1 article id 901. https://doi.org/10.14214/sf.901

Keywords: Pinus radiata; wood quality; breeding objectives; clonal portfolio; deployment portfolio; genotype by environment interaction

Abstract | Full text in HTML | Full text in PDF | Author Info

We used portfolio theory to analyze the tradeoffs between returns and performance instability of deployment units for Pinus radiata D. Don. We considered three groups of 34 trees each grown to produce appearance lumber, structural lumber, or both. Risk was based on the variability of tree returns in scenarios of changing volume, wood stiffness and presence of resin defects due to genotype by environment interaction inducing both changes of scale and differential tree response to environmental scenarios. The return of structural trees was highly variable with a mean of 3.11 NZ $/stem/year, followed by appearance-structural trees (3.48 NZ $/stem/year). In contrast, appearance trees had the lowest returns (1.99 NZ $/stem/year) and variability. The portfolio model selected structural trees in high-risk scenarios, but selection was apportioned between structural and appearance-structural trees as the risk decreased. The model selected only appearance trees for high-risk aversion. The analysis also considered silvicultural regimes, where the appearance-structural regime was selected under high variability. As risk decreased the appearance grades regime was also selected. The structural regime was rarely selected due to the variability of stiffness between trees. Using genotypes improved for stiffness could increase the expected value and reduce variability for structural purposes, making the structural regime more appealing.

Apiolaza, School of Forestry, University of Canterbury, Private Bag 4800, 8042 Canterbury, New Zealand E-mail: luis.apiolaza@canterbury.ac.nz
Alzamora, Instituto de Manejo Forestal, Universidad Austral, Valdivia, Chile E-mail: ralzamor@uach.cl

article id 42, category Research article

Pablo Martínez-Álvarez, Fernando Manuel Alves-Santos, Julio Javier Diez. (2012). In vitro and in vivo interactions between Trichoderma viride and Fusarium circinatum. Silva Fennica vol. 46 no. 3 article id 42. https://doi.org/10.14214/sf.42

Keywords: pitch canker; antagonism; biocontrol; biological control agents; endophytes; Pinus radiata; Spain

Abstract | View details | Full text in PDF | Author Info

Fusarium circinatum, a fungus that causes pitch canker disease, has been present in Europe since at least 2003, when it was detected in northern Spain and found to be producing severe damage in tree nurseries and pine plantations. In this study, we tested a method of biological control of the disease with Trichoderma viride, a fungal species successfully used against many other pathogens. In vitro and in vivo assays were carried out to test the efficacy of this antagonist in controlling F. circinatum. The T. viride isolate exerted a significant effect on the growth of F. circinatum in the in vitro assay, reducing the length of the pathogen colony by half. However, although we tested three different concentrations of the T. viride spore solution, no clear conclusions were obtained with regard to the effects on the Pinus radiata seedlings. To our knowledge, this is the first study carried out with the aim of using Trichoderma spp. to control pitch canker disease.

Martínez-Álvarez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain E-mail: pmtnez@pvs.uva.es
Alves-Santos, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain E-mail: fmas@nn.es
Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain E-mail: jjd@nn.es

article id 212, category Research article

Sandhya Samarasinghe. (2009). Exploration of fracture dynamics properties and predicting fracture toughness of individual wood beams using neural networks. Silva Fennica vol. 43 no. 2 article id 212. https://doi.org/10.14214/sf.212

Keywords: Pinus radiata; wood properties; cracks; initiation; New Zealand; peak stress; speed; video imaging

Abstract | View details | Full text in PDF | Author Info

In this study, the time to crack initiation (T_init), duration of crack propagation (T_frac), crack initiation stress, peak stress as well as crack speed and fracture toughness were investigated for three Rates of Loading (ROL) and four sizes of notched wood beams using high-speed video imaging and neural networks. T_init was consistent for all volumes and the average T_init was nonlinearly related to volume and ROL. For the smallest ROL, there was a distinct volume effect on T_init and the effect was negligble at the largest ROL. However, the stress at crack initiation was not consistent. Contrasting these, T_frac for all volumes appeared to be highly variable but the peak stress carried prior to catastrophic failure was consistent. The crack propagation was a wave phenomenon with positive and negative (crack closure) speeds that varied with the ROL. As accurate estimation of crack initiation load (or stress) and its relationship to peak load (or stress) is important for determining fracture toughness, Artificial Neural Networks (ANN) models were developed for predicting them from volume, Young’s modulus, face and grain angles, density, moisture content and ROL. Models for crack initiation load and peak load showed much higher predictive power than those for the stresses with correlation coefficients of 0.85 and 0.97, respectively, between the actual and predicted loads. Neural networks were also developed for predicting fracture toughness of individual wood specimens and the best model produced a statistically significant correlation of 0.813 between the predicted and actual fracture toughness on a validation dataset. The inputs captured 62% of variability of fracture toughness. Volume and Young’s modulus were the top two contributing variables with others providing lesser contributions.

Samarasinghe, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand E-mail: sandhya.samarasinghe@lincoln.ac.nz

article id 221, category Research article

Glen Murphy, Rod Brownlie, Mark Kimberley, Peter Beets. (2009). Impacts of forest harvesting related soil disturbance on end-of-rotation wood quality and quantity in a New Zealand radiata pine forest. Silva Fennica vol. 43 no. 1 article id 221. https://doi.org/10.14214/sf.221

Keywords: Pinus radiata; harvesting; compaction; wood density; tree growth; stiffness; litter removal; nitrogen deficiency

Abstract | View details | Full text in PDF | Author Info

The long-term effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on wood quality and quantity of second-rotation Pinus radiata growing on a clay loam soil, was assessed at the end the rotation, 26 years after planting. Relative to Control plots, average tree and stand total volume at rotation end was not significantly affected by litter removal and nil or light compaction, but was significantly reduced by 28% by litter and topsoil removal and moderate subsoil compaction, and further reduced by 38% by heavy compaction. Wood density at breast height in the inner rings of trees in the most disturbed treatments was elevated by up to 30 kg m^–3. This occurred because these treatments were more N deficient as reflected by foliar N levels during the first 11 years of growth relative to the Control. However, no treatment differences in wood density were evident in outer rings, and by rotation age overall mean density did not differ significantly between treatments. Neither acoustic velocity of standing trees, nor acoustic velocity of logs, was significantly affected by soil disturbance, indicating that stiffness of lumber cut from trees in the trial was likely to be similar for all treatments. Economic impacts of soil disturbance and compaction on this soil type will therefore result largely from the considerable negative impacts on final tree size, with little or no compensation from improved wood properties.

Murphy, Forest Engineering, Resources and Management Department, Oregon State University, Corvallis, Oregon, USA E-mail: glen.murphy@oregonstate.edu
Brownlie, Scion Research, Rotorua, New Zealand E-mail: rb@nn.nz
Kimberley, Scion Research, Rotorua, New Zealand E-mail: mk@nn.nz
Beets, Scion Research, Rotorua, New Zealand E-mail: pb@nn.nz

article id 309, category Research article

Sandhya Samarasinghe, Don Kulasiri, Tristan Jamieson. (2007). Neural networks for predicting fracture toughness of individual wood samples. Silva Fennica vol. 41 no. 1 article id 309. https://doi.org/10.14214/sf.309

Keywords: Pinus radiata; New Zealand; video imaging; strain energy release rate; Neural Networks; fracture toughness

Abstract | View details | Full text in PDF | Author Info

Strain energy release rate (G_Ic) of Pinus radiata in the TL opening mode was determined using the compliance crack length relationship. A total of 123 specimens consisting of four sizes of specimen with each size having four different crack lengths were tested. For each specimen, grain and ring angles, density and moisture content were measured. Video imaging, was used to measure crack length during propagation. Since cracks extended in stages, full compliance-crack length relationship was developed for each specimen based on their initial and subsequent crack lengths. No significant differences in G_Ic, between initial and subsequent crack lengths were found for the smaller specimens by paired sample t-tests, but differences were significant for the largest specimen size. The Average fracture toughness was calculated from G_Ic and it was 215 kPa.m^0.5. Three artificial neural networks were developed to predict the: 1) force required to propagate a crack, 2) crack extension, and 3) fracture toughness of an individual specimen. Each was successful, producing respective R² of 0.870, 0.865, and 0.621 on validation data. A sensitivity analysis of the networks revealed that the crack length was the most influential with 21% contribution followed by grain angle with 14% contribution for predicting the applied force. This was followed by volume and physical properties. For predicting the crack extension, density had the greatest contribution (20%) followed by previous crack length and force contributing 16% equally. Fracture toughness was dominated by the dimensional parameters of the specimen contributing (42%) followed by anisotropy and physical properties.

Samarasinghe, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, New Zealand E-mail: ss@nn.nz
Kulasiri, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, New Zealand E-mail: dk@nn.nz
Jamieson, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, New Zealand E-mail: tj@nn.nz

article id 416, category Research article

Glen Murphy, John G. Firth, Malcolm F. Skinner. (2004). Long-term impacts of forest harvesting related soil disturbance on log product yields and economic potential in a New Zealand forest. Silva Fennica vol. 38 no. 3 article id 416. https://doi.org/10.14214/sf.416

Keywords: Pinus radiata; harvesting; compaction; tree growth; litter removal

Abstract | View details | Full text in PDF | Author Info

The effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on the productivity, log product yields and economic potential of second-rotation Pinus radiata growing on a clay loam soil, was assessed in a long-term trial 21 years after planting. The results are projected forward to the expected harvest age of 28 years. Relative to control plots, average tree volume at 21 years was reduced by 8% in the plots where the litter had been removed and the topsoil had been compacted, and by up to 42% in the plots where the topsoil had been removed and the subsoil compacted. The “degree of compaction” did not have a significant effect on average tree volume in the plots where litter had been removed but did have a significant effect where the topsoil had been removed. Per tree economic potential was reduced to a greater extent (up to 60% loss in value) than average tree volume was reduced. This was largely due to changes in log product yield distribution. Projecting tree growth forward to the end of the rotation at age 28 indicated that the impacts of soil disturbance on tree growth, economic potential and log product yields are likely to be similar in relative terms to those found at age 21.

Murphy, Forest Engineering Department, Oregon State University, Corvallis, OR 97331, USA E-mail: glen.murphy@orst.edu
Firth, Forest Research, Sala Street, Rotorua, New Zealand E-mail: jgf@nn.nz
Skinner, Forest Research, Sala Street, Rotorua, New Zealand E-mail: mfs@nn.nz

article id 415, category Research article

Sandhya Samarasinghe, Don Kulasiri. (2004). Stress intensity factor of wood from crack-tip displacement fields obtained from digital image processing. Silva Fennica vol. 38 no. 3 article id 415. https://doi.org/10.14214/sf.415

Keywords: Pinus radiata; wood; fracture toughness; stress intensity factor; digital image correlation; orthotropic fracture theory

Abstract | View details | Full text in PDF | Author Info

Stress intensity factor of radiata pine (Pinus radiata) in Tangential-Longitudinal opening mode was determined from crack-tip displacement fields obtained from digital image correlation in conjunction with orthotropic fracture theory. For lower loads, experiments agreed with the linear elastic fracture theory but for higher loads, stress intensity factor and load relationship was nonlinear. For 41% of the specimens tested, tip-displacement based stress intensity factor agreed with that based on the ASTM standard formula for lower loads but deviated for higher loads closer to failure. The tip displacement plots showed that the nonlinear behaviour is due to large displacements which we attributed to large plastic deformations and/or micro-cracking in this region. The other 59% specimens showed a similar trend except that the crack-tip based stress intensity factor was consistently higher than the value obtained from the standard formula. The fracture toughness from tip displacements was larger than the standard values for all specimens and the two were related by a logarithmic function with an R2 of 0.61. The study also established that fracture toughness increases with the angle of inclination of the original crack plane to the Radial Longitudinal plane.

Samarasinghe, Lincoln University, P.O. Box 84, Canterbury, New Zealand E-mail: ss@nn.nz
Kulasiri, Lincoln University, P.O. Box 84, Canterbury, New Zealand E-mail: kulasird@lincoln.ac.nz

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