Wettability of Sitka spruce timber stored in a Scottish sawmill yard

Kiln-dried and air-dried Sitka spruce battens were exposed to outdoor weathering within stickered, close packed and wrapped packs and at the upper surface of these packs. A four-week exposure period was used in James Jones and Sons Ltd. sawmill yard near Aboyne, NE Scotland. The wettability of batten samples removed from the packs of timber was determined by a drop contact angle method using a video tape technique. Timber exposed to air drying before weathering in the experimental packs generally had a greater wettability than kiln-dried timber at the end of the exposure period. However, kiln-dried timber stored in stickered packs developed a greater wettability than similarly stored air-dried timber, suggesting that the kiln drying process increased the susceptibility of timber to developing increased wettability. Close-packed timber protected from sunlight and rain water, by covering the upper surface of the pack with microporous plastic sheeting, maintained a lower wettability than unprotected close-packed or stickered timber. Fungal spoilage was unlikely to develop on timber stored in pack types which developed high timber wettability, the storage conditions leading to an increase in wettability were adverse to fungal development. Kiln-dried timber stored in stickered packs in the sawmill yard may become particularly vulnerable to fungal attack if subsequently exposed to damp conditions in service. Received 15 October 1998     

Effects of early re-spacing on the physical and mechanical properties of Sitka spruce structural timber

The effects of early re-spacing on the physical and mechanical properties of Sitka spruce (Picea sitchensis [Bong.] Carr.) structural-dimensioned timber were studied using material from a fully replicated 57-year-old trial located in Northern Ireland, which had been thinned at age 11 years. Basic density, distortion (spring, twist and bow), modulus of elasticity (MOE) and modulus of rupture (MOR) in bending of structural timber from four different re-spacing treatments (1.83 m × 3.66 m, 3.66 m × 3.66 m, 3.66 m × 5.49 m and 5.49 m × 5.49 m) were compared with those of timber from a control (1.83 m × 1.83 m). Re-spacing intensity had a significant effect on both modulus of elasticity (p = 0.006) and modulus of rupture (p = 0.009), but not on basic density (p = 0.379) or distortion (p > 0.200). Timber from the two widest re-spacing treatments failed to meet the requirements for the C14 strength class, while timber from the control met the requirements for the C16 strength class. Both MOE and MOR were significantly and negatively associated with knot size and frequency, which in turn increased with re-spacing intensity. Overall, re-spacing intensity only explained approximately 10% of the total amount of variation in both MOE and MOR, with most of the variation due to inter- and intra-tree differences within a treatment. Based on these results, re-spacing of Sitka spruce to a residual stand density of less than 900 trees/ha (3.33 m × 3.33 m) is not recommended if the goal of management is to produce C16 structural timber.     

Microbial Inoculants for Sustainable Forests

Abstract

Fungal root pathogens are widespread and may cause substantial seedling losses in conifer nurseries. Furthermore, poor seedling survival and growth on reforestation sites results in reduced forest regeneration. Use of microbial inoculants for disease control and plant growth promotion has become an important endeavour. A microbial culture collection of 500 strains was assessed for biological control of fungal root pathogens and/or plant growth promotion of conifer seedlings. Seven of these strains showed significant suppres-sive effects on various soil-bome fungal pathogens. On Douglas fir, two strains, RAL3 and 64-3, reduced disease caused by Fusariumby. 7-42% in repeated growth room assays. The same strains significantly increased healthy stand of white spruce seedlings inoculated with Fusariumand Pythiumin a conifer nursery, and increased the survival of bare-root white spruce seedlings planted on a reforestation site by 19-23%. Both strains also significantly increased new root and total plant dry weights. Strain RAL3 in commercial formulation maintained a viable population of about log 8-9 cfu/ml for over a year when stored at 5°C. Strain survival on seed varied with conifer species. No decreases in bacterial populations were observed on seeds of jack pine or Douglas fir after 37 to 44 days storage at 5°C, but decreases were observed on seeds of white spruce and Scots pine. This study has provided candidate beneficial microbial inocu-lants which offer promise for development of commercial inoculants for the forestry industry.     

Producing softwood of different quality: does this provide risk compensation?

This study analysed whether the production of high-quality assortments, saw timber and pulpwood in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) stands leads to effects of risk compensation. Mixtures of conventionally treated pruned and non-pruned stands, as well as mixtures of stands which had been optimized concerning the occurrence of assortments and financial criteria were considered. The price simulation was done by bootstrapping to avoid the assumption of a certain distribution of timber prices, and to preserve the correlations of the timber prices from different assortments. The financial valuation was carried out with annuities within a Monte Carlo simulation with 10,000 repetitions. To quantify the effect of natural hazards, the calculations were repeated with and without this factor. Minimum risk portfolios were determined and optimization performed using both a utility function as well as the value-at-risk approach. The mixtures with minimum risk were dominated by pine stands, as they are less affected by natural hazards and prices for pine timber have a lower volatility, although pine timber prices are generally lower compared to that of spruce timber. These pine dominated portfolios showed risk reductions up to 92% compared to the riskiest single stand, but the annuities were reduced even more. In contrast to this, the portfolios optimized with the utility function and the value-at-risk approach consisted of spruce stands. These spruce portfolios showed an efficient risk reduction of up to 60%. Additionally, higher annuities and larger diversification effects occurred in the portfolios containing the optimized stands. Integrating the risk of natural hazards, the annuities decreased, as did the correlation of the annuities of the different stands, while risk increased. Altogether these effects led to higher relative risk reductions when forming optimal portfolios. These results indicate that producing different assortments of spruce and pine leads to risk compensation, especially when considering portfolios consisting of optimized stands.     

Timber Improvement: II. The Effect of Vigour on Young-Growth Sitka Spruce

A study of the effect of vigour on the within-ring componentsof young, plantation-grown Sitka spruce (Picea sitchensis (Bong.)Carr.) has been made as a contribution to a more effective selectionof timber having superior timber yields and to appraise thelikely effect of forest management practices which, by influencingvigour of growth, affect wood quality. It was found that as ring width in Sitka spruce increases:

1. Thereis an increase in early wood width without a correspondingincreasein late wood and so a greater proportion of early wood.
2. Thereis a reduction in the average density of the early woodcomponentof the rings.
3. Because of the combined effects of 1 and 2,there is a reductionin wood density as vigour of growth increases.
4. There is a lower minimum early wood density.

The significance of these observations on the growth and technicalperformance of Sitka spruce timber is considered. The possibility of appraising adult wood characteristics onthe basis of juvenile wood performance is examined and the scopefor assessing fibre length and density of adult wood from anexamination of wood laid down at about six years from the pithis demonstrated.     

Models for Assessing Timber Grade Distribution and Economic Value of Standing Birch Trees

In order to obtain a more precise prediction of the distribution of each timber grade or log grade with regard to the volume of birch (Betula pendula Roth., B. pubescens Ehrh.) in models for long-term planning, ordered probit models were developed. These models were developed by using data from three mixed birch and Norway spruce stands in Norway. The data consisted of 168 stems. In Norway, three ordinary birch saw log grades are commonly used, with pulpwood as a fourth grade. In this study, these four grades were applied in addition to waste timber, which was treated as a fifth grade. The developed models showed that the grade distribution of birch trees of mixed birch and spruce stands was highly correlated with tree height (p<0.01) and height to first visible dry branch (p=0.081). The statistical significance of both models was good (p<0.0001), as measured by log likelihood test statistics. Classifying the 168 stems by saw timber or pulpwood in butt log led to greatly improved estimates (p<0.01). The developed models would allow the incorporation of timber grade in stand simulators, enabling more precise predictions regarding the economic implications of alternative management strategies for birch trees.     

Effects of thinning and fertilization on wood properties and economic returns for Norway spruce

The effects of silviculture on wood and tracheid properties, and economic returns of Norway spruce (Picea abies (L.) Karst.) were investigated in two case studies, one comparing different thinning intensity in southeastern Finland and the other considering the effects of optimal nutrient addition in northern Sweden. Models for predicting the wood and tracheid properties of Norway spruce were integrated into a distance-independent process-based growth and yield model. Increasing the thinning intensity resulted in a lower mean wood density, tracheid length, and latewood proportion in harvested wood. Wood density and tracheid length of harvested pulpwood slightly decreased in later thinnings and final cuts. Thinning regimes with high early growing stock and decreasing later growing stock were most profitable. Nutrient addition accelerated volume growth and increased the value growth. The increase in volume growth due to nutrient addition more than offset the economic influence of the loss in wood density and tracheid length.     

Beziehungen zwischen der Ausbreitung künstlicher Fomes annosus-Infektionen in den Stämmchen zweier Fichtenklone und einigen holzchemischen Eigenschaften

The spread of Fomes annosus from artificial infections of stems, in relation to the chemical characteristics of timber of two spruce clones . Differences in the spread of Fomes annosus in two spruce clones (Picea abies Karst.), which were found by DIMITRI, may be attributed to differences in the properties of the wood from the two clones, detected in laboratory tests. Wood meal from the more resistant clone R inhibited Fomes annosus in bioassays more than wood meal from the more susceptible clone A. Wood from clne A-trees showed a higher nitrogen content than wood from clone R-trees.     

Influence of Log Characteristics on Drum Debarking of Pulpwood

Properties of 200 poorly debarked softwood logs were studied in order to examine how different log characteristics affect drum debarking of mixed pine (Pinus sylvestris L.) and spruce [Picea abies (L.) Karst] pulpwood during the summer. The definition of a poorly debarked log and the sampling criterion was that >10 dm² bark remained on the log surface. The average share of poorly debarked logs was 8% and the most frequent log type was breakage logs. The main species among the poorly debarked logs was spruce and the mean wood moisture content was considerably lower than for the pulpwood chips. Many logs were affected by root rot or were damaged by harvesting equipment, resulting in reduced moisture content and, consequently, in increased bark/wood shear strength. Bark from the poorly debarked logs contributed to approximately 68% of the bark content in the chips. By avoiding air-drying of pulpwood, or by sorting pulpwood prior to debarking, the bark content in chips might be substantially reduced, which would improve the purity of the pulp and decrease production costs.     

Effects of pre- and post-planting shading on growth of container Norway spruce seedlings

Norway spruce (Picea abies (L.) Karst.) is shade-tolerant and sensitive to high irradiance, summer frosts and winter desiccation, which can impair its reforestation success. In this study, artificial pre- and post-planting shading was examined to determine their effects on post-planting shoot and root growth as well as the vigor of one- and two-year-old Norway spruce seedlings. Three planting experiments were carried out on open nursery fields (Exp. 1, 2) and on a mounded forest clearcut in central Finland (Exp. 3). Before planting, the seedlings were stored over winter either in a freezer or on open fields under snow cover. For two weeks prior to planting, half of the seedlings were placed in the open and the other half under a horizontal shade netting (light transmittance 56 %) (Exp. 1, 2). All seedlings were planted with or without a vertical post-planting shade, which was located on the southern side. Post-planting shading enhanced shoot growth and reduced damage (better visual vigor and needle color and less pine-weevil damage) on Norway spruce seedlings for at least two years after planting (Exp. 2, 3). Those seedlings, that had been stored over winter in the open and kept in shade prior to planting seemed to benefit most from post-planting shading (Exp. 2). However, post-planting shading may give variable results, depending on the seedling quality and weather conditions after planting, and may even reduce shoot growth if no pre-planting shading is used (Exp. 1). Shoot growth may also be improved at the expense of root growth (Exp. 3). The costs of manufacturing and installing post-planting shades may limit their use in practice, for example, to selected regeneration sites where there is high risk of frost damage but where no alternative silvicultural procedure (shelterwood or nurse crop) has been used.     

Effects of rotation length on the grade recovery and wood properties of Sitka spruce structural timber grown in Great Britain

Context   

Rotation length is known to affect timber quality in many plantation species, but its effect on the properties of Sitka spruce (Picea sitchensis) structural timber has not been quantified.     

Artificial regeneration of Korean spruce in northeast China

Korean spruce (Picea koraiensis Nakai) has been included as a Chinese regeneration species since the 1960′s. In the 1970′s it became one of the four most important species in the northeast forest region of China. Korean spruce is a timber species with a wide range of adaptation, high survival rate, and few diseases or pests. Studies of 30-year trials show that the regeneration of korean spruce is successful and has a prospective future.     

Growth and enzyme production by Bacillus subtilis and Flavobacterium pectinovorum in Picea sitchensis

Summary When Sitka spruce (Picea sitchensis) is stored in water, an increase takes place in the permeability of the wood. This increase is due to bacterial degradation of the tori and bordered pit membranes and partial degradation of the crossfield pits. It has been demonstrated that two bacteria—Bacillus subtilis and Flavobacterium pectinovorum—isolated from this water stored wood, grow and produce amylase, xylanase and pectinase in sapwood blocks suspended in sterile pond water. Since these organisms have also been shown to increase the permeability of sapwood blocks, it has been concluded that they are primarily responsible for the permeability changes that occur when spruce poles are stored in lake water.When the two organisms are incubated together in sapwood blocks, growth of F. pectinovorum is synergistically affected, while growth of B. subtilis is antagonised. However, no antagonism of enzyme production was evident. The levels of biological activity in the sapwood in these laboratory experiments were much higher than the values observed in the natural lake system. The concentration effect obtained in the laboratory system, in contrast to the dilution effect occurring in the lake environment, is undoubtedly responsible for this variance. Results indicate that the rate at which permeability changes occur could possibly be accelerated by replacing the natural lake system with an enclosed tank system.     

Evaluating methods for storability assessment and determination of vitality status of container grown Norway spruce transplants after frozen storage

ABSTRACT

Autumn sown small seedlings for later transplanting into large containers have been introduced in Swedish forest tree nurseries. Containerized transplants of Norway spruce (Picea abies (L.) Karst.) from three Swedish nurseries were frozen stored during the autumn of 2014 to find out storability and post-storage vitality. Seedling storability was determined by measuring electrolyte leakage after freezing shoots to ?25°C (SE L _diff?25), by measurements of dry matter content (DMC) of seedling shoots and by the commercial molecular test ColdNSure?. Vitality of seedlings after storage was determined by measuring the leakage of electrolytes from shoots (SEL), and seedlings were also tested in regrowth tests. All three methods for storability assessment gave similar predictions, except in one case where DMC showed “not storable” for successfully stored seedlings. Our results indicated that young transplants can be successfully short term stored before reaching the target levels for safe long-term storage of conventional seedlings. Early storage of young transplants resulted in low post-storage survival and vitality expressed as root growth capacity and shoot electrolyte leakage (SEL). A prolonged duration in storage generally resulted in lower survival as well as lower root growth capacity and higher levels of SEL, especially for seedlings stored at earlier dates.     

Uncertainty in detecting climate change impact on the projected yield of black spruce (Picea mariana)

The empirical growth and yield (G&Y) curves used in most timber supply models assume that growth conditions are invariable over time, which may not be correct given the projected future climate. However, errors in G&Y models can be quite large, and we therefore wanted to know the probability of detecting climate change-induced growth anomalies as a departure from current G&Y predictions. The work was carried out in a boreal forest study area in Eastern Canada, where Picea mariana Mill. BSP (black spruce) is the dominant species. Climate change effects were incorporated into G&Y predictions as correction factors obtained from process-based simulations of growth using current or projected climate. Uncertainty in G&Y projections was quantified through the inclusion of sampling and model errors in a bootstrap re-sampling scheme that yielded a percentile distribution of possible differences between G&Y curves that included or did not include climate change effects. Results yielded an average projected increase in productivity of 29% under future climate conditions for the black spruce strata in the study area. The probability of the climate change-modified G&Y predictions being significantly different from the current G&Y projections is 75% when considering the sampling error alone, and of 67% when both the sampling and modelling errors are included. Although incomplete in terms of what sources of error have been included, this study demonstrates the type of information that can be generated on the propagation of uncertainty in G&Y projections and, ultimately, on timber supply.     

Quality of timber products from Norway spruce

Summary The overall aim of this study and series of papers is to address the key variables for timber quality and to optimize the utilization of Norway spruce timber with respect to construction purposes. It is the end-user's degree of overall satisfaction that determines the quality of a product. Therefore, the performance of structural timber cannot solely be defined by mechanical properties. Geometric performance (warp) must be improved if timber is to continue as an important building material.An experimental study of the spatial variation in warp and bending properties of fast-grown Norway spruce is introduced. In this paper, the growth characteristics are presented as a function of stand and location in the tree. The knot area ratio (KAR) was considerably higher in the core (0.31) compared with timber closer to bark (0.21). The top log studs had higher KAR (0.38) than the corresponding butt log studs (0.31). The average grain angle was 3.5% ( 2°) and appeared not to vary radially. The presence of compression wood was much more common in the top log timber (75%) than in the butt log (44%). However, no consistent radial variation in compression wood was found.The authors gratefully acknowledge the support from EEC Forest programme, Contract No. MA2B-0024 and from Södra Timber AG from NUTEK project No. 9100554     

Effects of using certain tree species in forest regeneration on volume growth,timber yield,and carbon stock of boreal forests in Finland under different CMIP5 projections

We studied how the use of certain tree species in forest regeneration affected the volume growth, timber yield, and carbon stock of boreal forests in Finland under the current climate (1981–2010) and recent-generation global climate model (GCM) predictions (i.e., multi-model means and individual GCMs of CMIP5), using the representative concentration pathways RCP4.5 and RCP8.5 over the period 2010–2099. Forest ecosystem model simulations were conducted on upland national forest inventory plots throughout Finland. In a baseline management regime, forest regeneration was performed by planting the same tree species that was dominant before the final cut. In alternative management regimes, either Scots pine, Norway spruce, or silver birch were planted on medium-fertility sites. Other management actions over rotation were done as in a baseline management. Compared to baseline management, an increased planting of birch resulted in relative sense highest increase in the volume growth, timber yield, and carbon stock in forests in the south, especially under severe climate projections (e.g., multi-model mean RCP8.5, and GCMs such as HadGEM2-ES RCP8.5 and GFDL-CM3 RCP8.5). This situation was opposite for Norway spruce. In the north, the volume growth, timber yield, and carbon stock of forests increased the most under severe climate projections (e.g., multi-model mean RCP8.5 and CNRM-CM5 RCP8.5), regardless of tree species preference. The magnitude of the climate change impacts depended largely on the geographical region and the severity of the climate projection. Increasing the cultivation of birch and Scots pine, as opposed to Norway spruce, could be recommended for the south. In the north, all three species could be cultivated, regardless of the severity of climate change.     

Persistence of a biocontrol strain of Phlebiopsis gigantea in conifer stumps and its effects on within‐species genetic diversity

Fungal isolations and genetic fingerprinting were used to determine whether Phlebiopsis gigantea stump treatment against Heterobasidion annosum sl. using a single genotype (Rotstop) would affect the genetic diversity of P. gigantea populations. The survival time of P. gigantea was longer in Norway spruce (Picea abies) stumps compared to Scots pine (Pinus sylvestris) as no isolates were obtained from pine stumps 6 years after treatment, whereas in about half of the spruce stumps the fungus was still present. The usage of Rotstop did not seem to increase the occurrence of the fungus 5 years after the treatment in fresh (1‐year‐old) untreated stumps within the same forest stands. All the isolates from the 6‐year‐old treated spruce stumps were identical in genotype with the Rotstop‐strain, whereas all isolates from the fresh untreated spruce and pine stumps differed from it. Within the treated pine stand, the biocontrol usage seemed to have caused a slight reduction in genetic markers not related to Rotstop, but there were no statistically significant differences between the marker frequencies and the local natural population. Thus, Rotstop is not likely to cause any immediate threat to the genetic diversity of P. gigantea.     

Dynamics and potentials of carbon sequestration in managed stands and wood products in Finland under changing climatic conditions

Carbon (C) sequestration was studied in managed boreal forest stands and in wood products under current and changing climate in Finland. The C flows were simulated with a gap-type forest model interfaced with a wood product model. Sites in the simulations represented medium fertile southern and northern Finland sites, and stands were pure Scots pine and Norway spruce stands or mixtures of silver and pubescent birch.

Changing climate increased C sequestration clearly in northern Finland, but in southern Finland sequestration even decreased. Temperature is currently the major factor limiting tree growth in northern Finland. In southern Finland, the total average C balance over the 150 year period increased slightly in Scots pine stands and wood products, from 0.78 Mg C ha⁻¹ per year to 0.84 Mg C ha⁻¹ per year, while in birch stands and wood products the increase was larger, from 0.64 Mg C ha⁻¹ per year to 0.92 Mg C ha⁻¹ per year. In Norway spruce stands and wood products, the total average balance decreased substantially, from 0.96 Mg C ha⁻¹ per year to 0.32 Mg C ha⁻¹ per year. In northern Finland, the total average C balance of the 150 year period increased under changing climate, regardless of tree species: in Scots pine stands and wood products from 1.10 Mg C ha⁻¹ per year to 1.42 Mg C ha⁻¹ per year, in Norway spruce stands and wood products from 0.69 Mg C ha⁻¹ per year to 0.99 Mg C ha⁻¹ per year, and in birch stands and wood products from 0.43 Mg C ha⁻¹ per year to 0.60 Mg C ha⁻¹ per year.

C sequestration in unmanaged stands was larger than in managed systems, regardless of climate. However, wood products should be included in C sequestration assessments since 12–55% of the total 45–214 Mg C ha⁻¹ after 150 years' simulation was in products, depending on tree species, climate and location. The largest C flow from managed system back into the atmosphere was from litter, 36–47% of the total flow, from vegetation 22–32%, from soil organic matter 25–30%. Emissions from the production process and burning of discarded products were 1–6% of the total flow, and emissions from landfills less than 1%.     

Comparing multipurpose forest management with timber management,incorporating timber,carbon and oxygen values: A case study

Abstract

This paper comparatively examines two forest management planning approaches: multipurpose forest management and traditional timber management, with carbon, timber and oxygen production objectives in mind. The effects of both approaches on carbon and oxygen values were estimated with an oxygen and carbon flow matrix, while timber production was modelled through a growth and yield model. The estimated values were simultaneously integrated into a linear programming model developed for this study. The objective was to maximize the net present value (NPV) of the profits of timber, oxygen and carbon under the constraints of an even flow of timber production and ending forest inventory for each planning approach. The results showed that the ecological and environmental regulations in multipurpose management substantially decreased the NPV of timber production even though they increased the NPV of carbon and oxygen flow. The results also indicated that over a 100 year planning horizon the total NPV of all forest ecosystem values including carbon, timber and oxygen is almost the same (only 1.9% reduction in multipurpose management approach) in both management approaches. Although multipurpose management creates more NPV of carbon and oxygen than timber management does, the latter provides better results in terms of timber production. It is therefore important to take into account the NPV of all apparent and quantifiable forest values in preparing forest management plans, particularly in developing new management planning approaches.