Butt Logs Research Articles

Increment and decay in Norway spruce and Scots pine after artificial logging damage

The effects of depth, size, location, and season of artificial logging damage on increment and decay of Norway spruce ( Picea abies (L.) Karst.) and Scots pine ( Pinus sylvestris L.) trees were studied in long-term experiments in central Finland. Damage types applied were root damage, root collar damage, increment borer hole, and stem damage. In root collar and stem damages, two sizes (100 or 400 cm2) and depths (shallow or deep) were applied. Five to 20 years after damaging, the damages did not result in a decrease in radial, height, or volume increment. In Norway spruce, the frequency of decay in the root collar and stem damages was high. From large and deep damages, decay spread faster than from smaller and shallow ones. In Scots pine, a lower proportion of trees were decayed compared with Norway spruce. Increment coring resulted in decay in most of the trees, but the decay spread slowly. The effect of compass direction or the month of damaging was negligible. The most common decay fungus in Norway spruce was Stereum sanguinolentum (Alb. & Schwein. Fr.:) Fr. In Scots pine, only nondecay fungi were isolated. In general, logging damages decreased sawlog production through the rejection of butt logs containing decay or discoloration.

Impact of log position in the tree on mechanical and physical properties of black spruce medium-density fibreboard panels

Mechanical and physical properties of medium-density fibreboard (MDF) panels made from black spruce ( Picea mariana (Mill.) BSP) top, middle, and butt logs were studied. The analysis of variance and analysis of covariance were both performed to examine the impact of log position in the tree on panel modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), linear expansion (LE), thickness swell (TS), and water absorption. Results indicate that MOE and IB strength of MDF panels made from top and middle logs were significantly superior to those of panels made from butt logs; however, there was no significant difference in MOE and IB between panels made from top and middle logs. Water absorptions of top and middle log panels were significantly lower than that of panels made from butt logs, and the difference in water absorption between panels made from top and middle logs was not significant. TS of top log panels was the smallest among the panels from the three log positions in the tree and was significantly different from those of middle and butt log panels. TS of butt log panels was the highest, which was significantly different from that of top and middle log panels. The differences in LE among the panels made from top, middle, and butt logs were not significant. The comparison of MOR of top, middle, and butt log panels was dependent on panel density because of the interactions among the three groups. Top and middle log panels showed superior properties, because the thinner cell walls of fibres from top and middle logs resulted in an increased compaction ratio compared with the butt log panels. Panel density affected both panel MOR and MOE considerably; however, its impact on IB, LE, TS, and water absorption was not significant in this study. The equations describing the linear relationships between MOR, MOE, and panel density were developed.

The effect of initial planting density on branching characteristics of Eucalyptus pilularis and E. grandis

Summary Branch-related defects can significantly decrease the quality of plantation eucalypt logs grown for solid-wood products. In this study we examined the effect of initial spacing on branching characteristics of 5-y-old plantation-grown Eucalyptus grandis and E. pilularis on the North Coast of New South Wales. For each sample tree all branches on the lower stem (the butt log, 0.3–6 m) were assessed for diameter, angle and condition. Trees were sampled in plots grown at four initial planting densities: 838 (3 m x 4 m), 1111 (3 m x 3 m), 1667 (3 x 2 m) and 3333 (3 m x 1 m) trees ha-1. The butt log of both species contained 55–70 branches, regardless of the initial density. Initial density did not affect branch formation, but it did affect the subsequent growth and persistence of branches. Lower initial density increased both the mean branch diameter and the number of large branches (> 2.5 cm diameter) per tree in both species. Branch size also increased with height up the stem, but the rate of increase was not different between densities. A major difference between species was that E. pilularis had more small dead branches that had not been shed. A single spacing prescription is possible for both species because there was no difference between species in the relationship between large branches and density.

Effects of height on physical properties of wood of jhau (Camarina equisetifolia)

Summary Moisture content, and tangential, radial and longitudinal shrinkage, and basic density were assessed in samples of wood from near the centre of the cross-section at three different heights in 25-y-old jhau (Casuarina equisetifolia). The mean initial moisture content was 41% in the butt log, 40% in the centre log and 48% in the crown log. Mean tangential shrinkage was 10% in the butt, 9% in the centre and 11% in the crown. The corresponding measurements for radial shrinkage were 6%, 5% and 5%, and for longitudinal shrinkage 0.4%, 0.3% and 0.5%. There were no statistically significant differences in either moisture content or radial and longitudinal shrinkage with increasing height above ground, but differences in tangential shrinkage were significant at P< 0.05. The overall mean basic density was about 800 kg m−3, and this property varied a little with height in the tree.

Wood decay associated with logging wounds inParashorea malaanonan

Wood decay associated with wounding in 40 trees of Parashorea malaanonan growing in Ulu Segama Forest Reserve, Sabah, Malaysia, was estimated 7 years after logging in compartments where reduced-impact (RIL) or conventional (CL) logging methods were used. Trees of ≥30 cm diameter were felled and dissected to determine the volume of log occupied by decay. Scrapes were the most common types of wounds sampled, followed by basal wounds, broken tops or branches and butt log wounds. All wounded trees examined had decay, whereas only 25% of trees ×30 cm diameter at breast height of this species in the reserve typically had stem decay. Median defect to gross volume of tree was ∼5%, and was similar for trees in RIL and CL areas. However, defect volume per wound was greater in trees from CL areas relative to RIL areas, in particular, mid-bole wounds had greater defect volume in trees in CL areas as opposed to trees in RIL areas. The mean rate of decay was estimated at 68 cm3 of timber per year for each cm2 of wound area. Defect volume was positively correlated with wound size but was unrelated to tree size. P. malaanonan is vulnerable to wood decay following wounding; therefore, in eastern Sabah forests, where this species comprises a large proportion of the commercial volume, efforts to reduce incidental damage to residual stems during harvesting operations are an important component in protecting the growing stock.

Comparison between HT-dried and LT-dried spruce timber in terms of shape and dimensional stability

Abstract The performance of timber studs from Norway spruce (Picea abies) in terms of shape and dimensional stability was evaluated. The shape stability studied included three modes of distortion, i.e. twist, bow and spring. The dimensional stability was assessed by measuring longitudinal shrinkage and swelling properties. The study comprised 96 studs measuring 45 mm×70 mm×2500 mm from 15 butt logs. Half the studs from each log were dried using a high-temperature method (HT) at 115°C, while the other half were dried using a conventional low-temperature method (LT) at 70°C. Distortion in the studs was measured at moisture contents of 14% and 9%. The HT-dried timber had significantly lower distortion values than the LT-dried timber. As a result, 80% of the high-temperature-dried studs were able to pass the limits for distortion, while only 60% of the low-temperature-dried studs passed the same limit. Studs cut close to the pith displayed the largest twist, independent of the drying method. A simple model for predicting twist that was used in previous studies was also valid for HT-dried timber. The most important parameters in this model for both HT- and LT-dried timber were grain angle, annual ring curvature and tangential shrinkage.

Auswirkung von Kernrissen und Längskrümmung auf die Ausbeute von 32-jährigem Plantagen-Eukalyptus (Eucalyptus globulus Labill.)

Thirty dominant or co-dominant, straight trees were selected from a 32-year-old thinned plantation of Eucalyptus globulus Labill. Growth strain at tree surface at breast height was estimated using a CIRAD-foret method. Log-end splits in the butt logs were measured. The butt logs were quarter-sawn following a pre-determined sawing pattern. The most common dimensions of sawn boards were 28×105×3000and 28×77×3000 mm.The volume of the curved-edge off-cuts was estimated for each butt log. The end splits in the dried sawn boards were measured and the volume of the wood containing the splits in the boards calculated.

Effects of density and microfibril orientation on the vertical variation of low-stiffness wood in radiata pine butt logs

Abstract The roles of density and microfibril angle in causing low stiffness in radiata pine butt logs were studied in detail on a 17-year-old tree. Distributions of these variables were compared with stiffness variations in the vertical direction. Results supported the hypothesis that cell ultrastructure is responsible for the vertical variation in stiffness. The microfibril orientation in tangential wall is considered to be an important factor contributing to wood stiffness because of the smaller microfibril angles compared with radial microfibril angles, and also because of the larger decrease of the microfibril angles with the rapid increase of wood stiffness in vertical direction especially in corewood zone. The microfibrils in the S3 layer fall from over 80° to angles of 54° and 51° for radial and tangential cell walls at the top of the butt log. Further study is needed for fully understanding the characteristics of S3 layers.

Inter-tree and intra-tree variations in ring width and wood density components in balsam fir ( Abies balsamea )

This study quantified and compared intra-tree and inter-tree variations in ring width and wood density components in balsam fir (Abies balsamea) grown in Quebec, Canada. In addition, the study examined correlations between ring width and wood density components at different stem positions from the stump level to the stem top. Ring width and wood density components of individual rings were measured by X-ray densitometry. Both the intra- and inter-tree variations in balsam fir are large, but the inter-tree variation is relatively smaller than the intra-tree variation. Much of the intra-tree variation is due to the radial variation, whereas the axial variation is much smaller. Compared to ring width and its components, wood density characteristics show a considerably smaller variation at both the inter- and intra-tree level. In almost all wood characteristics studied (except for latewood width), the intra- and inter-tree variations are more or less influenced by tree age. Cambial age explains more intra-tree variation in wood density components than ring width, whereas more intra-tree variation in ring width components is due to ring width. Cambial age and ring width explain a comparable percentage of variation in ring density. Only a few of the correlations between ring width and wood density components vary significantly with stem position from the stump to the stem top at the inter-tree level. In balsam fir, a negative correlation between ring density and ring width is significant in the butt log, but the correlation decreases to an insignificant level at and above a height of 3.0 m.

Stiffness gradients in radiata pine trees

A mill study of 62 trees, in which boards were reassembled into their original logs, permitted the construction of wood quality maps. In this instance stiffness profiles were obtained from butt to upper-top logs, based on machine stress grading of all boards and then averaging values from the 62 trees. Traditionally the butt log has been perceived to be the most valuable log in a tree, because it is bigger and gives a higher recovery of lumber. However, it is shown to contain a wide cone of very low stiffness wood that is confined to the first 2.4–2.7 m above ground level. Above this point stiffness gradients become cylindrical with no noticeable decrease in stiffness up the tree stem. Stiffness in all logs increased radially from pith to cambium with the greatest change being associated with the wood nearest the pith. The low stiffness at the base of the tree suggests that an alternative log bucking strategy should be considered, namely cutting a short 2.4–2.7 m butt log for plywood/LVL or for bolter sawing and only cutting standard length logs above this point. The least stiff logs (lowest 20%) yielded lumber that had an average stiffness that was over 1 GPa less than the average for the population. A case can be made for separating these logs and processing them differently.

Low-rainfall eucalypts as a potential plantation resource in south-eastern Australia for sawn appearance products

Summary Four eucalypt species were evaluated for their potential to produce sawn appearance products when grown in the low rainfall (400–600 mm y1) region of south-eastern Australia. The species were selected on the basis of their suitability for the region and the availability of sawlogs in existing plantations. The sampled trees were about 40 y-old with a minimum diameter at breast height over bark of 30 cm. A butt log 3.1 m long was harvested from ten or eleven trees of each of the following species: Eucalyptus astringens(Maiden) Maiden (brown mallet), E. cladocalyx F.Muell. (sugar gum), E. leucoxylon F.Muell. (yellow gum) and E. occidentalis Endl. (flat-topped yate). The logs were back-sawn with a conventional sawing system to produce boards mostly of 100 mm × 40 mm (nominal) cross-section. The recovery of green boards that met high-value appearance grades was poor. The recovery of select grade or better boards ranged from only 0.9% of log volume for E. leucoxylon to 8.1 % for E. astringens. The poor recoveries were mostly attributable to the small diameter of logs and the lack of silvicultural treatment in the stands from which they were cut. The results highlight the difficulties of growing high-value sawlogs in this region, without suitable silviculture. At best, given the expected long rotations, the economics of growing high-value sawlogs are likely to be marginal, and profitability will depend on other land management benefits provided by the trees. Improved genetic stock and appropriate silviculture will be critical if green recoveries (select grade and better) of at least 30–35% are to be achieved. Green recoveries of this magnitude are likely to be required for a viable sawn timber industry to be established in this region. Use of a conservative air-drying schedule resulted in little drying degrade, surface checking being the main drying defect observed. Given the level of surface checking found, in the absence of other defects 85% of boards would still have made select grade or better. Nevertheless, careful drying practices will be required to minimise surface checking in back-sawn boards of each of these species.

Impacts of Intensive Management on Black Walnut (Juglans nigra L.) Growth and Bole Quality at Mid-Rotation

Abstract High value hardwood species, such as black walnut (Juglans nigra L.), are increasingly planted and intensively managed in the hopes of profitably producing high quality logs. Success or failure of silvicultural practices used to establish these plantations are commonly judged on the basis of early diameter growth response. However, it is generally not known whether treatments judged to be successful when the stand is young translate into mid- and late-rotation bole quality and, ultimately, log value. This study revisits a 35-yr-old experimental black walnut plantation in south-central Illinois (black walnut site index50 = 23m), to evaluate how initial planting density, interplanting with nitrogen-fixing black alder (Alnus glutinosa [L.] Gaertn.), postestablishment weed control, and time of thinning impacted the productivity and bole quality at mid-rotation. Postestablishment weed control conducted at age 6–7 yr did not impact walnut diameter at age 35, but incidence of frost cracks and grade defects in the butt log (lower 2.44 m) were 100% and 30% greater, respectively, on trees receiving the weed control treatment. Time of first thinning of the alder affected walnut quality in the upper log (second 2.44 m log). The higher planting density of walnut and alder reduced the number of defects by 31% in the upper log, but at the expense of stem diameter growth. At a walnut planting density of 7.9 × 7.9 m, interplanting black alder impacted neither walnut diameter growth nor bole quality. The early thinning treatment increased the number of defects on the upper log, but not the butt log. These results suggest that intensive management can have a complex and enduring impact on black walnut plantation growth and development, and elucidate the need for long-term assessment of silvicultural treatments where bole quality is an important component of stand value. For. Sci. 49(4):522–529.

Identifying check-prone trees of Eucalyptus globulus Labill. using collapse and shrinkage measurements

Summary Fifty-nine trees were sampled from three provenances of 10-y- old Eucalyptus globulus Labill. plantations grown at two sites in South Australia. The butt logs were backsawn and 176 boards (40 mm × 100 mm × 3600 mm) from the centre cant (two to four boards per cant) were dried. A 10-mm-thick cross-section was removed 400 mm from the end of each board (corresponding to the smaller end of the log) and inspected for the presence of internal checks. The samples were ranked using the mean values of several wood properties, including tangential collapse, total tangential shrinkage, density, growth strain, microfibril angle (MFA) and cellulose crystallite width (Wcryst). The rank positions of the check-prone trees were inspected in each ranking. Tangential collapse showed good potential for identifying the check-prone trees, while total tangential shrinkage and total cross-sectional shrinkage were slightly less sensitive. Density, growth strain, MFA, Wcryst and other shrinkage properties were not as useful. It is recommended that tree breeders should use total tangential shrinkage as an indicator to identify check-prone trees, because this property is not only reliable but can be easily measured on trimmed increment cores at low cost.

Crop Tree Release Increases Growth of Mature Red Oak Sawtimber

Abstract Crop tree thinning plots were established in five stands of mature red oak (Quercus rubra, Q. velutina, and Q. coccinea) sawtimber in 1995. Initial stand ages ranged from 74 to 94 yr old with mean crop tree diameters ranging from 10.9 to 15.4 in. Growth of crop trees was monitored for the next 6 yr. The upper age limit at which oaks respond to crop tree management (high thinning) is at least 90 yr old. Although there was no significant difference in diameter growth between released and unreleased trees for the first 2 yr after release, diameter growth of released trees was significantly greater during each of the subsequent 4 yr. Crop tree release increased diameter growth of sawtimber red oak by 53%. Annual volume growth (International 1/4) increases ranged from 95% for 11 in. trees to 25% for 20 in. trees. Growth of crop trees has not decreased, relative to control trees, 6 yr after release. Formation of new epicormic branches on the butt log was largely limited to the slowest growing trees. Crop tree management should be considered as a method of managing sawtimber oak stands where maintaining high forest cover and noncommodities attributes are important considerations.

Field Note—Changes in Species, Grade, and Structure Over 48 Years in a Managed New England Northern Hardwood Stand

Abstract Three individual-tree selection harvests over a 48 yr period in a northern hardwood stand in New Hampshire resulted in an increase in the percentage of volume in trees with grade 1 and 2 butt logs from 21% (1952) to 30% (2000) in beech and 40% (1952) to 65% (2000) in sugar maple and other hardwoods. By 2000, 90% of the volume was in tolerant species.

The effect of growth strain and other defects on the sawn timber quality of 10-year-old Eucalyptus globulus Labill

Summary Fifty-nine trees were sampled from three provenances of Eucalyptus globulus Labili, in 10-year-old plantations at two separate sites. The butt logs were selected as the study sawlogs. Growth strain was measured at three heights along the log length and three circumferential positions at each height. The logs were sawn and graded before and after seasoning to appearance grade. The impact of each grade-limiting defect on the result was examined. Particular attention was given to the effect of growth strain on the percentage of sawn boards that exceeded the permissible distortion limits of Australian standard AS2796.1 as feedstock. The logs were from young, small-diameter, unpruned trees knots and pith were the primary grade-limiting defects. Average growth strain of the sawlogs and the tree diameter at breast height in combination accounted for 42% of the total variation in the percentage of excessively distorted boards. Density had no direct causal effect on this percentage, but had an indirect effect through its significant correlation with growth strain.

Epicormic Branches Affect Lumber Grade and Value in Willow Oak

Abstract A case study was conducted in a 50-yr-old bottomland oak stand in central Alabama to investigate the relationship between epicormic branches and lumber grade and value in willow oak (Quercus phellos L.). The stand had been thinned from below 7–10 yr earlier, resulting in a wide variety of epicormic branch conditions on the residual trees. A sample of 41 willow oak trees was selected before the stand was clearcut in late 1991. All merchantable logs in each tree were graded prior to felling. Average dbh of sampled trees was 19.1 in. Each tree averaged 9.5 epicormic branches on the sawlog portion of the bole. From these 41 trees, a random sample of 57 logs (31 butt logs and 26 upper logs) was shipped to a sawmill where they were sawn into lumber and graded. Epicormic branching had a large detrimental effect on log grade of individual trees. In general, as few as five epicormic branches somewhat evenly distributed on a 16 ft log was enough to cause a reduction in log grade. More importantly, defects caused by epicormic branches had a serious effect on lumber grade, particularly in the higher grades. Over 50% of the lumber volume that would have been graded as either First and Seconds or Select in the absence of epicormic branches was downgraded to No. 1 Common or below due to defects caused by epicormic branches. Based on lumber prices prevailing at the time of the study, defects caused by epicormic branches resulted in a 13% reduction in the value of the lumber produced in the final harvest. South. J. Appl. For.25(3):136–141.

Prediction of knot diameter in Picea abies (L.) Karst

(L.) Karst. from three different site indexes in south-eastern Norway. Ten branch whorls were sampled from each tree, and diameters of all the knots were measured at the radial stem plane. Knot diameter was evaluated as mean diameter of the two thickest knots in each sample whorl. The whorl with the maximum value in each tree was on average located at 30% of tree height at G11, 40% at G17 and 60% at G23. The vertical location was related to the position of the crown base, and single tree models for predicting the position and the value were constructed. Knot diameter in the butt log, i.e. in the lower 30% of tree height, was related to annual ring width and site index, and to diameter at breast height and site index.

Damage to trees due to forestry operations and its pathological significance in temperate forests: a literature review

The damage caused to temperate forests by forestry operations is examined by a review of the scientific literature. A significant proportion of the remaining trees, especially in older stands, can be damaged during mechanized selective logging in forests, when operations are carried out in summer. Damage is most often caused during transport of timber. Most of the resulting wounds occur near the base of the tree and are up to 200 cm 2 in size. Damage to roots has negative effects on tree growth. Wounds on trees are attacked by fungi, causing stain and decay. In most tree species, the spread of wound decay is extensive and devalues several metres of the butt log. Wound closure is usually too slow to have any significant effect on the incidence of wound infections, but in several tree species it may restrict the spread of decay. The financial losses in wood value at the final harvest, due to previous logging damage, are reported to be significant. Strategies are discussed for controlling the damage and wound decay in a forest, emphasizing silvicultural options for care of a stand during selective harvesting and wound treatment with appropriate dressings.

A Comparison of Felling Techniques on Stump Height and Log Damage with Economic Interpretations

Abstract This study investigated two of the many potential sources of value loss that occur during logging operations: stump heights and butt log damage. The potential value loss was determined for manual felling and five different felling heads for logging sites located in the central north island of New Zealand. Manual felling produced the highest stumps and three different felling heads (Hultdin, Timbco, and Warratah) produced second highest stumps. The group with the lowest stumps was felled with AFM Magnum and Koehring felling heads. The Warratah felling head had the lowest incidence of butt log damage, while manual felling had the highest proportion of damaged butt logs. The majority of the damage to the butt logs was slabbing damage; all felling techniques produced little stump pull damage. A comparison of the potential value loss showed that the Koehring produced the lowest potential value loss at US$128/ac, while manual felling had the highest potential value loss at over US$420/ac. West. J. Appl. For. 15(2):59-61.