A comparison of needle retention on Japanese black pine and Japanese red pine

Needle retention (number of needle sets), needle density, height increment and radial increment were surveyed on seven Japanese black pines (Pinus thunbergii Parl.) and seven Japanese red pines (Pinus densiflora Sieb. et Zucc.) growing on the same site. Number of needle sets on branches with respect to whorl position was estimated visually. In 1999, maximum summer needle retention was observed on the fifth and sixth whorl from the top, with values of 3.4 needle sets for the black pines and 2.4 needle sets for the red pines, respectively. The needle trace method (NTM) was used to determine needle retention and needle density along the main stems retrospectively for the years 1968–1998. The long-term mean summer needle retention along the main stem was 3.7 needle sets for the black pines and 2.2 needle sets for the red pines. In both pine species, the number of needle sets varied from year to year. However, the long-term budget between newly born and annually shed needle sets was in equilibrium. The long-term average of needle density per cm of stem shoot was 9.4 needle pairs for the black pines and 7.4 needle pairs for the red pines. The results showed clear intra-specific and inter-specific similarities in needle retention, height increment and radial increment trends. The values for number of needle sets, height increment and radial increment positively increased with favorable growing conditions, whereas the value of needle density had an opposite tendency.     

Thinning method and intensity influence long-term mortality trends in a red pine forest

Tree mortality shapes forest development, but rising mortality can represent lost production or an adverse response to changing environmental conditions. Thinning represents a strategy for reducing mortality rates, but different thinning techniques and intensities could have varying impacts depending on how they alter stand structure. We analyzed trends in stand structure, relative density, stand-scale mortality, climate, and correlations between mortality and climate over 46 years of thinning treatments in a red pine forest in Northern Minnesota, USA to examine how thinning techniques that remove trees of different crown classes interact with growing stock manipulation to impact patterns of tree mortality. Relative density in unharvested plots increased during the first 25 years of the study to around 80%, then began to plateau, but was lower (12–62%) in thinned stands. Mortality in unharvested plots claimed 2.5 times more stems yr⁻¹ and 8.6 times as large a proportion of annual biomass increment during the last 21 years of the study compared to the first 25 years, but showed few temporal trends in thinned stands. Mortality in thinning treatments was generally lower than in controls, particularly during the last 21 years of the study when mortality averaged about 0.1% of stems yr⁻¹ and 4% of biomass increment across thinning treatments, but 0.8% of stems yr⁻¹ and 49% of biomass increment in unharvested plots. Treatments that combined thinning from above with low growing stock levels represented an exception, where mortality exceeded biomass production after initial thinning. Mortality averaged less than 0.1% of stems yr⁻¹ and less than 1% of annual biomass production in stands thinned from below. These trends suggest thinning from below minimizes mortality across a wide range of growing stock levels while thinning from above to low growing stock levels can result in dramatic short-term increases in mortality. Moderate to high growing stock levels (21–34 m² ha⁻¹) may offer greater flexibility for limiting mortality across a range of thinning methods. Mean and maximum annual and growing season temperatures rose by 0.6–1.8 °C during the study, and temperature variables were positively correlated with mortality in unharvested plots. Mortality increases in unharvested plots, however, were consistent with self-thinning principles and probably not driven by rising temperatures. These results suggest interactions between thinning method and intensity influence mortality reductions associated with thinning, and demonstrate the need for broader consideration of developmental processes as potential explanations for increased tree mortality rates in recent decades.     

Flexural strength and stiffness of southern pine plywood

Summary New information is presented that concerns flexural strength and stiffness of southern pine plywood and verification of a method developed by the U. S. Forest Products Laboratory for predicting properties of plywood. This method can predict, with sufficient accuracy, properties of southern pine plywood despite the large natural variability of veneer of this species and other variables. Strength and stiffness between 3-ply and 5-ply plywood with face grain parallel to span are compared. In addition, strength and stiffness between plywood and unidirectionally laminated veneer with same number of plies and total thickness are compared.This research was supported jointly by Federal funds under the McIntire-Stennis Cooperative Forestry Reserach Act (P.L. 87-788), Alabama Project No. 910 and Alabama State appropriated research funds.     

Characterization of strength properties of branchwood and stemwood of some tropical hardwood species

The mechanical strength properties of the branchwood of Aningeria robusta and Terminalia ivorensis with diameters ranging from 10 to 25 cm were examined to determine the suitability of branchwood as raw material for downstream processing. The study precisely assessed the static bending strengths, compression strengths and shear strengths parallel to the grain of the branchwood and stemwood of T. ivorensis and A. robusta. It was observed that under static bending, the overall (sapwood and heartwood combined) modulus of rupture and modulus of elasticity of the branchwood of A. robusta and T. ivorensis were lower than that of their corresponding stemwood. The results further show that the overall compression and shear strengths parallel to the grain of the branchwood of A. robusta and T. ivorensis were higher than that of their corresponding stemwood. Under static bending, compression parallel to the grain, and shear parallel to the grain, the experimental results indicate that the sapwood of the branchwood from both T. ivorensis and A. robusta had lower strength values than that of their corresponding heartwood. Similar results were recorded for the stemwood of T. ivorensis where the heartwood had higher strength values than the sapwood. However, in the case of the stemwood of A. robusta, the sapwood had higher strength values than the corresponding heartwood.     

红松坚果生产中存在的问题及解决措施

１ 红松坚果生产中存在的主要问题１．１ 忽视红松坚果型优树的选择 优树是指在立地类型相同的条件下，选出在生长、结实和抗性上都具有明显优势的单株。目前黑龙江省绥棱、绥阳、林口、大海林、海林等地现已嫁接的１０万株（１２．３ｈｍ２）红松接穗，都是从没有经过鉴定是否为红松优树的个体上采集的，用这样的接穗建立的红松坚果园根难保证质量，因而也不能达到建园的目的。１．２ 不重视砧木优树选择和砧木的培育 砧木的营养生长和遗传特性直接影响嫁接的亲和力、结实早晚、结实数量和种子的品质。目前各地应用的野生砧木和培育砧木均…     

Variation of virulence of white pine blister rust

According to the literature the following evidence suggests racial variation in white pine blister rust: changes over site in general level of resistance; interaction of needle spot color types with crosses of western white pine; neutralization of specific resistance reactions; bark reactions and normal cankers on the same tree.     

日本黑松和赤松精英树半同胞家系生长及遗传参数分析

通过对泰山竹林寺景区引种27年生的日本黑松和赤松精英树半同胞家系生长特性和遗传参数的研究发现：（1）黑松生长量略优于赤松,它们的平均胸径分别为21．83cm和20．84cm,平均材积分别为0．264m^3和0．262m^3。从遗传特性上来看,黑松和赤松的胸径的家系h^2分别为0．7668和0．4404。（2）从家系间比较可知：黑松大岛6^#、黑松柳井3^#、当地黑松、黑松柳井2^#生长指标居于前4位,材积分别为0．4725m^3、0．3526m^3、0．3179m^3和0．3144m^3。赤松都浓3^#、赤松都浓2^#、赤松大岛1^#居于前列,材积分别为0．429m^3、0．343m^3和0．365m^3。     

Wood chemical composition as related to properties of handsheets made from loblolly pine refiner groundwood

Summary Burst and tear strengths of handsheets made from 48 pulps disk-refined from chips of varying chemical composition decreased with increasing extractive content after the independent effects of fiber morphology were specified. This result was attributed to lessened bond strength caused by reduced surface tension forces and blocking of reactive sites on the fiber surfaces.

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Zusammenfassung Berstzahl und Reißfestigkeit der Blätter von 48 verschiedenen Zellstoffen aus scheibengemahlenen Spänen mit unterschiedlichen chemischen Bestandteilen verringerten sich mit ansteigendem Extraktstoffgehalt; die davon unabhängigen Einflüsse des Faseraufbaues sind dabei berücksichtigt. Diese Tatsache wird der verminderten Bindungskraft zugeschrieben, verursacht durch die herabgesetzte Oberflächenspannung und die Blockierung von Bindungsstellen an den Faseroberflächen.

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The author appreciatively acknowledges the assistance of the Roy O. Martin Lumber Co., Alexandria, La.; R. A. Leask and J. Adams of Bauer Bros. Co., Springfield, Ohio; and D. Bower, mathematical statistician at the Southern Forest Experiment Station, New Orleans, La.     

Shear strength and perpendicular-to-grain tensile strength of defect-free Scots pine wood from mature stands in Finland and Sweden

Variations in parallel-to-grain static shear strength and perpendicular-to-grain tensile strength of Scots pine wood from mature stands in Finland and Sweden were studied by means of linear mixed model analyses. Approximately 35% of the total variation in shear strength could be described with readily available independent background variables; if the basic density was included, approximately two-thirds of the total variation could be controlled. In tensile strength perpendicular to grain, only approximately one-fourth of the total variation could be described with the respective background variables; the property was found to be independent on wood density, and the reasons for the absence of strength–density relationship are discussed.     

Fibrillar angle variation in red pine determined by Senarmont compensation

Summary Fibrillar angles were determined in the secondary wall layers of three rings across the stem of a mature red pine. The Senarmont compensation method was adopted for this study since it gives results for all three wall layers. It involves the determination of birefringence in a series of sections cut at various angles to the long axis of the tracheids. Maxima and minima in the resultant plots of birefringence versus section angle correspond to fibrillar orientations. In the early latewood of each ring, the S₂ layr was found to contain a single Z helix of small fibrillar angle and the S₁ dual S and Z helices of much flatter orientation. Results for S₃ were found to be so close to those for the corresponding S₂ layers that there was some doubt as to their validity. In each layer a slight decrease in fibrillar angle was observed between rings 4 (juvenile wood) and 12 (transition zone); a sharper decrease was seen between ring 12 and the mature ring 20. This trend corresponds inversely to tracheid length differences for the three rings. Correlations of tracheid wall thickness and overall cross-sectional dimensions with the fibrillar angle variations were less readily apparent.Contribution No. 59 from Empire State Paper Research Institute, State University College of Forestry, Syracuse, New York 13210. The authors gratefully acknowledge the discussions and advice of Drs. W. A. Côté, Jr. and R. E. Mark.     

Survival of Heterobasidion irregulare on red pine discs in cold temperatures

Disease foci of the conifer root and butt decay pathogen Heterobasidion irregulare are typically initiated following germination of spores deposited on freshly cut stumps, followed by expansion by tree to tree spread through root contacts and grafts. Although most abundant in autumn, inoculum of H. irregulare is also available during some cold winter periods in northern portions of the eastern United States. In both laboratory and field experiments, fresh stem discs of red pine (Pinus resinosa) were inoculated with H. irregulare conidia to test the null hypothesis that the pathogen would not survive prolonged exposure to cold temperatures experienced during winters in those regions. After exposure to cold for various periods of time, discs were incubated and then observed for presence of the Spiniger state of the pathogen. In each of two laboratory trials, the fungus survived on red pine discs incubated at ≤?20°C for 90 days. The field experiment was conducted during each of two winters at two infested red pine plantations. Inoculated discs were deployed periodically beginning in early winter and retrieved after various periods of time until spring. The Spiniger state of the pathogen was frequently observed on discs after laboratory incubation, even after field exposure of up to 6 months, during which temperatures ≤?25°C were sometimes recorded. Whether viable due to growth from inoculum initially placed on the discs, or natural inoculum deposited on discs exposed in the infested plantations, winter temperatures did not eliminate survival of the pathogen on this natural substrate. The potential for survival on stump surfaces during sub‐freezing temperatures during which application of stump protectants in water is impractical should be considered in evaluating the potential risk from H. irregulare to economically and environmentally valuable conifer forests of northcentral and northeastern North America.     

Belowground carbon allocation in unfertilized and fertilized red pine plantations in northern Wisconsin

We estimated carbon allocation to belowground processes in unfertilized and fertilized red pine (Pinus resinosa Ait.) plantations in northern Wisconsin to determine how soil fertility affects belowground allocation patterns. We used soil CO(2) efflux and litterfall measurements to estimate total belowground carbon allocation (root production and root respiration) by the carbon balance method, established root-free trenched plots to examine treatment effects on microbial respiration, estimated fine root production by sequential coring, and developed allometric equations to estimate coarse root production. Fine root production ranged from 150 to 284 g m(-2) year(-1) and was significantly lower for fertilized plots than for unfertilized plots. Coarse root production ranged from 60 to 90 g m(-2) year(-1) and was significantly lower for fertilized plots than for unfertilized plots. Annual soil CO(2) fluxes ranged from 331 to 541 g C m(-2) year(-1) and were significantly lower for fertilized plots than for unfertilized plots. Annual foliage litterfall ranged from 110 to 187 g C m(-2) year(-1) and was significantly greater for fertilized plots than for unfertilized plots. Total belowground carbon allocation ranged from 188 to 395 g C m(-2) year(-1) and was significantly lower for fertilized than for unfertilized plots. Annual soil CO(2) flux was lower for trenched plots than for untrenched plots but did not differ between fertilized and unfertilized trenched plots. Collectively, these independent estimates suggest that fertilization decreased the relative allocation of carbon belowground.     

Effect of post treatment temperature and humidity conditions on fixation performance of CCA-C treated red pine and southern pine

introductionWaterbornepreservativesareamajorcomponentofthewood-treatingindustrybecauseoftheireaseofapplication,lowcost,andthecleanappearanceofthewoodattertreatment.Theuseofchromatedcopperarsenate(CCA)preservativesintheUSAhasgrownfroma14%shareofthewoodpreservativesmarketin1977to73%in1987(Micklewright1993).ThisismainlyduetotheincreasinguseofCCAtreatedwoodasdecksandoutdoorstructures.ThewaterbornepreservativeCCAhasbecomeoneofthemosteffectivetreatmentsforNorthAmericanwoodproduCts,usedinapplic…     

Impact of fixation/drying conditions on fixation rate, leachability and bioefficacy in CCA-C treated red pine and southern pine

Red pine (Pinus resinosia Ait) and southern pine (Pinus spp.) sapwood blocks were pressure treated with CCA-C at retention of 6.4, 2.0, 1.5 kg?m-3 followed by fixation using 11 post-treatment schedules ranging from 50-70 °C and 5 different relative humidity conditions. The effect of these post-treatment schedules on fixation rate, chemical leachability and decay resistant once were evaluated to better understand the effects of fixation/drying conditions on leachability and biodeterioration. Southern pine blocks fixes slightly slower than red pine. Fixation of CCA at high temperature high humidity, essential initially fixation at high humidity for fixation/drying schedules, resulted in lower leaching of chromium and arsenic elements than high temperature low humidity or initially fixation at the high temperature low humidity conditions. Copper leaching was indicated no significant difference under 11 fixation/drying conditions for both species. Weight losses for southern pine by Chaetomium globosum was lower than red pine by Gloeophyllom trabeum. There were some different capacities of decay resistance for both species under those post treatment conditions.     

Impact of fixation/drying conditions on fixation rate, teachability and bioefficacy in CCA-C treated red pine and southern pine

Red pine (Pinus resinosia Ait) and southern pine (Pinus spp.) sapwood blocks were pressure treated with CCA-C at retention of 6.4, 2.0, 1.5 kgm^-3 followed by fixation using 11 post-treatment schedules ranging from 50–70 °C and 5 different relative humidity conditions. The effect of these post-treatment schedules on fixation rate, chemical leachability and decay resistant once were evaluated to better understand the effects of fixation/drying conditions on leachability and biodeterioration. Southern pine blocks fixes slightly slower than red pine. Fixation of CCA at high temperature high humidity, essential initially fixation at high humidity for fixation/drying schedules, resulted in lower leaching of chromium and arsenic elements than high temperature low humidity or initially fixation at the high temperature low humidity conditions. Copper leaching was indicated no significant difference under 11 fixation/drying conditions for both species. Weight losses for southern pine byChaetomium globosum was lower than red pine byGloeophyllom trabeum. There were some different capacities of decay resistance for both species under those post treatment conditions.     

Determination of the effective water conductivity of red pine sapwood

Summary The instantaneous profile method was used to establish the boundary desorption curve of the effective water conductivity function of red pine (Pinus resinosa Ait.) sapwood in the radial and tangential directions from nearly saturated to dry conditions at 18, 56 and 85 °C. The results obtained demonstrate that the effective water conductivity is a function of moisture content, temperature, and direction of flow. The effective water conductivity increases by several orders of magnitude (10⁴–10⁵) as moisture content increases from dry to nearly saturated conditions at a given temperature. The effective water conductivity also increases by a factor varying between 10 and 50 as temperature rises from 18 to 85 °C in the moisture content range considered. The variation of the moisture content–water potential relationship with temperature can explain part of the temperature effect. The effective water conductivity was generally higher in the radial direction than in the tangential direction in a ratio varying from about 1/1 to 3/1 depending on moisture content and temperature. Finally, the flux–gradient relationships obtained at given moisture contents were found to be linear, confirming the validity of using a moisture flux equation considering the water potential gradient as the driving force for the experimental conditions considered in the present work. The knowledge of the effective water conductivity function and of the moisture content–water potential relationship allows the utilization of a two-dimensional model of moisture movement in wood during drying using the gradient in water potential as the driving force for drying at temperatures up to 85 °C. Received 27 February 1998     

Variation in treatability of Scots pine sapwood: a survey of 25 different northern European locations

The treatability of Scots pine sapwood sampled from 25 locations in northern Europe, which was impregnated with an experimental furfuryl alcohol mix, was studied. A large variation in treatability was found between stands. The treatability was affected by anatomical properties of the trees and therefore also by the immediate climate, the sociological position of the tree in the stand, growth increments and on-stand competition. With the models applied, most parts of the differences in treatability between stands could be explained, while the treatability variation between trees within a stand remained mostly unexplained. Wider annual rings and higher latewood contents were found to increase the treatability. Models that included data on growth conditions and climate explain more of the variation in treatability, indicating that also other anatomical properties are influencing the treatability. Tree attributes and growth conditions that reduce annual ring width and latewood content decreased the treatability. Trees growing under warmer conditions and developing larger growth increments were easier to impregnate. Wood from trees growing near the timberline and under environmental conditions impairing wood growth was more difficult to treat.     

Relationships between seasonal appearance and longevity of fruitbodies of Agaricales and meteorological factors in a Japanese red pine forest

We investigated the seasonal appearance and longevity of fruitbodies of Agaricales in a mixed forest dominated by Pinus densiflora (Sieb et. Zucc.) for about 3 years. A total of 3563 fruitbodies in 27 genera from 13 families appeared; Collybia, Marasmius, Mycena, Rhodophyllus, and Lactarius were dominant. The seasonal trend of appearance of fruitbodies differed among genera. There were no significant relationships between any factors of temperature and the number of fruitbodies in any of the dominant genera or Amanita. The number of fruitbodies of Mycena and Lactarius increased with the indices of precipitation. The longevity of fruitbodies ranged from 2.6 days in Mycena to 71.9 days in Lactarius. The longevity in Collybia and Mycena, which appeared in early summer, increased as the highest daily temperature became higher. On the other hand, that of Marasmius, Amanita, Rhodophyllus, and Lactarius, which appeared in autumn, increased as the lowest daily temperature became lower. The longevity of fruitbodies in every genus surveyed except Amanita decreased as the frequency of precipitation increased. It is possible that the rate of deterioration is higher in June–July than in September–December, and the longevity of fruitbodies might vary with the temperature. On the other hand, precipitation would facilitate the appearance of fruitbodies and shorten their longevity in Mycena and Lactarius.     

Factors affecting mode I fracture energy of plantation-grown red pine

Summary Mode I fracture energy of premature plantation-grown red pine is discussed, for crack growth in the longitudinal direction. It is demonstrated that fracture energy is influenced by moisture content at test and the direction that stress is applied in the radial-tangential plane. Secondary influences of moisture conditioning and density on fracture energy were observed, with the severity related to the moisture content of the material at test. Discrepancies with findings in the literature are identified and discussed. It is likely that results of this study apply to other conifer species with low extractive contents.The work was undertaken with financial support from the Natural Sciences and Engineering Research Council of Canada under operating grants OGP 0004417 and OGP 0109473     

Variation and heritability of resistance of lodgepole pine to Western gall rust

Families of pine seedlings from 40 open-pollinated trees (mother trees) from the interior of British Columbia (B. C.) were inoculated with two spore mixtures, one from the coast and the other from the interior of B. C. The relative susceptibilities of the 40 families to each spore mixture was assessed and narrow sense heritability with respect to disease resistance was estimated. The results are presented and discussed.