Proportion Of Sapwood Research Articles

Analysis of sawn lumber production from logging residues of branchwood of Aningeria robusta and Terminalia ivorensis

One way of meeting the supply demands of the wood industry is through the reduction of waste in timber processing. It has been estimated in Ghana that for every tree felled, nearly 50% of the tree volume is left in the forest in the form of branches, crownwood, and stumps. In this study, the potential of utilizing branchwood as raw material from logging residues to help meet the timber demands of the downstream processing sector was analyzed experimentally. The sawing characteristics of the branchwood of Aningeria robusta and Terminalia ivorensis with diameters in the range 10–25 cm using live sawing and cant sawing methods were determined using a randomized complete block design, 2 × 4 factorial with three replications. Experimental results indicate that, the relative lumber value yields for first and second grade boards of A. robusta and T. ivorensis branches were 25 and 20%, respectively, while the green lumber volume yields were 40 and 32%, respectively. A high proportion of sapwood and the occurrence of washboarding in T. ivorensis contributed to that species’ relatively low lumber value and volume yield. The experimental results further indicate that the sawing technique used had no significant influence on lumber yields. However, at 5% level of significance, significant differences in lumber yield existed between some of the diameter classes.

Faible différenciation génétique, à partir d'amplification aléatoire d'ADN polymorphe (RAPD), entre les types de pin sylvestre (Pinus sylvestrisL.) d'altitude et de plaine dans les Alpes à climat continental

Random amplified polymorphic DNA (RAPD) patterns show weak genetic differentiation between low- and high-elevation types of Scots pine (Pinus sylvestris L.) in dry continental valleys in the Alps. Two types of Scots pine (Pinus sylvestris L.), found either in the lowland or in the subalpine zone, are morphologically distinguished in the central-Alpine Valais (Switzerland), a dry continental valley. The low-elevation pine forests show signs of die-back since the early 1990s. We selected four elevational population pairs in the area, and two additional pairs in two other central-Alpine regions. Genetic differentiation between the two pine types, i.e. between elevations, and between two classes of vitality were studied using random amplified polymorphic DNA (RAPD). Growth in diameter and sapwood proportion was further assessed. Population pairs, with one exception, showed weak, but significant genetic differentiation (ΦST = 4.2% - 5.8%). On the other hand, there was no correlation between genetic data and the die-back observed. We consider disruptive evolution, postglacial migration, phenological separation or wind directions as possible explanations. Differences in growth and sapwood proportions supported the assumption of adaptation to local hydrological regimes. ecotypes / RAPD / growth rings / forest die-back / genetic variation

Sapwood development in Pinus radiata trees grown for three years at ambient and elevated carbon dioxide partial pressures.

Clonal trees of Pinus radiata D. Don were grown in open-top chambers at a field site in New Zealand for 3 years at ambient (37 Pa) or elevated (65 Pa) carbon dioxide (CO2) partial pressure. Nitrogen (N) was supplied to half of the trees in each CO2 treatment, at 15 g N m-2 in the first year and 60 g N m-2 in the subsequent 2 years (high-N treatment). Trees in the low-N treatment were not supplied with N but received the same amount of other nutrients as trees in the high-N treatment. In the first year, stem basal area increased more in trees growing at elevated CO2 partial pressure and high-N supply than in control trees, suggesting a positive interaction between these resources. However, the relative rate of growth became the same across trees in all treatments after 450 days, resulting in trees growing at elevated CO2 partial pressure and high-N supply having larger basal areas than trees in the other treatments. Sapwood N content per unit dry mass was consistently about 0.09% in all treatments, indicating that N status was not suppressed by elevated CO2 partial pressure. Thus, during the first year of growth, an elevated CO2 partial pressure enhanced carbon (C) and N storage in woody stems, but there was no further stimulus to C and N deposition after the first year. The chemical composition of sapwood was unaffected by elevated CO2 partial pressure, indicating that no additional C was sequestered through lignification. However, independent of the treatments, early wood was 13% richer in lignin than late wood. Elevated CO2 partial pressure decreased the proportion of sapwood occupied by the lumina of tracheids by up to 12%, indicating increased sapwood density in response to CO2 enrichment. This effect was probably a result of thicker tracheid walls rather than narrower lumina.

Heartwood, sapwood and bark content, and wood dry density of young and mature teak (Tectona grandis) trees grown in Costa Rica

The aim of this study was to evaluate the heartwood, sapwood and bark content, and wood dry density in young and mature teak (Tectona grandis) trees. For this, 17 plantations were selected from 11 sites representing different climatic conditions and plantation densities (156 to 1600 trees ha–1, and line planting). From these plantations, a total of 87 trees with ages between 5 and 47 years were felled for stem analysis. The highest heartwood proportion of stem volume (over bark) was 61% and the lowest 0.4%. The sapwood proportion ranged between 24 and 72%, while bark represented from 14 to 37% of the total volume. Heartwood proportion was significantly different (P < 0.05) among climatic zones: ‘wet’ sites producing less heartwood than ‘dry’ sites. Stem diameter (under bark) and heartwood diameter at different stem heights differed among sample trees, even when plotted in relative values to avoid dependency with stem size. Dry density was statistically different between 8-year-old trees or younger and 47-year-old trees, and between line planting trees and 13-year-old trees or younger, but did not differ statistically between line planting trees and mature trees. No significant differences were found between climatic zones or between different stand densities. Dry density values for T. grandis plantations in Costa Rica are similar to those reported elsewhere.

Irregular Heartwood Formation in Maritime Pine (Pinus pinaster Ait):Consequences for Biomechanical and Hydraulic Tree Functioning

As the proportion of sapwood (SW) transformed into heartwood (HW) is irregular both radially and longitudinally in trunks of Maritime pine (Pinus pinaster Ait.), it has been suggested that HW formation is a developmental process, regulated internally within the tree. In trees where stem growth is eccentric due to stem lean or wind action, the number of annual growth rings of SW transformed into HW is greater on the compressed side of the tree. To determine the contribution to bending stiffness, if any, of this prematurely formed HW, four point bending tests were carried out on fresh HW and SW samples taken from the same growth ring, or neighbouring growth rings, at different cross-sectional positions at a height of 2m from six 52-year-old Maritime pines. The mean (±s.e.) modulus of elasticity (E) was 7.6±0.3GPa (longitudinal direction) for all samples. No significant differences in E were found between HW and SW; thus HW does not play a significant mechanical role in bending stiffness. To test a second hypothesis that early HW formation on the compressed side of trees may maintain a constant, optimal volume of SW around the tree, the Pipe Model Theory was applied to 12 52-year-old leaning Maritime pines (angle of lean varied from 0–22°). The surface area (S) of the SW was determined at different heights up the trunk and correlated with crown surface area (Scrown). Regressions between SSWandScrown were highly significant, thereby supporting the theory that HW formation and extension is controlled internally in Maritime pine. HW formation in Maritime pine then serves to maintain an optimal proportion of functional SW which is an important criterion for survival in a species often subjected to severe drought for long periods.

Estimating water use by sugar maple trees: considerations when using heat-pulse methods in trees with deep functional sapwood.

Accurate estimates of sapwood properties (including radial depth of functional xylem and wood water content) are critical when using the heat pulse velocity (HPV) technique to estimate tree water use. Errors in estimating the volumetric water content (V(h)) of the sapwood, especially in tree species with a large proportion of sapwood, can cause significant errors in the calculations ofsap velocity and sap flow through tree boles. Scaling to the whole-stand level greatly inflates these errors. We determined the effects of season, tree size and radial wood depth on V(h) of wood cores removed from Acer saccharum Marsh. trees throughout 3 years in upstate New York. We also determined the effects of variation in V(h) on sap velocity and sap flow calculations based on HPV data collected from sap flow gauges inserted at four depths. In addition, we compared two modifications of Hatton's weighted average technique, the zero-step and zero-average methods, for determining sap velocity and sap flow at depths beyond those penetrated by the sap flow gauges. Parameter V(h) varied significantly with time of year (DOY), tree size (S), and radial wood depth (RD), and there were significant DOY x S and DOY x RD interactions. Use of a mean whole-tree V(h) value resulted in differences ranging from -6 to +47% for both sap velocity and sap flow for individual sapwood annuli compared with use of the V(h) value determined at the specific depth where a probe was placed. Whole-tree sap flow was 7% higher when calculated on the basis of the individual V(h) value compared with the mean whole-tree V(h) value. Calculated total sap flow for a tree with a DBH of 48.8 cm was 13 and 19% less using the zero-step and the zero-average velocity techniques, respectively, than the value obtained with Hatton's weighted average technique. Smaller differences among the three methods were observed for a tree with a DBH of 24.4 cm. We conclude that, for Acer saccharum: (1) mean V(h) changes significantly during the year and can range from nearly 50% during winter and early spring, to 20% during the growing season;(2) large trees have a significantly greater V(h) than small trees; (3) overall, V(h) decreases and then increases significantly with radial wood depth, suggesting that radial water movement and storage are highly dynamic; and (4) V(h) estimates can vary greatly and influence subsequent water use calculations depending on whether an average or an individual V(h) value for a wood core is used. For large diameter trees in which sapwood comprises a large fraction of total stem cross-sectional area (where sap flow gauges cannot be inserted across the entire cross-sectional area), the zero-average modification of Hatton's weighted average method reduces the potential for large errors in whole-tree and landscape water balance estimates based on the HPV method.

Rate and Depth of Sapwood Occlusion Following Inoculation of Pines with Bluestain Fungi

Abstract Length of sapwood lesions, depth of sapwood occlusion, and proportion of sapwood occluded increased generally but irregularly through the first 9 weeks following inoculation of small (17-32 cm dbh) Pinus ponderosa with Ophiostoma minus or Leptographium terebrantis. No significant increases were detected between 9 and 64 weeks. The average proportion of sapwood depth occluded at 4 weeks ranged from 0.1-0.15 for O. minus and 0.2-0.4 for L. terebrantis. This rate of occlusion was judged inadequate per se to account for development of crown symptoms in trees following mass attack by bark beetles. For. Sci. 38(1):34-44.

Influence of stand density on log quality of lodgepole pine

We examined the relationship between stand density and stem quality characteristics for lodgepole pine (Pinuscontorta). The influence of initial stand density on end of rotation log quality was inferred by analyzing data from unmanaged, rotation-age stands. Quality characteristics examined included first log branch diameters, taper, wood density, and the proportion of sapwood. After differences in diameter at breast height were accounted for, only branch size was strongly influenced by stand density. A strong negative exponential relationship was found between the mean of the five largest branches per first log and number of trees per hectare.

Utilisation potential of plantation-grownEucalyptus nitens

Summary 20-year-old plantation-grown Eucalyptus nitens Maiden (shining gum) trees were examined for the production of structural and appearance products from sawn timber. Log characteristics were examined and measurements made of peripheral longitudinal strain. Basic density and mechanical strength characteristics of sawn timber were determined. Four commercial drying schedules were applied to 25 mm and 50 mm thick back—and quarter-sawn products. Measurements for twist spring, bow, width and thickness were made on the 50 mm boards before and after seasoning, and all boards were machined and graded to Australian Standard (AS) 2082 “Visually stress-graded hardwood for structural purposes”. The logs contained a high proportion of sapwood, and the basic density of the wood was lower than that reported for heartwood of mature E. nitens, though the moduli of rupture and elasticity, and crushing strength were comparable. The method of sawing only influenced the amount of bow in freshly sawn products. Drying redu...

Fence posts from young trees irrigated with sewage effluent

Summary Round posts and wood samples from fast-grown planted trees, irrigated with sewage effluent, only five years of age, at Mildura, Victoria, were tested for basic density, strength properties and preservative absorption. The full range of tests were made with Eucalyptus grandis (flooded gum) and E. botryoides (southern mahogany), whereas only density measurements could be carried out on Casuarina cunninghamiana (river she-oak) because of severe splitting of the post sections on drying. It is unlikely that marketable round posts can be produced from trees of this species grown under such conditions. The proportion of sapwood in trees of all three species was found to be high, and density values were considerably lower than those for the heartwood of butt logs from mature trees of the same species. However, measurements of maximum load and modulus of rupture showed that strength properties were sufficiently high for posts of these two eucalypt species to meet any strength requirements for fencing. The sapwood of both eucalypts was found to be easily and uniformly penetrated under pressure with either CCA or creosote preservatives. Sap replacement treatment, on the other hand, although producing adequate retentions, gave variable penetration patterns.

Fungal deterioration of second-growth Douglas-fir logs in coastal British Columbia

Fungal deterioration of second-growth Douglas-fir logs, felled each month from August 1961 to May 1962, was studied 2, 4, and 6 years after felling. Decay increased from 10% of log volumes after 2 years to 47% after 6 years. The rate of decay, particularly for the brown cubical type, was greater for autumn- and winter-felled logs than for those felled in the spring and late summer, and closely paralleled the seasonal pattern of ambrosia beetle attack.Decay rates increased with decreasing log size, increasing percentage of sapwood, and increasing height of log above ground. For the same diameter of log, base logs decayed less rapidly than second logs, possibly because of their lower proportion of sapwood in relation to heartwood.Decay expressed as a percentage of total log volume (Y) may be estimated (R2 = 0.71) with the following equation: Y = 13.2 + 10.7X1 − 3.2X2, where X1 = years elapsed and X2 = d.i.b. (diameter inside bark) top of log.Of 30 wood-decay fungi isolated, Naematoloma sp. (N. capnoides or N. fasciculare), which causes a white rot, was associated with the most decay. Fomes pinicola was mainly responsible for brown cubical sap rot, while Poria monticola and P. carbonica caused a brown cubical heart rot at the ends of logs.The significance of variations in deterioration rate and fungal associates is discussed in relation to log durability and salvability.

SOME FACTORS INFLUENCING THE SUSCEPTIBILITY OF TIMBER TO BOSTRYCHID ATTACK

SUMMARY In this paper common factors influencing the susceptibility of potentially susceptible timbers to bostrychid attack are outlined. In field work conducted at Grafton, spotted gum trees (Eucalyptus maculata Hook) were selected for exposure to bostrychid attack. It was evident that the initial attack on the billets was concentrated during the first month that they were exposed. No attack occurred on billets during June, July and August. The chief bostrychid species found at Grafton were Xylion cylindricus Macl., Xylion collaris Er., Xylobosca bispinosa Macl., and Xylodeleis obsipa Germar., Xylosocus gibbicollis Macl. and Bostrychopsis jesuita F. occurred in small numbers. X. cylindricus appeared consistently in large numbers and seemed to be the most common bostrychid although at times large numbers of X. bispinosa were found. From the laboratory and field work it was found that the following factors were important in relation to bostrychid attack: — i. nature of the surface of the timberii. positioning of the timberiii. relative proportion of sapwood and heartwoodiv. moisture content of the sapwoodv. climatic conditions. Although the incidence of bostrychid attack depends on the combination of these factors (and probably others), the most important and complex criterion appears to be (iv) moisture content of the timber. The moisture content range of timber in which successful bostrychid attack can occur and the exact regions of the sapwood where the moisture content is important for the developmental stages in the bostrychid life cycle, have not yet been determined.

Sap-Stains of Wood

SCHEFFER and Lindgren1 present a summary of approximately ten years of field and laboratory work on sap-stains of wood. They state that market demands for wood products are becoming more exacting, making stained wood more difficult to dispose of. Losses from degradation are in general decreasing because of improved methods in controlling stain. Chemical, mechanical, and fungus stains are described and discussed as to symptoms, cause, timber species involved, effect on various wood properties, and control, the major emphasis being on blue stains caused by fungi. In the United States blue sap stains are of greater importance in the south than in any other region, although locally and seasonally important also on the west coast and in northern Idaho and contiguous regions. The chief factors influencing the development of fungus blue stains in sapwood lumber and other wood products are temperature, oxygen, and water. No correlation Was found between wood density and susceptibility to stain. Flat-grained lumber was slightly more susceptible to stain than edge-grained, due to the greater number of rays exposed and the larger proportion of sapwood. Wood once seasoned and remoistened was less susceptible than unseasoned wood, but not significantly so. No difference was found in susceptibility to stain between winter-cut and summer-cut timber.