Pinus Patula Trees Research Articles

Lignocellulosic characterisation of Pinus patula wood from Oaxaca, Mexico

Wood is mainly composed of carbohydrates, lignin, and smaller proportions of extractives and minerals. The products that can be obtained and derived from wood depend directly on its chemical composition. This work aimed to determine the contents of α-cellulose, holocellulose, hemicellulose, lignin, and the extractives in ethanol-benzene and ethanol of the wood of six Pinus patula trees. An analysis of variance was performed on the obtained data, followed by a multiple comparison of means (LSD, α = 0.05). The results indicated significant differences (p ≤ 0.05) in the chemical compounds among the six trees. On average, P. patula wood contained 67.93% holocellulose, 43.28% α-cellulose, 24.65% hemicellulose, 28.08% lignin, 2.30% ethanol-benzene extractives, 0.32% ethanol extractives, and 2.62% total extractives.

Potential use of bacterial strain in the genus Serratia to biocontrol fungal pathogens associated with defoliation on Pinus patula

ABSTRACT Pathogenic fungi that cause defoliation in different pine species, including Pinus patula, have been reported. The most common practice for controlling these pathogens is the use of fungicides, which have adverse environmental consequences. The objective of this study was to evaluate an alternative for pathogen control without affecting the ecosystem. Bacteria with antifungal activity obtained from forest soil were isolated and biochemically and molecularly identified for evaluation in biocontrol assays of fungi associated with defoliation under laboratory and field conditions. Two species of the genus Serratia, Serratia grimesii and S. proteamaculans, were identified as bacteria with antifungal activity. In vitro biocontrol was achieved by reducing the mycelium growth of fungi associated with diseased needles of P. patula: Alternaria alternata, Annulohypoxylon stygium, Botryosphaeria dothidea, Curvularia lunata, C. pseudobrachyspora, C. spicifera, C. trifolii, Daldinia sp., Daldinia eschscholtzii, Diplodia sapinea, Lophodermium indianum, and Myrmaecium rubricosum. The fungi in P. patula (Annulohypoxylon stygium and Daldinia eschscholtzii) decreased their damage by 82% and 77%, respectively, in the presence of Serratia under humid chamber conditions. In addition, the incidence of lesions (IL) and Disease Severity Index were significantly reduced under natural conditions. The results showed that biocontrol with bacteria of the genus Serratia is an alternative for the management of health in Pinus patula trees.

ALLOMETRIC EQUATIONS FOR BELOWGROUND BIOMASS AND CARBON CONTENT OF Pinus patula SCHL. et CHAM.

Allometric equations are essential tools for estimating biomass and carbon fixation in forest ecosystems. Published information is limited for belowground biomass of forests, mainly due to the methodological challenges of its determination. With the aim of contributing to the study of this important carbon store, in the present study allometric equations were developed for the estimation of belowground biomass of Pinus patula Schiede ex Schldl. et Cham. in its main natural distribution area: the states of Hidalgo, Puebla and Veracruz, Mexico. Seven Pinus patula trees with varying dimensions were selected and torn down at various sites; their diameter at breast height (DBH), total height (H), and crown diameter (CD) were measured. The totality of fine and coarse roots was extracted; the aboveground biomass was quantified by census, by sampling or by means of an allometric equation. Equations were developed for belowground biomass and carbon content, both total and by components, aswell as for individual root, both total and by components. The average root/ shoot ratio was 0.20 and the proportion of belowground in relation to the total biomass ranged from 12.1 to 21.2 %. The data on belowground biomass and carbon content at the tree level better fitted the Schumacher and Hall model that included both DBH and H as independent variables, which explained 99 % of the variation of belowground biomass and carbon. It was concluded that it is possible to use allometric equations to estimate the belowground biomass and carbon of Pinus patula trees from DBH and H, or even using only DBH.

The effect of planting density on the stem form of Pinus patula trees

In this study the effect of planting density on the stem form of Pinus patula trees was investigated. Four different spacing treatments of 403, 1 097, 1 808, and 2 981 stems per hectare (spha), and four stem form properties viz. stem deviation, taper, sinuosity and ovality, were assessed on the lower nine metres of the tree stem. The results showed that spacing treatment had a significant effect on all four stem form characteristics. Over the lower nine metres of the stem, the lower spacing treatments (403 and 1 097 spha) had mean stem deviations of 132.1 mm and 109.3 mm respectively, while the higher planting densities (1 808 and 2 981 spha) had mean stem deviations of 76.4 mm and 82.1 mm respectively. Sinuosity and taper also had a decreasing trend from 403 spha to 2 981 spha. Ovality, on the other hand, increased with increasing planting density and also increased with increasing height along the tree stem.

A method for determining knotty core sizes of standing Pinus patula trees based on tree ring sampling

The objectives of this study were to develop and assess a method of using tree ring measurements in standing pruned Pinus patula trees for modelling the knotty core of the pruned section of a tree and to assess variability in knotty core diameters in the tree stem. A total of 170 trees from 17 compartments on a wide variety of growth sites from the Mpumalanga escarpment in South Africa were selected and destructively sampled. We show that ring width measurements at breast height can be used to predict growth in the upper pruned section which in turn can be used to reconstruct the internal knotty core through the full pruned section of the log.Analysis of variation for the entire data set from ring width measurements showed that there was far greater variation in knotty core percentages (the percentage of diameter occupied by knotty core) between different compartments than within compartments. Within a tree, the knotty core percentages between three stem sections, 0.0–2.4m, 2.4–4.8m, and 4.8–7m, differed significantly. As expected the knotty core percentages were found to increase from the bottom section (49.1%) to the top section (65.4%).A comparison of the actual measured knotty core size and the modeled knotty core size of a sub-sample of trees showed only a modest relationship (R2=0.62). Reasons for this might be variability in pruning quality, inaccurate pruning records, nodal swellings, and the methodology used to measure the actual knotty core sizes.Knowledge of knotty core sizes can be used as a decision aid in the forest and forest products industry.

The variation of microfibril angle in South African grown Pinus patula and its influence on the stiffness of structural lumber

Reduction in the rotation ages of softwood saw-log plantations in South Africa is causing increased proportions of low stiffness sawn lumber at final harvest. It has been shown for some species that the microfibril angle (MFA) of the S2 layer of tracheids is strongly related to the modulus of elasticity (MOE) of wood, even more so than wood density, especially in wood formed during juvenile growth. The objectives of this study were to describe the variation in MFA in young Pinus patula trees and to determine the relationship between MFA and the dynamic MOE of sawn P. patula lumber. Thirty 16- to 20-year-old trees from six compartments from the Mpumalanga escarpment were processed into discs and lumber. The MFA, density and ring width were measured at two height levels using Silviscan 3. The average annual ring MFA varied between 7° and 29°; the pattern of variation depended mainly on height level and the ring number from the pith. The MFA in P. patula followed the same within-tree variation trends as in New Zealand-grown Pinus radiata but the average MFA was lower in absolute terms and differences between height levels were less pronounced. The MFA and density exhibited highly significant Pearson correlations of 0.73 and 0.70, respectively, with board dynamic MOE. A multiple regression model, which included MFA, density and ring width, explained 71% of the variation in the dynamic MOE of boards. A sensitivity analysis on the model showed that MFA and density had approximately similar influences on predicting the dynamic MOE of Pinus patula boards.

The prediction of the flexural lumber properties from standing South African-grown Pinus patula trees

Pinus patula is the most intensively planted conifer in the tropics and subtropics. The increased proportion of corewood that results when rotation ages of pine plantations are shortened has become a wood quality factor of growing concern worldwide. The purpose of this study was to develop empirically based models for predicting the flexural properties of the wood produced from relatively young P. patula trees. Models were based on the properties of standing trees, and their effectiveness was evaluated at board, tree, and compartment levels. Sample material was obtained from 170 P. patula trees, 16–20 years old, established in 17 compartments on the Mpumalanga escarpment of South Africa. Multiple regression models were developed, which managed to explain 68, 60, and 95 % of the variation in the dynamic modulus of elasticity (MOE) on individual boards, trees, and compartments levels, respectively. At compartment level, 80 % of the variation in the 5th percentile MOR value could be explained by the model. Sensitivity analyses showed that site index at base age of 10 years, acoustic time of flight, wood density, and ring width were influential variables in the MOE models. The models indicated that tree slenderness during early growth seems to play a major role in determining the dynamic MOE and MOR of lumber. This is in agreement with Euler’s buckling theory and the bending stress theory. The results from this study indicated that the MOEdyn and MOR of lumber can be accurately predicted on especially a compartment level. The predictive models developed can be used as management tools to improve operational decisions around tree breeding, silvicultural practices, and rotation ages.

Variation in strength, stiffness and related wood properties in young South African-grown Pinus patula

The objective of this study was to examine the variation in and intercorrelation among wood properties determining the suitability of 16- to 20-year-old South African-grown Pinus patula trees for structural timber. A total of 1 112 sawn boards from 340 logs, 170 trees and 17 different compartments were examined. Sawlogs were taken from two height levels from each tree. The mean modulus of elasticity measured on edge (MOEedge) was far below, and the mean twist higher than the limits set for structural grade softwood timber in South Africa. All the desirable properties for structural timber improved with distance from the pith with the exception of the fifth percentile value for modulus of rupture (MOR), which was higher at the pith than for the boards processed adjacent to the pith. Boards processed from the lower part of the stem were superior in most of the important properties compared to the properties higher up in the stem. The correlation between the dynamic modulus of elasticity (MOEdyn) and MOR of boards processed from the logs taken higher up in the stem was much weaker than in the case of the boards processed from the log taken from the lower part in the stem, suggesting that indirect (non-destructive) prediction of MOR decreased in reliability with increase in height in trees. A relatively strong negative correlation was found between the mean growth ring widths of the pith boards and the mean MOEdyn values per compartment, suggesting that slower initial growth in a compartment resulted in increased mean stiffness of boards from that compartment.

The structural grading of young South African grown Pinus patula sawn timber

In this study sawn timber from 16- to 20-year-old Pinus patula trees were obtained from a wide variety of sites along the Mpumalanga escarpment in South Africa. The objectives of this study were to assess the efficiency of the current visual and mechanical grading rules on this timber and to evaluate the potential of some indicator properties to be used as structural grading parameters on this resource. A large number of non-destructive measurements were performed on all samples (i.e. X-ray density scanning, acoustic frequency measurement, year-ring measurements and stiffness measurement) before it was destructively tested in bending and tension. The young P. patula timber tested in this study had good bending strength (MOR) properties with higher characteristic grade values than required. The timber, however, had low stiffness and did not comply with the SANS 10163-1 requirements for mean modulus of elasticity on edge (MOEedge) for any of the structural grades. Dynamic MOE (MOEdyn), calculated from acoustic frequency tests on the timber, was found to be the best single predictor of MOEedge, MOR and tension strength. Multiple regression analysis showed that a combination of MOEdyn, density and knot parameters can be used to improve the predictability of some of the strength and stiffness characteristics of the timber.

Discriminating the early stages of Sirex noctilio infestation using classification tree ensembles and shortwave infrared bands

The woodwasp Sirex noctilio is causing extensive damage to Pinus patula trees in the summer rainfall areas of South Africa. The ability to remotely detect S. noctilio infestation remains crucial for monitoring purposes and for the effective deployment of suppression activities. In this study, we evaluated whether random forest and boosting trees can accurately discriminate between healthy trees and the early stages of S. noctilio infestation using reflectance measurements in the shortwave infrared (SWIR). Three variable selection methods, namely, a filter, the random forest out-of-bag samples and a wrapper algorithm, were used to select the smallest subset of SWIR bands. The results show that random forest produces better classification results than the competing boosting trees for all three variable selection methods, even when noise is introduced into the SWIR bands and class labels. The ability of the bands centred at 1990, 2009, 2028, 2047 and 2065 nm to discriminate between healthy trees and the early stages of infestation could be explained due to the rapid physiological changes that occur as a result of the toxic mucus and a fungus that S. noctilio injects into the tree. Overall, the results are encouraging and show that there is a link between the selected SWIR bands and existing physiological knowledge, thereby improving the chances of detecting the early stages of S. noctilio infestation at a canopy or landscape level.

Discriminating the early stages of Sirex noctilio infestation using classification tree ensembles and shortwave infrared bands

The woodwasp Sirex noctilio is causing extensive damage to Pinus patula trees in the summer rainfall areas of South Africa. The ability to remotely detect S. noctilio infestation remains crucial fo...

Distribution of Diplodia pinea and its genotypic diversity within asymptomatic Pinus patula trees

Diplodia pinea (= Sphaeropsis sapinea) is an endophytic fungus and opportunistic canker pathogen of Pinus spp. The diversity of this fungus has been studied at broad geographic scales, but little is known regarding its population structure at smaller spatial scales such as within a single tree. This is despite the importance that diversity in a single tree might hold for understanding the biology of the fungus, especially the role of the endophytic or asymptomatic phase in disease development. Moreover there was not information regarding the distribution of the fungus within healthy trees and its persistence. The genotypic diversity of these isolates was investigated using microsatellite markers. Five polymorphic markers were developed and these were used together with eight previously developed markers and vegetative compatibility tests to study the genotypic diversity of D. pinea isolates. In this study, D. pinea was isolated for the first time in the well structured stems of healthy P. patula trees along with branches and cones. From a total of 44 isolates collected from five trees, 39 microsatellite haplotypes and 32 vegetative compatibility groups (VCG’s) were identified. The results indicate high genotypic diversity of D. pinea within individual asymptomatic trees which will lead to disease outbreak when trees are physiologically stressed.

The pulp and paper properties of Sirex noctilio infested and fire-damagedthermomechanically pulped, South African grown Pinus patula

Pinus patula is the softwood species most extensively planted in South Africa. However, large portions of these plantings are under threat from Sirex noctilio infestation and occasional forest fires. In this exploratory investigation, the effects of tree age, Sirex noctilio infestation and fire damage to wood from Pinus patula trees on their pulp and paper properties were evaluated. Pulp was produced using the thermomechanical pulping (TMP) process. The energy consumption required to pulp the different pulpwood materials was determined. Pulps were beaten for five different time periods to investigate the development of the fibre properties in response to increasing energy input. Paper properties such as burst, tear strength and breaking length were determined on handsheets manufactured from unbeaten and beaten pulps. Box and line plots and canonical variate analysis biplots were used to statistically analyse the data. It was found that the burst strength of paper produced from healthy trees was significantly higher than that from sirex-infested or fire damaged (burnt) trees. Similarly, the tear strength of paper from healthy and burnt trees was significantly better than from sirex-infested or young trees. No significant differences in breaking length were evident between the pulpwood materials and an increase in beating time did not lead to any improvements. From this study it can be concluded that wood from dead or dying, sirex-infested and young trees produced paper with consistently lower strength properties compared to wood obtained from healthy 12-year-old trees.

Variation in foliar water content and hyperspectral reflectance of Pinus patula trees infested by Sirex noctilio

The remote detection and quantification of symptoms associated with declining forest health is critical for the introduction of proper pest monitoring and control measures. Sirex noctilio, the Eurasian wood wasp, is one of the major pests responsible for declining forest health in pine forests located in KwaZulu-Natal, South Africa. Researchers have shown that stress induced by S. noctilio causes a rapid decrease in foliar water content, with the foliage of the tree changing from a dark green to a reddish brown hue. This study examined if the variation in foliar water content due to S. noctilio infestation can be remotely detected. Foliar water content and in situ hyperspectral measurements were obtained from Pinus patula trees experiencing varying levels of stress induced by S. noctilio. Subsequently, foliar water content was correlated to selected spectral variables consisting of known water absorption features, spectral indices and continuum-removed absorption features. Results showed that the variations in foliar water content across the varying levels of S. noctilio infestation were strongly linked to the variation in hyperspectral reflectance. Except for water absorption features located at 970 nm and 1200 nm, there was a strong correlation between the majority of the spectral variables and foliar water content. Of the spectral variables tested, the water index (WI) provided the strongest linear correlation (r = 0.84) with foliar water content. Ultimately, results obtained from this study provide the foundation for the detection and monitoring of S. noctilio infestations at a landscape level using airborne or spaceborne hyperspectral platforms.

A comparison of regression tree ensembles: Predicting Sirex noctilio induced water stress in Pinus patula forests of KwaZulu-Natal, South Africa

In this study we compared the performance of regression tree ensembles using hyperspectral data. More specifically, we compared the performance of bagging, boosting and random forest to predict Sirex noctilio induced water stress in Pinus patula trees using nine spectral parameters derived from hyperspectral data. Results from the study show that the random forest ensemble achieved the best overall performance (R2=0.73) and that the predictive accuracy of the ensemble was statistically different (p<0.001) from bagging and boosting. Additionally, by using random forest as a wrapper we simplified the modeling process and identified the minimum number (n=2) of spectral parameters that offered the best overall predictive accuracy (R2=0.76). The water index and Ratio975 had the best ability to assay the water status of S. noctilio infested trees thus making it possible to remotely predict and quantify the severity of damage caused by the wasp.

Effect of phosphorus and potassium fertiliser on stem form, basic wood density and stem nutrient content of Pinus patula at various stem heights

Summary The effect of silvicultural treatments on volume production, tree form, basic timber density and stem nutrient content with changes in tree height were investigated by destructively sampling 32 Pinus patula trees in a fertiliser × weed control trial at rotation age (15 y). Sixteen trees, covering the range of stem diameters, were selected from both the control (no fertiliser applied) and Split 80/80 (20 kg ha−1 of P and of K applied at planting as a spot application, followed by a broadcast application of 60 kg ha−1 of P and of K, after pruning at age 5 y) treatments. At 15 y of age the split application of 80/80 PK fertiliser increased the timber production by 32% (89.5 m3 ha−1) compared with the control. Fertiliser decreased basic wood density by 7% at ground level and by 5% over the entire stem. The nutrient concentration of N, P and K in the stemwood and stembark increased with an increase in stem height. The changes in nutrient content and basic wood density with tree height clearly indicate the need to sample at more than one height to obtain an accurate average or total value for each tree. The increased concentration of P in the wood, in addition to increased timber production, will result in a greater export of nutrients in harvested timber from compartments that receive fertiliser compared with those that do not.

Interactions amongst trees and crops in taungya systems of western Kenya

Lack of empirical data on the effects of the taungya system on establishment and early growth of softwood plantations have partly contributed to controversial decisions regarding the continued suitability of the system for plantation establishment in Kenya. This study examined effectiveness of taungya systems of forest plantation establishment using Cupressus lusitanica and Pinus patula trees with Zea mays (maize) as a test intercrop on two contrasting site types (deep and shallow soils) in Mt. Elgon forest, western Kenya . Four treatments were evaluated in each site: trees with or without weed control, trees intercropped with maize, and sole maize. Results showed that tree survival, growth and nutrient uptake, and maize growth and yield were higher in the deep soil site than the shallow site. The taungya system improved tree survival and growth, effects being greater in the deep than the shallow soil site. Both Cupressus lusitanica and Pinus patula trees had the same effects on maize growth and yield, reducing maize growth by 41–48% in the deep soil sites, and by 16–26% in the shallow site. Vector nutrient analysis and vector competition analysis of the treatment effects on growth and nutrient uptake of the trees and the maize crop suggested competition for N on the deep soils, but competition for K and P on the shallow soils. The study has demonstrated the applicability of graphical vector competition analysis in diagnosing tree–crop interactions in agroforestry.

Forest health and vitality: the detection and monitoring of Pinus patula trees infected by Sirex noctilio using digital multispectral imagery

The Eurasian woodwasp, Sirex noctilio, causes considerable tree mortality in commercial pine plantations in southern KwaZulu-Natal, South Africa. Broad-scale visual assessments of infestation provided by forest managers are currently used to measure forest health and vitality. The effectiveness of visual assessments is questionable because they are qualitative, subjective and dependent on the skill of the surveyor. Remote sensing technology provides a synoptic view of the canopy and thus offers an alternative to the conventional methods of monitoring forest health and vitality. In this study, high resolution (0.5 × 0.5m) digital multispectral imagery (DMSI) was acquired over commercial Pinus patula trees of varying age classes, which had been ground assessed and ranked on an individual tree crown basis using a severity scale. The severity scale was based on a hierarchy of decline symptoms that are visibly apparent on the infested tree and are represented in this study as the green, red and grey stages. A ...

RAPD assessment of clonal identity of somatic seedlings derived from vegetative shoot apices of mature Pinus patula trees

Randomly amplified polymorphic DNA (RAPD) analysis was used as a tool to assess the clonal identity of somatic embryo-derived plantlets from the parental vegetative shoot apices of three genotypes of Pinus patula. Twelve random decamer primers were successfully used to analyze genomic DNA from the parental field-grown plants and somatic embryo-derived plant material. A total of 158 scoreable fragments were amplified with an average of 4.39 bands per primer per lane. Of these, 100 were monomorphic and 58 were polymorphic (36.7% polymorphism). The results indicate that RAPD markers can be applied successfully as a rapid, simple and cheap tool for the establishment of genetic identity between donor parental field grown plants and micropropagated material.

Storability and germination of sodium alginate encapsulated somatic embryos derived from the vegetative shoot apices of mature Pinus patula trees

Storability and germination of sodium alginate encapsulated somatic embryos derived from vegetative shoot apices of mature Pinus patula trees were tested on half strength DCR basal medium without growth regulators. The germination percentage of encapsulated somatic embryos was affected significantly by the concentration of sodium alginate and the duration of exposure to calcium chloride. Somatic embryos encapsulated with 2.5 sodium alginate dissolved in DCR basal salts gave significantly higher germination (89) than other treatments. Short (5 min) incubation of the alginate encapsulated embryos in calcium chloride solution proved to be the best encapsulation procedure and the embryos subsequently gave the highest germination (89). Synthetic seeds could be stored at 2 °C for 120 days without a reduction in germination as opposed to non-encapsulated somatic embryos which showed only 9 germination after 20 days at 2 °C. Germinated synthetic seeds produced normal plantlets. This study reports for the first time the storability of encapsulated somatic embryos generated from vegetative shoot apices of mature Pinus patula trees. This has potential for application in forestry.