Bark Diameter Research Articles

An additive model system for heartwood, sapwood and bark diameter – A working example in Pinus koraiensis Siebold & Zucc. plantations

Accurate estimations of a tree stem’s heartwood diameter (HD), sapwood width (SW), bark thickness (BT) and diameter outside bark (DOB) are essential for volume and biomass calculations, forest management, and optimal timber production. Understanding these components also provides valuable insights into the ecological health and functioning of forest ecosystems. The additive model system, enhanced by machine learning algorithms, offers new tools for estimation. We constructed parametric taper models and nonparametric multilayer perceptron models to compare the accuracy of HD, SW, BT, and DOB estimates based on 3199 upper stem diameter measurements obtained from 103 sample Pinus koraiensis Siebold & Zucc. trees in Northeast China. In the context of the additive model system for tree stem internal components, we utilized nonlinear seemingly unrelated regression (NSUR) as a parametric method and multitask learning (MTL) as a nonparametric method. In the comparison of additive model systems, MTL (nonparametric) performed better than did NSUR (parametric) by improving the accuracy and generalizability of the stem and internal component estimates. The coefficient of determination (R2) for DOB, HD, SW, and BT increased by 0.31%, 1.39%, 4.21%, and 4.31%, respectively. Based on these results, we conclude that the MTL provides a valid option for improving HD, SW, BT, and DOB and enhancing the volume prediction of stem components.

Post Debarking Response of <i>Prunus africana</i> (Hook. F) Kalkman (<i>Rosaceae</i>) Trees at Two Exploitation Sites in North Kivu (Eastern Democratic Republic of Congo)

Prunus africana is a species of great economic, medicinal and ecological importance. Due to its multiple uses, unsustainable exploitation methods and low regeneration capacity in tropical rainforests, this species is threatened with extinction. Present and exploited in the eastern part of DR Congo, knowledge of the dynamics of post-bark regeneration of Prunus africana remains fragmentary and poorly known. In North Kivu province, this species thrives in both afromontane forest and lowland tropical rainforest habitats. In order to contribute to the rational and sustainable exploitation of Prunus africana in this province, this paper was carried out with the objective of contributing to the knowledge of the dynamics of the regeneration of post-harvest bark of Prunus africana in two exploitation sites (low and high altitude). To achieve this objective, the inventory was conducted on 16 plots of 25 hectares each, with 8 plots per site. Dendrometric parameters (diameter at breast height (DBH), total tree height) and tree growth and regeneration parameters, i.e., stem bark thickness of the unharvested and harvested portions of the trees (bark reconstitution) were measured. A total of 716 barked stems of Prunus africana in 2016 in 25 hectares constituted the study sample. Results show that sites do not influence diameter at breast height of P. africana trees (p > 0.05) or total tree height. The bark diameter of harvested trees and the bark diameter of unharvested trees varied significantly by site (p 0.05). In contrast, the annual growth rate of bark differed with altitude; the highest rate was observed in trees growing at high altitude (2.97 ± 0.9 mm/yr) compared to 2.23 ± 0.74 mm/yr at low altitude. In view of these results, this study indicates that a half-rotation of 7 years could allow an effective reconstitution of the bark of Prunus africana at the second passage on the remaining side of the same stem.

Machine learning and regression models to predict multiple tree stem volumes for teak

The quantification of a stand’s wood stock is one of the most important procedures for Tectona spp. (teak) management. An optimal method for estimating tree volume must accommodate the variation of the data collected in the inventory. This study evaluated alternative methods to estimate the volume on stems of teak trees. We cut and measured the outside bark, inside bark, and heartwood diameters at heights of 0.1, 0.5, 1.5 m and every meter thereafter until the minimum outside bark diameter reached 3 cm, using 180 trees of ages 3 to 12 years. We tested two approaches (A1 and A2) to estimate stem volumes of the outside bark, inside bark, and heartwood (v ob, v ib and v hw, respectively): modelling the tree volume in A1, and the taper model in A2, with the techniques of regression, artificial neural network (ANN) and support vector regression (SVR). In addition, we obtained the percentages of heartwood, sapwood and bark in the stem. The accuracies of the estimates were evaluated using bias, correlation and root-mean- square error (RMSE). Validation was made for the outside bark, inside bark and heartwood volumes, and the outside bark, inside bark and heartwood diameters, from the taper models. In A1, the ANN technique more accurately predicted v ob and v ib, with RMSE% values of 18.88% and 18.54%, respectively; for v hw, the regression technique was more accurate, with RMSE% equal to 26.87%. In A2, the regression technique obtained the highest precision in the prediction of v ob, v ib and v hw, with RMSE% values of 13.99%, 13.31% and 26.50%, respectively. Approach A2 showed more accurate results compared with A1 for predicting the multiple volumes of teak trees with the three tested techniques.

Morpho-phenetical study of high yielding tossa jute variety BJRI Tossa Pat 7 (MG-1) for bast fibre yield and qualities

Background and aim of the studyTossa jute (Corchorus olitorius) is a natural fibre crop produces good quality fiber having great demand for industrial uses. High yielding tossa jute variety is very important in Bangladesh. Materials and methodsBangladesh Jute Research Institute (BJRI) has developed a new tossa jute variety (BJRI Tossa Pat 7) through pure line selection (PLS) from another pre-released variety named OM-1 during 2017. The new variety was evaluated for fiber yield and attributing phonological traits through comparing with another pre-released variety named BJRI Tossa Pat 5 (O-795) in RCB design at six locations during 2015–2018. ResultsDistinct morphological traits i.e. ovate lanceolate glossy leaves; full green plant were found in MG-1 and stem & stipule red; ovate lanceolate leaves in O-795. MG-1 showed higher fiber yield (3.39–3.40 t ha−1) where, O-795 showed 3.10–3.22 t ha−1 as means of their maximum performances for three years at both farmers' plots and research fields. MG-1 gave higher plant height, base diameter, fiber yield than O-795 at both research stations and farmers’ fields. Even after sowing at 10–15 March, MG-1 gave late flowering; lower leaf size, leaf angle, green leaf biomass and node number; maximum inter-nodal length, bark diameter, bark thickness and fiber bundle cells; and finally golden bright quality fiber than O-795. If both varieties were sown at 2nd to 3rd week of March, and harvested at 110 days old, MG-1 gave 5–7% higher fiber yield than O-795. ConclusionUndoubtedly, MG-1 is a good tossa jute variety for its fiber yield and quality than pre-released varieties. RecommendationMG-1 having good fiber yield would be used for commercial cultivation by the farmers to contribute to the national economy.

Modelling climate effects on diameter growth of red pine trees in boreal Ontario, Canada

The climate is changing and these changes may affect tree growth. Diameter growth models are one of the essential inputs for many growth and yield projection systems. Therefore, diameter growth models that can be used to estimate inside bark diameter at breast height (DBH) for red pine plantations in a changing climate were developed. One hundred and fifty red pine (Pinus resinosa Ait.) trees were sampled from 30 even-aged monospecific plantations (sites) (5 trees/site) across Ontario, Canada. Stem analysis data collected from these trees was used to develop and evaluate the growth models using a mixed effects modeling approach. Site and climate effects on diameter growth were examined by incorporating site and climate variables in the models. Including climate variables improved the fit statistics.Inside bark DBHs were predicted for 4 geographic areas of Ontario for the period 2021 to 2080. Three emissions trajectories known as representative concentration pathways (RCPs), each reflecting different levels of heat at the end of the century (i.e., 2.6, 4.5, and 8.5 W m−2), were evaluated. At the end of the 2021 to 2080 growth period, projected diameters were wider by 11% and 23% for trees in the southeastern and southwestern parts, respectively, and narrower by 6% for those in the central west part of Ontario (under all climate change scenarios relative to those under a no change scenario). However, no pronounced difference in projected diameters was evident for trees in the far west part of the province regardless of climate change scenario (relative to the no change scenario). In the absence of climate data, the model fitted without climate variables can be used to estimate inside bark DBH.

A Taper Equation for Loblolly Pine Using Penalized Spline Regression

Abstract Stem profile needs to be modeled with an accurate taper equation to produce reliable tree volume assessments. We propose a semiparametric method where few a priori functional form assumptions or parametric specification are required. We compared the diameter and volume predictions of a penalized spline regression (P-spline), P-spline extended with an additive dbh-class variable, and six alternative parametric taper equations including single, segmented, and variable-exponent equation forms. We used taper data from 147 loblolly pine (Pinus taeda L.) trees to fit the models and make comparisons. Here we show that the extended P-spline outperforms the parametric taper equations when used to predict outside bark diameter in the lower portion of the stem, up to 40% of the tree height where the more valuable wood products (62% of the total outside bark volume) are located. For volume, both P-spline models perform equal or better than the best parametric model, with taper calibration, which could result in possible savings on inventory costs by not requiring an additional measurement. Our findings suggest that assuming a priori fixed form in taper models imposes restrictions that fail to explain the tree form adequately compared with the proposed P-spline.

Effect of thinning and fertilizer on growth and allometry of Eucalyptus marginata

Jarrah (Eucalyptus marginata) forest is one of the most widespread native forest types of south west Western Australia (SWWA) and provides timber, firewood, wildlife habitat, water production, catchment protection and recreation. To inform management aimed at optimizing these values, a thinning trial in even aged regrowth forest was commenced in 1965. A second thinning and N and P fertilizer treatment was applied in 1986. The effect of thinning and fertilizer on tree and stand level growth and allometry was evaluated. Thinning resulted in higher values of under bark diameter at breast height (DBHUB) and tree height, and lower values of height diameter ratio (HDR), stand basal area under bark (BAUB) and stem number per unit area. Growth of DBHUB increased with a decrease in stand density. Growth of stand BAUB peaked at intermediate stand densities. Fertilizer increased growth in DBHUB and stand BAUB. Height growth was significantly greater in thinned plots. Thinning had a significant effect on the allometric relation between diameter at breast height over bark (DBHOB) and each of height, HDR and crown width (CW) while fertilizer had a significant effect on the allometric relation between DBHOB and each of height and HDR. Height and CW increased with an increase in DBHOB but HDR decreased. Larger sized trees resulting from thinning and addition of fertilizer are likely to provide a higher volume of timber, firewood, fruits (important food for threatened cockatoos), and improved visual amenity. As thinning had a positive effect on diameter and height growth and self-thinning in jarrah is relatively low (0.20% yr−1), thinning may be a valuable management tool to accelerate development of larger trees which can be beneficial for both timber production and conservation.

ALTERNATIVES TO ESTIMATE THE VOLUME OF INDIVIDUAL TREES IN FOREST FORMATIONS IN THE STATE OF MINAS GERAIS, BRAZIL

The objective of this study was to compare different alternatives to estimate the stem volume of individual trees in four different forest formations in the Minas Gerais state, Brazil. The data were obtained in a forest inventory procedure performed by the Minas Gerais Technological Center Foundation. The stem volumes were computed by the Smalian expression up to the outside bark diameter equal to 4 cm. The volume data of outside bark, diameters (DBH) and total heights were used to fit a Schumacher and Hall equation for each forest formation, considering the structures of the linear fixed and mixed models. Next, 100 Multilayer Perceptron artificial neural networks (ANN) were trained in a supervised manner. In addition, we evaluated eight support-vector machine regression (SVMR). The criteria to evaluate the performance of all the alternatives studied were: the correlation between the observed and estimated volumes, the square root of the mean square error and the frequency distribution by percentage relative error class. After the analyzes, all the alternatives were verified to estimate the volume of the individual trees in the different forest formations. Although the alternatives presented close statistics in the validation process, the graphical analysis of the error distribution showed greater precision of the estimates of the mixed linear models for the four formations. Given the results, it is concluded that there is no absolute superiority of one alternative over the others, and that all of them should be evaluated to find the one which best describes or explains the dataset.

Elucidation of Genotypic Variability, Character Association, and Genetic Diversity for Stem Anatomy of Twelve Tossa Jute (Corchorus olitorius L.) Genotypes.

Background and Aims Anatomy of twelve tossa jute genotypes were performed for the variability, heritability, and genetic advance based on yield attributing six anatomical traits. Materials and Methods The experiments were carried out in field and laboratory including 12 tossa jute genotypes followed by RCB design in JAES, Manikganj, and Bangladesh Jute Research Institute, Dhaka, Bangladesh, during 2019-2020. Hypothesis. The tested genotypes were expected to perform better than controls in respect of anatomical characters contributing to fiber yield in tossa jute plants. Results Five genotypes, i.e., Acc. 1318, Acc. 1306, JRO S1, O-412-9-4, and O-0512-6-2 providing good results for the total fiber bundle area, trapezoid number, bark diameter, area of trapezoid, and bark thickness per transverse section in the anatomy of jute plants depicting the more variability (P > 0.01) as well as the possibility of tossa jute varietal development. These morphological and anatomical traits showing highly significant association (∗∗) with one another and coupled with high genetic and phenotypic variance components; high heritability; high and moderate genetic advance and higher divergence in clustering (D2), and PCA would be used as criteria for selection and improvement for fiber yield of tossa jute. Conclusions The high variation and divergence for anatomical characters may be considered an effective selection method of genotypes for higher fiber yield comparing with controls. The genotypes, i.e., Acc. 1318, Acc. 1306, JRO (segregate), O-412-9-4, and O-0512-6-2 with good anatomical traits related to fiber yield could be used as parents in breeding program as well as direct variety development.

Analyses of Genetic Variability, Character Association, Heritability and Genetic Advance of Tossa Jute (<i>Corchorus olitorius</i>) Genotypes for Morphology & Stem Anatomy

Background and aims: Investigation was carried out to estimate the variability, heritability, genetic advance for fiber yield based on yield attributing morpho-anatomical traits of tossa jute in field and laboratory. Materials & Methods: The experiments were carried out using 12 tossa jute genotypes followed by randomized complete block design in five jute research regions (Rangpur, Faridpur, Jessore, Manikganj districts and Bangladesh Jute Research Institute head office, Dhaka) of Bangladesh during 2019-20. Hypothesis: The tested genotypes were expected to perform better for fiber yield than control varieties. Results: The jute genotypes i.e. Acc. 1318, Acc. 1306, (JRO S1), O-412-9-4, O-0512-6-2 providing good results for plant height, base diameter, green weight and dry fiber yield in morphological study; and total trapezoidal area per transverse section, number of trapezoid per T. section, bark diameter, bark thickness in anatomical study depicting the more variability as well as possibility of tossa jute development. These morphological and anatomical traits showing significant association with one another, and coupled with high genetic and phenotypic variance-covariance components; high heritability; high & moderate genetic advance and genetic advance in percent of mean would be used for selection of jute genotypes regarding the jute crop improvement for fiber yield. Conclusions: The high variation for morphological and anatomical characters may be considered as effective method for screening of jute genotypes for higher fiber yield comparing with control varieties. The genotypes i.e. Acc. 1318, Acc. 1306, (JRO S1), O-412-9-4, O-0512-6-2 with good morphological and anatomical traits related to yield could be used as parents in breeding program as well as jute variety development.

Comparison of Fixed- and Mixed-Effects Approaches to Taper Modeling for Scots Pine in West Poland

Diameter measurements along the stem, which are the basis for taper models, usually have a hierarchical structure. Mixed-effects models, where fixed and random effects are distinguished, are a possible solution for this type of data. However, in order to fully absorb the potential of this method, random effects prediction, which requires additional measurements (diameter along stem), is recommended. This article presents a comparison of various fitting methods (mixed- and fixed-effects model approaches) of the variable-exponent taper model created by Kozak for determining the outside bark diameter along the stem and predicting the tree volume of Scots pine trees in west Poland. During the analysis, it was assumed that no additional measured data were available for practical use; therefore, for the mixed-effects model approach, fixed effects prediction without random effects was applied. Both fitting strategies were compared based on modeling and an independent validation data set. The comparison of mixed- and fixed-effects fitting strategies for the diameter along the stem indicated that the taper model fitted using the mixed-effects model approach better fit the data. Moreover, the error rate for the total tree volume prediction for the independent data set was lower for the mixed-effects model solution than for the fixed-effects one.

Agronomic efficiency of ‘Cantaloupe’ melon under different water blades and organic fertilization

The objective of this study was to evaluate the effect of different irrigation blades on the presence and absence of biofertilizer on the agronomic performance of the ‘Cantaloupe’ melon in the Paraíba backwoods. The work was conducted under field conditions in the Agroecology Sector, belonging to the State University of Paraíba (UEPB), Campus IV. The experimental design was a randomized block using four irrigation blades (60, 80, 100 and 120% - ET0, (mm day-1)) with presence and absence of biofertilizer replicated six times. The following variables were evaluated: main branch length, leaf area, number of leaves, phytomass aerial part, pulp diameter, soluble solids, bark diameter, number of seeds per fruit, seed weight per fruit and weight of 100 seeds. The irrigation blade of 120% of ET0 promoted greater growth and development since biofertilizer application provided a greater number of seeds per fruit and weight of 100 seeds, there was no interaction between the factors studied in both variables evaluated in the Cantaloupe melon.

EVALUATION OF NON-LINEAR TAPER EQUATIONS FOR PREDICTING THE DIAMETER OF EUCALYPTUS TREES

ABSTRACT This study aims to evaluate non-linear stem taper models for predicting the pre-commercial diameter of eucalyptus trees and to analyze the effect of genotype on stem taper. The treatments comprise three different genotypes of Eucalyptus sp. in a 3 × 3 m plantation spacing. Seventy sample trees aged 10 years were felled for each treatment. The outside bark diameter measurements were taken at 0.5 m; 1.0 m; 1.5 m; 2.0 m, and then at intervals of 2.0 m till the top of the stem. Four non-linear models were evaluated, namely, the sigmoid model of Garay (1979), the variable exponent model of Kozak (1988), the segmented model of Max and Burkhart (1976), and the compatible model of Demaerschalk (1972). The performance of the models was assessed using the following statistical validation methods: correlation coefficient, standard error of estimate, mean bias, bias variance, root mean squared error, and mean absolute deviation. Graphical analysis of residues was used to evaluate the accuracy and precision of the estimates. Compared with other models, the variable exponent model of Kozak (1988) best described the stem profile, and predicted the total volume of the trees. The identity test showed that the stem profile is affected by the genotype.

Allometry of Sapwood Depth in Five Boreal Trees

This paper analyzes sapwood variability and allometry within individuals of Populus tremuloides, Pinus contorta, Pinus banksiana, Picea mariana, and Picea glauca. Outside bark diameter at breast height (DBH) and sapwood depth (sd) in four cardinal directions were measured in individuals in stands in Alberta and Saskatchewan, Canada. The microscopical analysis of wood anatomy was used to measure sd, and the error associated with the measures was observed. Sapwood allometry analyses examined the influence of DBH on sd and on sapwood area (SA). All species were observed to have varying sapwood depths around the trunk with statistical analyses showing that Pinus banksiana has a well defined preference to grow thicker in the North-East side. The largest sd values were observed for the Populus tremuloides set. Unlike Populus tremuloides and Picea glauca, for the species Pinus contorta, Pinus banksiana, and Picea mariana, incremental growth in DBH does not directly drive sapwood growth in any direction. For these three species, SA increases only because of increases in DBH as sd remains nearly constant. These results show that sapwood depth and sapwood area seem to behave differently in each studied species and are not always proportional to the tree size as is normally assumed.

Corticolous lichens as environmental indicators of natural sulphur emissions near the sulphur mine El Vinagre (Cauca, Colombia)

AbstractThe aim of this study was to evaluate the spatial effect of a natural source of sulphur pollution on the species diversity, richness and distribution of corticolous lichens in a páramo zone at the mine ‘El Vinagre’ (Puracé, Cauca, Colombia). Three zones at different distances from the pollution source were established: zone 1 with a high degree of contamination, a potentially mildly affected or transitional zone 2, and a zone 3 free of disturbance. In each zone, 10 phorophytes ofWeinmannia microphylla(Cunoniaceae) were sampled, and all lichens in a 150 cm vertical transect 50 cm above the ground were collected and identified. Phorophyte parameters were measured (bark pH and diameter at breast height) and the samples were georeferenced. In order to evaluate the impact on lichens, non-metric multidimensional scaling (NMS) and indicator species analysis were carried out. ANOVA and Spearman correlations were performed to assess the relationships of environmental and tree variables between zones and with lichen community structure. The index of atmospheric purity (IAP) and the environmental rating factor (FCA) were evaluated for the three zones. In total, 104 lichen species were recorded, of which 72 were identified to species, 17 to genus, and four to family; 11 samples could not be identified. NMS clustered samples according to zone and the main axis which were correlated with bark pH and distance from pollution source. We found eight indicator species characterizing different zones, and four marginally significant indicator species. Using the IAP, we established three isocontamination areas, with zones 2 and 3 classified as more or less pristine zones and zone 1 as a polluted zone (supported by bark pH as a proxy for current pollution). Diversity was lowest in zone 1, closest to the pollution source, and lichen species composition differed between zones. Differences between lichens in zones 2 and 3 appear mostly unrelated to the current pollution source and might be more related to historical differences in impact from a 20-year-old pollution source.

Probabilidad de mortalidad de arbolado joven de Pinus hartwegii Lindl. con afectaciones por fuego en el Parque Nacional Izta-Popo

A nivel mundial se realizan grandes esfuerzos para determinar el efecto del fuego en la mortalidad de especies arbóreas como las del género Pinus. En este trabajo se evaluó la influencia del fuego en la probabilidad de mortalidad del arbolado joven de Pinus hartwegii en el Parque Nacional Izta-Popo, área natural protegida del centro de México. Los efectos de un incendio de mediana a alta intensidad ocurrido en marzo del 2013, una quema prescrita de baja intensidad realizada en abril del mismo año y un área testigo sin presencia de fuego reciente se valoraron y compararon. Los resultados mostraron que 18 meses después de aplicados los tratamientos, la mortalidad del arbolado en el área con quema prescrita fue de 13 %, mientras que en el área incendiada y testigo fue de 28 y 4 %, respectivamente. Se obtuvieron seis modelos logísticos para predecir la mortalidad; el porcentaje de copa dañada, la altura de cicatriz y el diámetro normal con corteza fueron las variables significativas (P < 0.05) de predicción. Los resultados sugieren que la disminución en la capacidad fotosintética y en el transporte de nutrimentos, asociados al daño de la copa y al cámbium, están estrechamente ligados con la probabilidad de mortalidad.

Dynamics of leaf gas exchange, chlorophyll fluorescence and stem diameter changes during freezing and thawing of Scots pine seedlings.

Boreal trees experience repeated freeze-thaw cycles annually. While freezing has been extensively studied in trees, the dynamic responses occurring during the freezing and thawing remain poorly understood. At freezing and thawing, rapid changes take place in the water relations of living cells in needles and in stem. While freezing is mostly limited to extracellular spaces, living cells dehydrate, shrink and their osmotic concentration increases. We studied how the freezing-thawing dynamics reflected on leaf gas exchange, chlorophyll fluorescence and xylem and living bark diameter changes of Scots pine (Pinus sylvestris L.) saplings in controlled experiments. Photosynthetic rate quickly declined following ice nucleation and extracellular freezing in xylem and needles, almost parallel to a rapid shrinking of xylem diameter, while that of living bark followed with a slightly longer delay. While xylem and living bark diameters responded well to decreasing temperature and water potential of ice, the relationship was less consistent in the case of increasing temperature. Xylem showed strong temporal swelling at thawing suggesting water movement from bark. After thawing xylem diameter recovered to a pre-freezing level but living bark remained shrunk. We found that freezing affected photosynthesis at multiple levels. The distinct dynamics of photosynthetic rate and stomatal conductance reveals that the decreased photosynthetic rate reflects impaired dark reactions rather than stomatal closure. Freezing also inhibited the capacity of the light reactions to dissipate excess energy as heat, via non-photochemical quenching, whereas photochemical quenching of excitation energy decreased gradually with temperature in agreement with the gas exchange data.

Contrasting sapling bark allocation of five southeastern USA hardwood tree species in a fire prone ecosystem

Fire affects numerous aspects of plant growth and anatomy, particularly in those species adapted to persist in fire‐prone environments. A key aspect of tree survival is rapid accumulation of protective bark within fire return intervals. We compared bark accumulation in five co‐occurring hardwood species within a longleaf pine (Pinus palustris) ecosystem in the mountains of northeastern Alabama, USA. Sampled species included blackjack oak (Quercus marilandica), sand hickory (Carya pallida), common persimmon (Diospyros virginiana), rock chestnut oak (Quercus montana), and red maple (Acer rubrum). Using bark thickness and inside bark diameter measurements taken at 20‐cm intervals along the main stem of saplings (average age 4–5 years) we found that, while average wood diameter did not differ across species, significant differences occurred in the ratio of bark to wood. Bark comprised over half (bark:wood = 0.55) of the basal diameter of blackjack oak, which was 3×, 4×, and 6× greater than the bark:wood ratio of sand hickory and rock chestnut oak, common persimmon, and red maple, respectively. Bark taper revealed that while other species allocated similarly to bark along the length of their stem, blackjack oak allocated much more at its base (in the flaming zone) and relatively less as height increased. Red maple, a commonly cited invader during fire‐free intervals, invested the least in bark thickness and, with rock chestnut oak, had an average height and height:diameter ratio significantly greater than blackjack oak and all other species, respectively. These results confirm the adaptive importance of bark thickness to enhancing species survival in frequent fire regimes.

Study on Effect of Tree Diameter, Height and Acid Treatment on Trace Elements and Yield of Gum Extracted From Acacia Nilotica (Babul)

The tapping and extraction of gum was carried out at Khadiya Camp Site, DungarDakshin Range, Forest Department, Junagadh with the cooperation of Forest Department, Junagadh. The trees of desired diameter ( 20 cm) have been selected on which an incision was made at predefined tapping ( 80 cm ) height as per treatment by an axe. The cut was of about 40 cm in width and treated with different concentration of H2SO4 (0, 40, 60%) to find out effect on yield and trace elements. The gum accumulated in width of cut was collected after 25 days once oozing started. The purified gum was analyzed for trace elements like copper, ferrous, manganese and zinc. From the study it was concluded that the maximum gum yield and trace elements was found from the Acacia tree at the bark diameter should be more than 20 cm and tapping height either more than 80 cm or less than 40cm from ground level. It was also found that H2SO4 treatments gave significant effect on gum yield and trace elements

Modeling Diameter Distribution of the Tropical Rainforest in Oban Forest Reserve

Diameter distribution model was developed for tropical rainforest of Oban Forest Reserve. Multistage sampling technique was adopted for the study. The sampling procedure was made up of primary, secondary and tertiary sampling units. A total of 808 trees were measured in 14 tertiary sample plots (40m x 50m). Tree outside bark diameter at breast height (dbh) data, were measured for tree species with dbh ≥ 10 cm within the tertiary sampling units. Data were analysed on several probability density function (pdf), then ranked based on Kolmogorov smirnov, Anderson darling and Chi-Square. The best six distributions (Beta, Burr 4P, Gamma 3P, Johnson S B , Lognormal and Weibull 3P) were further tested with Kolmogorov smirnov (D) and Chi-Square () for fitting the diameter data. The results indicated that there are more trees in the lower diameter class than the upper diameter class. Weibull 3P and Johnson S B distribution were adjudged more flexible when tested with Kolmogorov smirnov and Chi-Square respectively. The reason is because their calculated values (Weibull 3P = 0.02397 and Johnson S B = 3.8161) were the lowest values and less than the tabulated values (D = 0.05 and () df 9 = 16.919 respectively) at p ≥ 0.05. This implies the data followed the specified distribution and that Weibull 3P and Johnson S B can appropriately provide a better fit for the diameter data in Oban Forest Reserve.