diameter classes
Recently Published Documents


TOTAL DOCUMENTS

127
(FIVE YEARS 38)

H-INDEX

14
(FIVE YEARS 2)

2022 ◽  
Author(s):  
K. A Sreejith ◽  
M. S Sanil ◽  
T. S Prasad ◽  
M. P Prejith ◽  
V. B Sreekumar ◽  
...  

Tropical forests have long been accepted for their productivity and ecosystem services on account of their high diversity and stand structural attributes. In spite of their significance, tropical forests, and especially those of Asia, remain understudied. Until recently, most forest inventories in Asia have concentrated on trees 10 cm in diameter. Floristic composition, plant species diversity, above-ground biomass, basal area, and diversity were investigated across different life forms and two-diameter classes in a large-scale 10-ha plot, in the undisturbed tropical seasonal rain forest of Southern Western Ghats, Kerala, India. The regeneration pattern of the study area was examined by evaluating fisher's alpha and IVI (Important Value Index) across three layers of vegetation (seedling, sapling, and tree). Within the plot, we recorded 25,390 woody plant species ≥1 cm dbh from 45 families, 91 genera, and 106 species. Plant density was 2539 woody individuals per hectare, with a basal area of 47.72 m2/ha and above-ground biomass of 421.77 Mg/ha. By basal area, density, and frequency, the Rubiaceae, Sapotaceae, and Malvaceae families were the most important. Small-diameter trees (1 cm ≤ dbh ≤10 cm) were found to be 78 percent of the total tree population, 20.2 percent of the basal area, and 1.4 percent of the aboveground biomass. They also possessed 6 percent more diversity at the family level, 10% more diversity at the genus level, and 12% more diversity at the species level than woody individuals under 10 cm dbh. Woody individuals of treelets life form and small-diameter classes were much more diverse and dense than the other groups, indicating that results based only on larger canopy trees and larger diameter class maybe not be an appropriate representation of the diversity status of a particular tropical forest type. The lower density of individuals in the initial girth class indicates the vulnerability of the forest system to anthropogenic, natural disturbance and a changing climate. Reduce the minimum diameter limit down to 1 cm, in contrast to 10 cm limit used in most of the evergreen forest inventories, revealed a high density and diversity in the lower stories.


Author(s):  
Jamilie Brito De Castro ◽  
Renisson Neponuceno De Araújo Filho ◽  
Victor Casimiro Piscoya ◽  
Cristiane Maria Gonçalves Crespo ◽  
Renata de Oliveira Fernandes ◽  
...  

The present work aimed to quantify the concentrations and biomass stock of fine andthick roots, in three areas in the municipality of Capitão Poço-PA, Brazil. The areas used were degraded area, recovery area and native forest. For soil sampling, 24 trenches were opened, measuring 70 x 70 x 100 cm. In these trenches, soil samples were taken at depths 0-10, 10-20, 20-30, 30-40, 40-50, 50-60, 60-80 and 80-100 cm and sieving was carried out.All roots and other underground plant structures that remained in the sieve were collected by manual collection. The roots were separated into two diameter classes: fine roots ≤ 5 mm and thick roots > 5 mm, kiln dried and weighed.In the analysis, higherconcentrationsofthickand fine roots were observed in an area of native forest at depths of 0-10 and 10-20 cm. In the areas analyzed in this study, the root density in the topsoil of 0-10 cm was mainly composed of fine roots.In the three areas analyzed in this study, it was observed that from a depth of 10-20 cm there were decreases in theconcentrationsofthick roots. The area under recovery approached the area of native forest in the concentration of fine roots, demonstrating possible improvements in soil quality and recovery is probably actually taking place.


IAWA Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Emilio Estrada-Ruiz ◽  
Hugo I. Martínez-Cabrera ◽  
Imelda P. García-Hernández

Abstract We describe two new fossil woods from the San Carlos Formation (Upper Cretaceous), Chihuahua State, Mexico. The first wood resembles the fossil genus Metcalfeoxylon in having solitary vessels, scalariform perforation plates, vessel-ray parenchyma pits of similar size as the intervessel pits, axial parenchyma apotracheal diffuse and diffuse in aggregates, and heterocellular multiseriate rays with long, uniseriate tails. The second wood is a new fossil genus, and it is characterized by having diffuse porous wood, vessels predominantly solitary, vessel outlines oval and tending to be of two diameter classes, simple perforation plates, minute alternate intervessel pits, vessel-ray parenchyma pits similar to intervessel pits in size and shape, vasicentric tracheids, non-septate fibers, homocellular rays, and exclusively uniseriate and biseriate rays. This combination of features supports its placement in Myrtales (?Myrtaceae), in a new fossil-genus named Lazarocardenasoxylon. These two new records provide more information about the floristic composition of the Late Cretaceous flora of the San Carlos Formation and its relationship with those from the southern USA. However, a definitive picture of the floristic relationship of these Cretaceous floras of northern Mexico and southern USA remains elusive.


2021 ◽  
Vol 8 (2) ◽  
pp. 213-227
Author(s):  
Dani Pamungkas ◽  
Aziz Umroni ◽  
Nurhuda Adi Prasetyo

Screw tree (Helicteres isora) is a shrub species (Fam: Malvaceae) with 1.5–4 m in height and  with multi-main trunks up to 9–12. In Indonesia, kayu ules has been used as a traditional medicine, known as jamu, and has been commercialized. In order to cultivate this species, vegetative propagation is likely promising compared to the generative propagation since seed viability is low and cannot be stored for longterm. Nevertheless, there is a lack of information on which diameter classes, media types and light intensities would give the best result for vegetative propagation. This research aimed to obtain information on which diameter classes and media that were suitable for kayu ules stem cutting propagation and to what degree the light intensity would be best for the growth of the seedlings of kayu ules. Three diameter classes and four media types were employed in a  complete random design under the greenhouse environment.   Three months old good quality vegetatively-propagated seedlings were transplanted under two light intensities (under transparent canopy and shading net). The result showed that  considering the factor of diameter classes and media in kayu ules stem cutting propagation, it had improved the survival of the stem cutting. Diameter class I was best grown in media type 3 with 46.67 ± 12.2 % of survival rate, diameter class II was best grown in media type 2 with 38.67 ± 11.6 % of survival rate, whereas diameter class III was best grown in media type 4 with 52 ± 6.9 % of survival rate. The transplanted seedlings also grew significantly better under transparent canopy with higher light intensity. The distinctive features of screw tree under shading net were wider leaf area, higher specific leaf area and relative water content but it was lower in above ground dry biomass compared to the kayu ules under transparent canopy.


2021 ◽  
Vol 8 (3) ◽  
pp. 1557-1666
Author(s):  
Guilherme Maia dos Santos ◽  
Ximena Mendes de Oliveira ◽  
Isabel Homczinski ◽  
Rafaella Carvalho Mayrinck ◽  
Willian Dos Santos Cavassim

Several forestry procedures affect tree volume and shape, such as spacing, pruning, and thinning. Studying and understanding the effect of these operations on stand attributes are very important for forest management. This study aimed to evaluate volume, form factor, and taper for Pinus taeda trees stratified into diameter classes within two planting spacings. In addition, we aimed to evaluate the time spent to scale each tree, measured with a chronometer. Indirect scaling was performed using a Criterion RD 1000. Thirty trees were scaled on each planting spacing (3 m x 2 m and 4 m x 2 m), totaling 60 trees encompassing all diameter classes. Tree volume was calculated using the Smalian equation. Tree volume, form factor, and taper were calculated to each tree and evaluated by stand (independent t-test) and diameter class (variance analysis and Tukey test).  The average scaling time was 4 minutes and 35 seconds, which decreased with practice (-24%). Form factor and taper differed with spacing and diameter class. Volume did not differ with spacing, but it did in the diameter classes. We concluded that indirect scaling is a practical method for tree volume assessment; higher planting density leads to more cylindrical stems with lower taper ratios in comparison with denser stands; and the fact that tree volume, form factor and taper differed among the diameter classes should be incorporated into studies of taper modeling.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 922
Author(s):  
Zhen Zhang ◽  
Guoqing Jin ◽  
Tan Chen ◽  
Zhichun Zhou

Cypress (Cupressus funebris Endl.) is a major tree species planted for forestland restoration in low-fertility soil and in areas where rocky desertification has occurred. Calcium (Ca) fertilizer can adjust the pH of soil and has an important effect on the growth of cypress. Soil and water losses are serious in Southern China, and soil acidification is increasing, which results in high calcium loss. However, the adaptability of cypress clones to different concentrations of calcium in acidic soils has not been studied. In this investigation, a potted-plant experiment was set up with three concentrations of calcium oxide (CaO) fertilizer (0, 3, and 6 g·kg−1) added under local soil conditions with 0 and 3 g·kg−1 nitrogen (N), phosphorus (P), and potassium (K) fertilizer. The effects of CaO on the growth, root development, and nutrient uptake and utilization efficiency of cypress clones were analyzed. The growth, root development, and nutrient absorption and utilization of cypress differed when calcium fertilizer was applied to acidic soils with different degrees of fertility. In the soil with 0 g·kg−1 NPK fertilizer, the 3 and 6 g·kg−1 CaO treatments significantly increased the clonal growth of cypress seedling height, basal diameter, and dry-matter weight. In addition, the length, surface area, and volume of the roots less than 2.0 mm of root diameter also significantly increased, indicating that the fine cypress roots were somewhat able to adapt to differing Ca levels under lower fertility conditions. Moreover, the efficiency of N, P, and Ca accumulation was highest in the 3 g·kg−1 CaO treatment. After adding 3 g·kg−1 CaO fertilizer to the soil with 3 g·kg−1 NPK fertilizer, only the root dry-matter weight increased significantly, indicating that root development (including root length, surface area, and volume) in the D1–D3 diameter classes (≤1.5 mm in diameter) was significantly elevated. When CaO application reached 6 g·kg−1, the seedling height, basal diameter, and dry-matter weight of each organ decreased, as did the length, surface area, and volume of the roots in the all diameter classes, indicating that the addition of excessive CaO to fertile soil could inhibit the growth and root development of cypress. In Ca-deficient low-quality acidic soils, adding CaO fertilizer can promote the development of fine roots and the uptake and utilization of N, P, and Ca. The results of this study provide a basis for determining the optimal fertilization strategy when growing cypress in acidic soils in Southern China.


2021 ◽  
Vol 64 (1) ◽  
pp. 99-110
Author(s):  
Neşe Gülci ◽  
Kıvanç Yüksel ◽  
Sercan Gülci ◽  
Hasan Serin ◽  
Ebru Bilici ◽  
...  

In fully mechanized forest harvesting systems, tree felling activities are mostly performed by using harvesters or feller-bunchers. In some regions of Turkey, where terrain conditions and stand characteristics are suitable, fully mechanized harvesting systems have been recently practiced by some of the logging contractors as private forest industry demands for large amounts of forest products throughout the year. Thus, performances of these newly practiced harvesting systems should be carefully analyzed in order to implement productive and cost-effective mechanized harvesting systems. In this study, productivity of whole-tree harvesting using a feller-buncher was investigated based on stand parameters including tree height, DBH, and volume. The DBH of the felled trees were divided into four classes (i.e. very small: 16-19 cm, small: 20-23 cm, medium: 24-27 cm and large: 28-31 cm) to investigate the effects of various DBH class on the time consumption of cutting stage and productivity of the feller-buncher. To estimate productivity of feller-buncher in harvesting operation, multiple linear and polynomial regressions were also developed and discussed after the interpretation of diagnostic plots. The results indicated that the average productivity of the feller-buncher was 74.96 m3 /h which was closely related with tree height (r = 0.63), DBH (r = 0.67), and volume (r = 0.67). The average moving time was the most time-consuming stage (60%), followed by cutting (29%) and bunching stages (11%). It was found that DBH classes caused statistically significant (p < 0.05) effects on the time spent on cutting stage and productivity of the feller-buncher. The cutting time and productivity increased from very small to large diameter classes, while bunching time increased from very small to small diameter and then medium diameter to large diameter classes. Polynomial regression had a positive impact on the performance of the estimation model of manually field-measured data based on the error parameters.


2021 ◽  
Vol 67 (3) ◽  
pp. 181-186
Author(s):  
Victor Tkach ◽  
Igor Buksha ◽  
Oleksandr Slych ◽  
Volodymyr Pasternak

Abstract Oak (Quercus robur L.) forest stands are among the most common forest formations in the forest-steppe zone of Ukraine. Investigations of the patterns of distribution of trees by diameter and the dynamics of the commodity structure of mature oak stands of coppice origin were carried out based on the forest survey data from 28 temporary sample plots, on the sites designated for the final felling in the Left-Bank Forest Steppe of Ukraine (Sumy, Kharkiv, and Poltava Regions). We distributed trees by diameter classes and technical suitability categories. To establish the commodity structure of the stand, we selected model trees that corresponded to the average size of trees in terms of diameter classes and their qualitative characteristics. Then, we constructed a model tree stem profile using Institute of Forest Ecosystems Research (IFER)’s method of “6 points”. Based on stands’ structure and quality condition as well as on the growth tables, the commodity structure dynamics table for the changes in the commodity structure for the coppice oak stands in the Left-Bank Forest Steppe of Ukraine has been developed. The results of the analysis of wood stock dynamics showed that the maximum average increment of class A and B wood is 90–100 years. Therefore, the age of technical maturity and the associated age for the final felling in commercial oak forests of second site class and above should be assigned to 91–100 years.


2021 ◽  
Author(s):  
Elisa Arnone ◽  
Quintilio Napoleoni ◽  
Leonardo Noto

&lt;p&gt;&amp;#160;The effect of plant roots on hillslope stabilization against rainfall-induced shallow landslides depends on the mutual interaction between biotechnical characteristics of the root system (i.e., root length, root tensile strength, root area, root diameter profile) with the soil root-zone and the hydrological processes therein. Describing adequately the root architecture of a plant species is useful when root strength models, such as the Root Bundle Model (RBM), are applied to assess the ultimate root reinforcement.&lt;/p&gt;&lt;p&gt;This study describes the preliminary results of the calibration of an existing Root Topological Model (RTM) combined with a RBM model to estimate the additional roots shear resistance of vegetation typical of a subtropical climate.&lt;/p&gt;&lt;p&gt;Specifically, the dataset of the root system of four Hong Kong native species of shrubs (Rhodomyrtus tomentosa and Melastoma sanguineum) and trees (Schefflera heptaphylla and Reevesia thyrsoidea) has been used. The dataset includes the measurements relative to both the root architecture, i.e., root diameter classes and number of roots as function of depth, and the root resistance, i.e. root tensile strengths for each diameter classes, which were obtained from laboratory test.&lt;/p&gt;&lt;p&gt;The present application allows for calibrating and exploiting the potentiality of the framework RTM-RBM in a climatic environment different from the Mediterranean one analyzed so far for its development, thus testing the response and the flexibility of the modeling framework. The availability of such a tool could enhance, for example, the assessment of the most suitable plant species to be adopted for the slope stabilization in different soil and/or climatic conditions.&lt;/p&gt;


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Serdar Akburak ◽  
Ender Makineci

Abstract Background Thinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes. Method Two replicated control and thinning plots (50 m × 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0–2 mm (fine roots), 2–5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed. Results Except coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g∙m− 2) and thinned plots (1060 g∙m− 2) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period. Conclusion The results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics.


Sign in / Sign up

Export Citation Format

Share Document