site index
Recently Published Documents


TOTAL DOCUMENTS

741
(FIVE YEARS 104)

H-INDEX

36
(FIVE YEARS 4)

Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 36
Author(s):  
Jason G. Vogel ◽  
Rosvel Bracho ◽  
Madison Akers ◽  
Ralph Amateis ◽  
Allan Bacon ◽  
...  

Tree plantations represent an important component of the global carbon (C) cycle and are expected to increase in prevalence during the 21st century. We examined how silvicultural approaches that optimize economic returns in loblolly pine (Pinus taeda L.) plantations affected the accumulation of C in pools of vegetation, detritus, and mineral soil up to 100 cm across the loblolly pine’s natural range in the southeastern United States. Comparisons of silvicultural treatments included competing vegetation or ‘weed’ control, fertilization, thinning, and varying intensities of silvicultural treatment for 106 experimental plantations and 322 plots. The average age of the sampled plantations was 17 years, and the C stored in vegetation (pine and understory) averaged 82.1 ± 3.0 (±std. error) Mg C ha−1, and 14.3 ± 0.6 Mg C ha−1 in detrital pools (soil organic layers, coarse-woody debris, and soil detritus). Mineral soil C (0–100 cm) averaged 79.8 ± 4.6 Mg C ha−1 across sites. For management effects, thinning reduced vegetation by 35.5 ± 1.2 Mg C ha−1 for all treatment combinations. Weed control and fertilization increased vegetation between 2.3 and 5.7 Mg C ha−1 across treatment combinations, with high intensity silvicultural applications producing greater vegetation C than low intensity (increase of 21.4 ± 1.7 Mg C ha−1). Detrital C pools were negatively affected by thinning where either fertilization or weed control were also applied, and were increased with management intensity. Mineral soil C did not respond to any silvicultural treatments. From these data, we constructed regression models that summarized the C accumulation in detritus and detritus + vegetation in response to independent variables commonly monitored by plantation managers (site index (SI), trees per hectare (TPH) and plantation age (AGE)). The C stored in detritus and vegetation increased on average with AGE and both models included SI and TPH. The detritus model explained less variance (adj. R2 = 0.29) than the detritus + vegetation model (adj. R2 = 0.87). A general recommendation for managers looking to maximize C storage would be to maintain a high TPH and increase SI, with SI manipulation having a greater relative effect. From the model, we predict that a plantation managed to achieve the average upper third SI (26.8) within our observations, and planted at 1500 TPH, could accumulate ~85 Mg C ha−1 by 12 years of age in detritus and vegetation, an amount greater than the region’s average mineral soil C pool. Notably, SI can be increased using both genetic and silviculture technologies.


2021 ◽  
Author(s):  
Mathilde Pau ◽  
Sylvie Gauthier ◽  
Raphaël D. Chavardès ◽  
Martin P. Girardin ◽  
William Marchand ◽  
...  

2021 ◽  
Vol 32 (6) ◽  
pp. 1171-1182
Author(s):  
Seok Won Choi ◽  
Hee Jung Park ◽  
Byung Jun Ko ◽  
Se Ik Park ◽  
Sang Hyun Lee

2021 ◽  
Vol 67 (No. 11) ◽  
pp. 533-543
Author(s):  
Viktoriia Lovynska ◽  
Andriy Terentiev ◽  
Petro Lakyda ◽  
Svitlana Sytnyk ◽  
Olexander Bala ◽  
...  

The goal of the study was to compare the dynamic changes in individual biometric indices of Scots pine in different natural zones of Ukraine, Polissya and Steppe. Scots pine stands were mainly concentrated in the Polissya zone, and their area was 3.6 times larger than that of forests in the Steppe zone, and the total wood stock by 4.6 times. The regression equations for biometric indices of artificial modal stands were developed. A comparison of the average height, diameter, and wood stock for pine stands of site index І<sup>а</sup>, I, and II growing in Polissya and Steppe was made. It was found that the average differences in the average height (from 1.9 to 2.6 m) are observed at the age of 15–20 years. For the average diameter, the difference increases with age and the growth of the site index. The difference in the average stock is constantly increasing with age. At the age of 20 years this difference is 20–30 m<sup>3</sup>, and at the age of 120 years from 100 to 120 m<sup>3</sup> depending on the site index. The developed growth models can be used in planning and prioritizing appropriate forestry activities for pine stands growing in specific regional conditions.


2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Mehmet Demirci ◽  
Ahmet Yesil ◽  
Pete Bettinger

Long-term management plans have been developed for nearly all of the forests in Turkey. These plans are applied at a sub-district management unit level and may contain guidance for both intermediate yield and final yield harvests. To implement an intermediate yield plan, which involves the scheduling of forest thinnings (stand tending), consideration in Turkey is given to the advantages of working in the same terrain and the same general area each year. Therefore, compartments are often clumped together to create thinning blocks, taking into consideration the thinning priority of the stands, road conditions, site index, age, and proximity of the compartments. Further, when preparing annual budgets and planning to meet the market’s needs, forest enterprises require an even flow of intermediate wood volume each year. In this paper, we introduce a new approach in stand tending planning designed to schedule an equal amount of intermediate wood volume each year and to create thinning blocks by minimizing the distance to pre-defined ramps (landings). We developed both linear and nonlinear goal programming models to minimize both the deviations from a harvest volume (annual intermediate yield allowable cut) target and the deviations from a target value determined for the distances (total and average) of the centroid of each compartment to the hypothetical forest ramps. By using the extended version of Lingo 16, we solved the problem with different weights for the deviations in volume and distance that ranged from 0.0 to 1.0, in 10% intervals, which created 11 scenarios. We carefully analyzed the results of each scenario by taking into consideration the wood volume and distance of compartments to the ramps. The best scenario using the linear model produced a deviation in volume scheduled for the entire decade of 6 m3, while the deviation in total distance between harvest areas and ramps was 59.7 km. Scenario 5, with weights of 0.6 for volume and 0.4 for distance, produced these results, where compartments were closest to one another. The best scenario using the nonlinear model also produced a deviation in volume of 0 m3 and the total average deviation in distance between harvest areas and ramps was 8.7 km. Scenario 3, with weights of 0.8 for volume and 0.2 for distance, produced these results. The approach and models described through this study may be appropriate for further integration into forest management planning processes developed for the planning of Mediterranean forests.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nattawan Suwannakul ◽  
Kaoru Midorikawa ◽  
Chunping Du ◽  
Ya-Peng Qi ◽  
Jie Zhang ◽  
...  

AbstractCholangiocarcinoma (CCA) is a malignant disease with a poor prognosis, and several studies have been conducted using different molecular markers as a tool for CCA diagnosis, including Clonorchis sinensis (CS)-CCA. We initially identified the expression profiles of the three markers of interest, HMGB1, SOX9, and YAP1, using GSE (GSE76297 and GSE32958) datasets. Upregulated levels of these three proteins were detected in CCA samples compared to those in normal samples. To clarify this issue, 24 human CCA tissues with paired adjacent normal tissues were evaluated using immunohistochemical staining. Of the three markers, the total cellular staining intensities were scanned, and subcellular localization was scored in the nuclear and cytoplasmic regions. The intensities of HMGB1, SOX9, and YAP1 were elevated in CCA tissues than the adjacent normal tissues. Individual scoring of subcellular localization revealed that the expression levels of HMGB1 (nucleus) and YAP1 (nucleus and cytoplasm) were significantly different from the pathologic M stage. Moreover, the translocation pattern was categorized using “site-index”, and the results demonstrated that the overexpression of HMGB1 and SOX9 was mostly observed in both the nucleus and cytoplasm, whereas YAP1 was predominantly expressed in the cytoplasm of tumor cells. Interestingly, the site index of HMGB1 was moderately correlated with the tumor stage (r = 0.441, p = 0.031). These findings imply that the overexpression of subcellular HMGB1 could be associated with the metastatic status of patients with CS-CCA, which was shown to be effective for CS-CCA prognosis.


FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 980
Author(s):  
Mário Dobner Jr.

Plantation forestry in southern Brazil demands additional timber species to a higher market differentiation by providing high quality timber and exploitation of market niches. Cupressus lusitanica has long been recognized for this purpose but, until now, it was not properly region-wide quantified in terms of growth and yield. The present study delivers the lacking quantitative approach, which may encourage the commercial use of the species. With this study it was aimed at collecting and processing quantitative data from all known C. lusitanica stands in southern Brazil. Inventories were carried out (60 ha, 6-39 years of age) in order to model the development of dominant height (h100), basal area, volume and dominant diameter (d100). Dominant height was the basis for site quality evaluation, delivering site index curves, which, together with the commercial volume of the stands, allowed yield modelling. A wide amplitude of dominant height growth was detected (10-30 m at 20 years), indicating a great site quality variation. At age of 20 years, commercial volumes of 110 and 620 m³ ha-1 were observed for site indexes of 14 and 26, respectively, equivalent to a maximum of 6-31 m³ ha-1 year-1 at ages between 16-18 years. Results demonstrated in a robust manner that C. lusitanica has a high potential for cultivation in southern Brazil. Thus, offering the opportunity of market differentiation by promoting market niches whose demands timber for special solid end-uses.


FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 1000
Author(s):  
Pedro Vaz da Rocha ◽  
Emanuel José Gomes de Araújo ◽  
Vinícius Augusto Morais ◽  
Marco Antonio Monte ◽  
Danilo Henrique dos Santos Ataíde ◽  
...  

The objective of this work was to evaluate the efficiency of models and methods to obtain the site index, associated with ordinary kriging, to classify productive capacity in eucalyptus stands. Thus, the site quality was performed considering the traditional modeling in clonal stands (2,119 hectares) located in Minas Gerais state, Brazil. 170 plots of 400m2 were randomly allocated, representing a sampling intensity of 0.32%. The dominant height of trees (Assmann) was measured at 24, 36, 48, 60, 72, and 84 months. The site index (S) was estimated by the guide curve and algebraic difference methods, using the models of Schumacher, Chapman and Richards, and Bailey and Clutter. 136 plots were used in the fit and 34 plots in the predictive validation. The spatial dependence of site index was evaluated by experimental semivariogram and adjustment of exponential, spherical, and gaussian models. After confirming the spatial dependence, ordinary kriging was performed to spatialize the site index. For the predictive validation, the dominant height values at 72 months were used. The algebraic difference method provided excellent estimates of site index, which showed spatial dependence in all adjustments, from moderate to strong. In most cases, the gaussian model was the most accurate. It is concluded that the algebraic difference method was more efficient and the site index showed strong spatial dependence at all ages, regardless of the model used. Thus, regression models for site index estimation can be used in combination with ordinary kriging techniques.


2021 ◽  
Vol 63 (3) ◽  
pp. 243-259
Author(s):  
Piotr T. Zaniewski ◽  
Ciurzycki Wojciech ◽  
Zaniewska Ewa

Abstract The range of acidophilous oak forest from Quercetea robori-petraeae Br-Bl. et Tx. ex Oberd. 1957 in Central Europe depends largely on the syntaxonomical concept used and is still provisional. The most continental association from this class occurring in Poland is Calamagrostio arundinaceae-Quercetum petraeae Hartm. 1934 Scam. et Pass. 1959. It is present in western and central Poland, but its eastern boundary is not well known. The aims of the study were to survey and document new patches of Calamagrostio-Quercetum in central Poland, to check the internal variation of the association and to summary the known distribution of it in lowlands of central-western and central Poland. 23 phytosociological relevés were made within new stands together with soil sampling. New relevé data was subjected to the numerical Wards classification together with acidophilous oak forests datasets from western Poland and oak-pine forests ones from eastern part of the Country. The new dataset was similar to Calamagrostio-Quercetum. Three subassociations were distinguished. Soil parameters and oak site index did not differ from acidophilous oak forest stands from other parts of Poland. The provisional range of Calamagrostio-Quercetum in central Poland was proposed to be moved by circa 60–90 km to the north-east (approximately as far as the Vistula river line) in order to include south-western part of Mazowsze.


Sign in / Sign up

Export Citation Format

Share Document