The effect of spacing on the growth ofEucalyptus camaldulensison salt-affected soils of the Punjab, Pakistan

2008 ◽  
Vol 38 (9) ◽  
pp. 2434-2444 ◽  
Author(s):  
Javaid Akhtar ◽  
Z. A. Saqib ◽  
R. H. Qureshi ◽  
M. A. Haq ◽  
M. S. Iqbal ◽  
...  

This study compared the performance of Eucalyptus camaldulensis Dehnh. planted at four spacings (2.0 m × 2.0 m, 2.5 m × 2.5 m, 3.0 m × 3.0 m, and 3.5 m × 3.5 m) at three experimental saline sites in Punjab province of Pakistan over 5 years and assessed the impact of these planting densities on soil salinity amelioration. Tree response was assessed by measuring survival, height, and diameter at breast height (DBH) of trees at 1, 2, and 5 years as well as wood volume after 5 years. Wood volume per hectare, height, and DBH were greater at sites I and II than at site III. The 3.0 m × 3.0 m spacing resulted in taller trees, but DBH and wood volume were greater with the 3.5 m × 3.5 m spacing. The study confirmed that initial tree spacing or density has a significant impact on the subsequent height, DBH, and wood volume of E. camaldulensis plants. The study also showed that broad spacing could be a better option in saline environments. There was a definite reduction in soil salinity (electrical conductivity, ECe) at five soil depths after 5 years of tree growth at all sites and spacing treatments, with reductions varying from 46% to 47% at site I, 31% to 52% at site II, and 25% to 58% at site III. Soil ECewas generally higher in surface (0–15 cm) soils.

2020 ◽  
Vol 69 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ikumi Nezu ◽  
Futoshi Ishiguri ◽  
Haruna Aiso ◽  
Sapit Diloksumpun ◽  
Jyunichi Ohshima ◽  
...  

AbstractTo promote solid wood production, the diameter at breast height, height, stress-wave velocity, surface-released strain, basic density and compressive strength parallel to the grain were measured for 10 half-sib families of 12-year-old Eucalyptus camaldulensis Dehnh. trees growing in Thailand. Based on the results, growth rates, correlations among measured properties, radial and among-family variations of wood properties, and their repeatability were evaluated. Diameter at breast height, height, and wood volume were exponentially increased at initial stage, and then gradually increased toward to 12 years after planting. The maximum current annual increment and mean annual increment in wood volume showed at age of 8 and 11years old, suggesting that rotation period for optimum productivity may be ranged from 8 to 11 years old. Wood with stable properties was found greater than 6 cm from the pith. These results indicate that 12-year-old E. camaldulensis trees had already reached the maturation stage. No significant correlations were found between growth characteristics and wood properties. Significant variances in the height, stress-wave velocity, and basic density were found among the 10 families. The F-values and repeatability of the wood properties in the outer wood were higher than those in the inner wood. These results indicate that the properties of the outer wood are closely related to genetic factors. Thus, to obtain superior E. camaldulensis trees for solid wood production, the family selection should be conducted using the outer wood of aged trees.


1996 ◽  
Vol 23 (4) ◽  
pp. 509 ◽  
Author(s):  
RCC Farrell ◽  
DT Bell ◽  
K Akilan ◽  
JK Marshall

Eucalyptus camaldulensis Dehnh. has previously been shown to survive and grow in waterlogged, highly saline and highly alkaline soils. The ability of six clones from five provenances of E. camaldulensis to produce biomass and utilise water, and the processes of stomatal conductance and gas exchange under stress conditions was examined under controlled conditions in a glasshouse. A clone originally from Wooramel, Western Australia (M80) produced the largest total plant biomass, the greatest total leaf area and greatest total root dry weight under conditions of waterlogging and gradually increasing salinity. A second clone from Wooramel (M16), however, tended to be among the least productive of the clones under this stress, indicating the wide potential variation in stress tolerance of trees from a single provenance. The response of clones to alkalinity stress was comparable to that measured under waterlogging/salinity stress. Water use was closely related to biomass production. Leaves produced while under salinity and alkalinity stress were comparable in ion content to those produced prior to the test conditions. An ability to control uptake by roots or limit ion transport to leaf tissues were hypothesised as controlling physiological functions resulting in tolerance to severe soil ion imbalances in this species. The impact of solution conductivity on stomatal conductance and water use, secondarily affected photosynthetic rates in these clones of E. camaldulensis. Tolerance of extreme conditions provides the opportunity to use these genotypes to reclaim damaged agricultural landscapes and mine spoils of high soil solution ion concentrations.


2012 ◽  
Vol 92 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Leonard A. Leskiw ◽  
Ron B. Sedor ◽  
Catherine M. Welsh ◽  
Takele B. Zeleke

Leskiw, L. A., Sedor, R. B., Welsh, C. M. and Zeleke, T. B. 2012. Soil and vegetation recovery after a well blowout and salt water release in northeastern British Columbia. Can. J. Soil Sci. 92: 179–190. The impact of brine release on soil and vegetation due to a gas well blowout in December 1999 near Fort Nelson, British Columbia was evaluated over a 10 year period. The objectives were to study spatial and temporal distribution of soil salinity and vegetation and determine whether reclamation would occur through a natural recovery process. Soil salinity and vegetation diversity indices were measured on six study sites and one control. Average electrical conductivity declined with time from approximately 3.0 dS m−1 and has remained below 2.0 dS m−1 since 2002. Cycling of ions between leaf litter and plant tissue resulted in high variability in topsoil electrical conductivity. Sodium adsorption ratio in the leaf litter and A horizons was low (<7), but remained high in B and C horizons (>14) after 2004. From 2002 to 2010 moss cover increased 40%, whereas shrubs decreased 30%. The most impacted plot showed higher diversity than the least impacted plots and the control (Shannon diversity index = 1.49, 1.36, 1.11 for most impacted, least impacted and control, respectively). Soil and vegetation indicated salt-affected plots were recovering naturally. Results from this study could potentially provide guidelines for future remediation and reclamation practices.


Author(s):  
Silva Raynara Ferreira da ◽  
Sousa Moema Barbosa de ◽  
Silva Aluísio Costa ◽  
Marinho Eduardo Silva ◽  
Dias Bruna Anair Souto

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.


2021 ◽  
Vol 285 ◽  
pp. 110171
Author(s):  
Sebastián Bañón ◽  
Sara Álvarez ◽  
Daniel Bañón ◽  
María Fernanda Ortuño ◽  
María Jesús Sánchez-Blanco

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