scholarly journals Modelling the Effect of Weed Competition on Long-Term Volume Yield of Eucalyptus globulus Plantations Across an Environmental Gradient

2018 ◽  
Author(s):  
Felipe Vargas ◽  
Carlos A. Gonzalez-Benecke ◽  
Rafael Rubilar ◽  
Manuel Sanchez-Olate
Keyword(s):  
Eucalyptus Globulus ◽  
Growing Season ◽  
Annual Rainfall ◽  
Stem Volume ◽  
Long Term Effects ◽  
Vegetation Control ◽  
Competing Vegetation ◽  
Vegetation Biomass ◽  
Volume Yield

Several studies have quantified the responses of Eucalyptus globulus plantations to weed control on its early development (2-3 years after establishment). However, long-term results of competing vegetation effects have been rarely incorporated into growth and yield models that forecast the long-term effects of reducing the intensity of competing vegetation control and its interaction with site resource availability on stem volume production close to rotation age. We compared several models predicting stand stem volume yield of Eucalyptus globulus plantations established across a water and fertility gradient growing under different intensity levels of free area of competing vegetation maintained during the first 3 years of stand development. Four sites were selected encompassing a gradient in rainfall and amount of competing vegetation. Treatments were applied at stand establishment and were monitored periodically until age 9 years. Competing vegetation control intensity levels considered 0, 5, 20, 44 and 100% weed-free cover around individual E. globulus seedlings. Maximum competing vegetation biomass production during the first growing season were 2.9, 6.5, 2.2 and 12.9 Mg ha-1, for sites ranging from low to high annual rainfall. As expected, reductions in volume yield at age 9 years were observed as competing vegetation control intensity decreased during the first growing season. A strong relationship was established between stem volume yield loss and the intensity of competing vegetation control, the amount of competing vegetation biomass produced during the first growing season and mean annual rainfall. The slope of the relationship was different among sites and was related mainly to water and light limitations. Our results, suggest that the biomass of competing vegetation (intensity of competition) affecting site resource availability, contribute to observed long-term effects on E. globulus plantations productivity. The site with the lowest mean annual rainfall showed the highest volume yield loss at age 9 years. Sites with highest rainfall showed contrasting results related to the amount of competing vegetation biomass.

scholarly journals Modelling the Effect of Weed Competition on Long-Term Volume Yield of Eucalyptus globulus Labill. Plantations across an Environmental Gradient

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 480
Author(s):  
Felipe Vargas ◽  
Carlos Gonzalez-Benecke ◽  
Rafael Rubilar ◽  
Manuel Sanchez-Olate
Keyword(s):  
Eucalyptus Globulus ◽  
Environmental Gradient ◽  
Yield Loss ◽  
Growing Season ◽  
Annual Rainfall ◽  
Vegetation Control ◽  
Competing Vegetation ◽  
Vegetation Biomass ◽  
Volume Yield

Several studies have quantified the responses of Eucalyptus globulus Labill. plantations to weed control on its early development (2–3 years after establishment). However, long-term results of competing vegetation effects have not been included into growth and yield models that incorporate treatments of competing vegetation control, and its interaction with site resource availability. In this article, we compared several models predicting stand volume yield of E. globulus plantations established across an environmental gradient, growing under different intensity levels of competing vegetation control. Four sites were selected encompassing a gradient in rainfall and amount of competing vegetation. Treatments were applied at stand establishment and were monitored periodically until age 9 years. Competing vegetation control intensity levels considered 0, 5, 20, 44, and 100% weed-free cover around individual E. globulus cuttings. Maximum competing vegetation biomass production during the first growing season were 2.9, 6.5, 2.2, and 12.9 Mg ha−1, for sites ranging from low to high annual rainfall. As expected, reductions in volume yield at age 9 years were observed as competing vegetation control intensity decreased during the first growing season. A strong relationship was established between stem volume yield loss and the intensity of competing vegetation control, the amount of competing vegetation biomass produced during the first growing season and mean annual rainfall. The slope of the relationship was different among sites and was related mainly to water and light limitations. Our results suggest that the biomass of competing vegetation (intensity of competition), affecting site resource availability, contribute to observed long-term effects on E. globulus plantations productivity. The site with the lowest mean annual rainfall showed the highest volume yield loss at age 9 years. Sites with highest rainfall showed contrasting results related to the amount of competing vegetation biomass.

scholarly journals Long-term effects of silviculture on soil carbon storage: does vegetation control make a difference?

2012 ◽  
Vol 86 (1) ◽  
pp. 47-58 ◽  
Author(s):  
R. F. Powers ◽  
M. D. Busse ◽  
K. J. McFarlane ◽  
J. Zhang ◽  
D. H. Young
Keyword(s):  
Soil Carbon ◽  
Carbon Storage ◽  
Soil Carbon Storage ◽  
Long Term Effects ◽  
Vegetation Control

scholarly journals The effects of carbon emissions, rainfall, temperature, inflation, population, and unemployment on economic growth in Saudi Arabia: An ARDL investigation

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248743
Author(s):  
Md Mazharul Islam ◽  
Majed Alharthi ◽  
Md Wahid Murad
Keyword(s):  
Economic Growth ◽  
Time Series ◽  
Saudi Arabia ◽  
Carbon Emissions ◽  
Annual Rainfall ◽  
Long Term Effects ◽  
Ardl Model ◽  
Long Run ◽  
Unemployment Problem

Objective While macroeconomic and environmental events affect the overall economic performance of nations, there has not been much research on the effects of important macroeconomic and environmental variables and how these can influence progress. Saudi Arabia’s economy relies heavily on its vast reserves of petroleum, natural gas, iron ore, gold, and copper, but its economic growth trajectory has been uneven since the 1990s. This study examines the effects of carbon emissions, rainfall, temperature, inflation, population, and unemployment on economic growth in Saudi Arabia. Methods Annual time series dataset covering the period 1990–2019 has been extracted from the World Bank and General Authority of Meteorology and Environmental Protection, Saudi Arabia. The Autoregressive Distributed Lag (ARDL) approach to cointegration has served to investigate the long-run relationships among the variables. Several time-series diagnostic tests have been conducted on the long-term ARDL model to check its robustness. Results Saudi Arabia can still achieve higher economic growth without effectively addressing its unemployment problem as both the variables are found to be highly significantly but positively cointegrated in the long-run ARDL model. While the variable of carbon emissions demonstrated a negative effect on the nation’s economic growth, the variables of rainfall and temperate were to some extent cointegrated into the nation’s economic growth in negative and positive ways, respectively. Like most other nations the short-run effects of inflation and population on economic growth do vary, but their long-term effects on the same are found to be positive. Conclusions Saudi Arabia can achieve both higher economic growth and lower carbon emissions simultaneously even without effectively addressing the unemployment problem. The nation should utilize modern scientific technologies to annual rainfall losses and to reduce annual temperature in some parts of the country in order to achieve higher economic growth.

Use of false rings in Austrian pine to reconstruct early growing season precipitation

2000 ◽  
Vol 30 (11) ◽  
pp. 1691-1697 ◽  
Author(s):  
Rupert Wimmer ◽  
Giorgio Strumia ◽  
Franz Holawe
Keyword(s):  
Growing Season ◽  
Pinus Nigra ◽  
Annual Rainfall ◽  
Dummy Variable ◽  
False Rings ◽  
Growing Seasons ◽  
Dry Conditions ◽  
Earlywood Width ◽  
Linear Regressions

As a consequence of dry conditions, coniferous trees may produce radially smaller diameter tracheids within their tree rings before regular latewood formation starts. The resulting structures, which are commonly called false rings, have demonstrated utility as an environmental indicator. However, the climatic patterns behind false rings and their potential use in climate reconstruction models have been barely explored. The study is based on 313 Austrian pines (Pinus nigra Arn.) sampled at 29 sites in the Viennese basin, an area with low annual rainfall, extended dry periods during the growing season and usually severely cold winters. False rings relate significantly to May precipitation, and in years with higher false-ring proportions, a relationships with the combination of wet April, dry May, and wet June is often seen. In linear regressions, the presence-absence of false rings was used as a "dummy" variable and, together with earlywood width, explained 31% of variation in May precipitation. Years with high false-ring proportions were found when May precipitation was less than half its long-term average. False-ring trends during the past 100 years were closely associated with changing May rainfall pattern. Overall, false rings are shown to be a useful tree-ring feature and may be applied successfully in dendroclimatic studies, i.e., in the reconstruction of very low rainfall months in early growing seasons during pre-instrumental periods.

scholarly journals Long-term effects of CO2 enrichment on bud phenology and shoot growth patterns of Norway spruce juvenile trees

2010 ◽  
Vol 56 (No. 6) ◽  
pp. 251-259 ◽  
Author(s):  
R. Pokorný ◽  
I. Tomášková ◽  
I. Drápelová ◽  
J. Kulhavý ◽  
V. Marek M
Keyword(s):  
Norway Spruce ◽  
Shoot Growth ◽  
Carbon Sink ◽  
Growing Season ◽  
Shoot Elongation ◽  
Growth Patterns ◽  
Elongation Growth ◽  
Long Term Effects ◽  
Bud Phenology

Bud phenology and shoot elongation growth were monitored on Norway spruce (Picea abies [L.] Karst.) trees grown inside glass domes with adjustable windows for six years under ambient (355 &micro;mol CO<sub>2</sub>∙mol<sup>&ndash;1</sup>) and elevated (700 &micro;mol CO<sub>2</sub>∙mol<sup>&ndash;1</sup>) atmospheric CO<sub>2</sub> concentrations CO<sub>2</sub>. Each treatment consisted of two stand densities &ndash; sparse (5,000 trees∙ha<sup>&ndash;1</sup>) and dense (10,000 trees∙ha<sup>&ndash;1</sup>). The age of spruce trees was 10 years at the beginning of the experiment.Elevated CO<sub>2</sub> slightly accelerated the consequential bud germinating phases and it significantly induced shoot elongation growth, especially of sun-exposed shoots in a stand with sparse density. This accelerated growth lasted one to three weeks after full bud development in E compared to A. At the end of the growing season the total shoot length did not show any differences between the treatments. We supposed that limiting nitrogen supply to needles slowed down subsequent shoot elongation growth in E treatment. Nevertheless, faster shoot growth in elevated CO<sub>2</sub> conditions can enhance the carbon sink in spruce due to prolongation of the growing season.

scholarly journals Long-term trends of climate change and its impact on crop growing season on Montreal Island

2016 ◽  
Vol 8 (1) ◽  
pp. 78-88
Author(s):  
Erika Bouchard ◽  
Zhiming Qi
Keyword(s):  
Climate Change ◽  
Daily Rainfall ◽  
Growing Season ◽  
Annual Rainfall ◽  
Climate Trends ◽  
Growing Season Length ◽  
Mk Test ◽  
Long Term Trends ◽  
Increasing Trends

Long-term trends in air temperature and precipitation under climate change were analyzed for two meteorological stations on the Island of Montreal: McGill (1872–1986) and Pierre-Elliott-Trudeau (P-E-T, formerly Dorval) Airport (1942–2014). A linear trendline analysis, the Mann–Kendall (MK) test and the two-sample Kolmogorov–Smirnov (KS) test were conducted to assess specific climate trends. On a 100-year basis, temperature increased 1.88°C (34%) and 1.18°C (19%) at the McGill and P-E-T Airport sites, respectively, while annual rainfall increased 23.9 mm y−1 (2.3%) and 138.8 mm y−1 (15%) over the same period. The frequency of 50% (every other year) and 95% (every year) annual maximum daily rainfall events showed decreasing trends for the McGill station, but increasing trends for the P-E-T Airport station. Growing degree-days and growing season length are prone to being influenced by climate change and are critical to managing agricultural activities in the Montreal region; both showed increasing trends. At the same time, the onset of the growing season occurred earlier as time progressed.

scholarly journals Long term effects of withholding phosphate application on North Island hill country: Ballantrae

1990 ◽  
pp. 25-28 ◽  
Author(s):  
M.G. Lambert ◽  
D.A. Clark ◽  
A.D. Mackay
Keyword(s):  
Residual Activity ◽  
Annual Rainfall ◽  
Research Station ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Phosphate Retention ◽  
Reactive Phosphate Rock ◽  
Average Annual Rainfall

In a farmlet grazing trial at DSIR's Ballantrae Hill Country Research Station near Woodville the effect of withholding phosphate application was investigated. Soils are yellow-brown earths and related steepland soils with low phosphate retention, and average annual rainfall is 1200 mm. Four 10 ha farmlets, 2 each with histories of high (HF) or low (LF) superphosphate application, had annual applications continued at 125 (LF-LF) or 375 (HFHF) kg/ha; or discontinued on one farmlet in each case (LF-NF and HF-NF), starting in 1981. Soil Olsen P level decreased on the HF-NF area, but not on LF-NF and pasture production decreased by 4.6 and 1.7% p.a. respectively. Botanical composition was affected only on the HF-NF farmlet. Ewes were lighter as a result of not applying fertiliser. Ewe and lamb wool production, and lamb liveweight, were reduced by an average 1.2, 3.7 and 2.6% p.a., respectively, over the 7 years. A phosphate application trial suggested that reactive phosphate rock was as effective as superphosphate in stimulating legume responses in the 1st year after restarting phosphate application, and had greater residual activity. Keywords fertiliser, withholding, cessation, phosphate, superphosphate, hill country, pastures, soil fertility, wool, sheep

scholarly journals Farmer Adaptation to Climate Variability and Soil Erosion in Samanalawewa Catchment in Sri Lanka

2021 ◽  
pp. 291-307
Author(s):  
E. P. N. Udayakumara
Keyword(s):  
Sri Lanka ◽  
Soil Erosion ◽  
Climate Variability ◽  
Water Conservation ◽  
Annual Rainfall ◽  
Long Term Effects ◽  
Average Annual Temperature ◽  
Soil Erosion Assessment ◽  
Soil And Water

AbstractThe Samanalawewa catchment is considered one of the most important catchments in Sri Lanka because of its diverse land uses. Hence, this study examines the long-term effects on climate variability, soil erosion soil erosion, and adoption of soil and water conservation (SWC) measures in the Samanalawewa reservoir. Rainfall and temperature data indicated that annual rainfall decreased from 1922 to 2008 by an average of 5.5 mm per year while the average annual temperature increased from 1973 to 2008 at a rate of 0.02 °C per year. Moreover, model-based soil erosion assessment disclosed that the rate of soil erosion ranges from 0 to 289 t per ha per year with an average of 4.3 t per ha per year.

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