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 Effects of Season of Burning on the Microenvironment of Fescue Prairie in Central Saskatchewan

2003 ◽  
Vol 117 (2) ◽  
pp. 257 ◽  
Author(s):  
O. W. Archibold ◽  
E. A. Ripley ◽  
L. Delanoy
Keyword(s):  
Plant Cover ◽  
Growing Season ◽  
Control Plot ◽  
Area Index ◽  
Growing Seasons ◽  
Soil Temperatures ◽  
Second Year ◽  
Long Term Impact ◽  
Season Of Burning

The microenvironmental effects of spring, summer and autumn burns were investigated for a small area of fescue prairie in Saskatchewan over two growing seasons. Maximum fire temperature in all burns exceeded 300°C at a height of 5-10 cm in the canopy. At a depth of 1 cm in the soil, temperature increased to 40°C during the summer burn, but was unaffected by burns at other seasons. Spring-burned grasses recovered to the same height as the unburned control plot by the end of the first summer. Grass height was similar in all plots by the end of the second growing season, but aboveground biomass in all burned plots was about half that of the control. Graminoid leaf area index at the end of the second growing season ranged from 0.65 in the control plot to 0.27 in the autumn burn. Surface albedos dropped to about 0.03 immediately after burning and took about 3 months to return to the pre-burn values near 0.20. By mid-June of the second year, albedos were similar in all plots. Soil temperatures at 50 cm depth in the burned plots were higher than in the control during the first summer and lower during the winter. The greatest winter snowpack (73 mm water equivalent) accumulated in the control, compared to 48, 35 and 25 mm in the spring, summer and autumn burned plots, respectively. In the first growing season the greatest demand for water occurred in the spring plot followed by the summer, control and autumn plots. In the second season water demand did not differ significantly among plots, reflecting the similarities in plant cover. The microenvironmental effects of a single burning episode in fescue prairie disappear rather quickly, so that there is little long-term impact on the vegetation.

Temporal patterns of ground flora response to fire in thinned Pinus–Quercus stands

2018 ◽  
Vol 48 (10) ◽  
pp. 1171-1183 ◽  
Author(s):  
Kevin G. Willson ◽  
Carson R. Barefoot ◽  
Justin L. Hart ◽  
Callie Jo Schweitzer ◽  
Daniel C. Dey
Keyword(s):  
Prescribed Fire ◽  
Stand Structure ◽  
Growing Season ◽  
Forest Understory ◽  
Stand Management ◽  
Ground Flora ◽  
Growing Seasons ◽  
Understory Richness ◽  
Growing Conditions

The ground flora stratum affects stand structure, resource acquisition, nutrient cycling, and taxonomic richness in forest ecosystems. Disturbances such as thinning and prescribed fire alter forest understory growing conditions that generally increase ground flora cover and richness. We studied annual changes in ground flora assemblages over three growing seasons after fire in thinned and frequently burned (3-year rotation) Pinus–Quercus stands. Our results corroborated trends from other studies that indicated greater ground flora richness and cover after thinning and burning compared with thin-only treatments. We also found that the stratum experienced relatively rapid succession between growing seasons that complimented the tolerance succession model. Forbs had reduced cover and richness from increasingly difficult growing conditions over time and were replaced by woody plants, shrubs, and seedlings. This likely occurred from changing competition dynamics that favored quick growth in the first growing season and long-term investment in vertical growth in the third growing season. The successful regeneration pathways also fit ground flora regeneration models and added a unique pathway to strengthen the predictive power of these models. As many stand management goals are focused towards improving biodiversity, prescribed fire and thinning may be used to increase understory richness in Pinus–Quercus stands.

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 Ethylenediurea (EDU) effects on hybrid larch saplings exposed to ambient or elevated ozone over three growing seasons

2021 ◽  
Author(s):  
Evgenios Agathokleous ◽  
Mitsutoshi Kitao ◽  
Takayoshi Koike
Keyword(s):  
Photosynthetic Pigment ◽  
Ground Level ◽  
Growing Season ◽  
Growth Potential ◽  
Foliar Injury ◽  
Hybrid Larch ◽  
Ground Level Ozone ◽  
Growing Seasons ◽  
Elevated Ozone

AbstractGround-level ozone (O3) pollution is a persistent environmental issue that can lead to adverse effects on trees and wood production, thus indicating a need for forestry interventions to mediate O3 effects. We treated hybrid larch (Larix gmelinii var. japonica × L. kaempferi) saplings grown in nutrient-poor soils with 0 or 400 mg L−1 water solutions of the antiozonant ethylenediurea (EDU0, EDU400) and exposed them to ambient O3 (AOZ; 08:00 − 18:00 ≈ 30 nmol mol−1) or elevated O3 (EOZ; 08:00 − 18:00 ≈ 60 nmol mol−1) over three growing seasons. We found that EDU400 protected saplings against most effects of EOZ, which included extensive visible foliar injury, premature senescence, decreased photosynthetic pigment contents and altered balance between pigments, suppressed gas exchange and biomass production, and impaired leaf litter decay. While EOZ had limited effects on plant growth (suppressed stem diameter), it decreased the total number of buds per plant, an effect that was not observed in the first growing season. These results indicate that responses to EOZ might have implications to plant competitiveness, in the long term, as a result of decreased potential for vegetative growth. However, when buds were standardized per unit of branches biomass, EOZ significantly increased the number of buds per unit of biomass, suggesting a potentially increased investment to bud development, in an effort to enhance growth potential and competitiveness in the next growing season. EDU400 minimized most of these effects of EOZ, significantly enhancing plant health under O3-induced stress. The effect of EDU was attributed mainly to a biochemical mode of action. Therefore, hybrid larch, which is superior to its parents, can be significantly improved by EDU under long-term elevated O3 exposure, providing a perspective for enhancing afforestation practices.

Seasonal and long-term responses of host trees to microbial associates of the pine engraver, Ipspini

1988 ◽  
Vol 18 (12) ◽  
pp. 1624-1634 ◽  
Author(s):  
Kenneth F. Raffa ◽  
Eugene B. Smalley
Keyword(s):  
Seasonal Pattern ◽  
Growing Season ◽  
Lesion Formation ◽  
Pine Engraver ◽  
Growing Seasons ◽  
Host Trees ◽  
Significant Damage ◽  
Host Fungus ◽  
Lesion Growth

Within-season responses of Pinusresinosa and Pinusbanksiana to fungi vectored by the pine engraver, Ipspini, are strongly influenced by the month of inoculation. The seasonal pattern is a characteristic of the host-fungus interaction, rather than being indicative of either host-or fungal-specific properties alone. The most consistent trend was that early season inoculation resulted in more rapid lesion formation in sapwood than in phloem and that this difference declined as the growing season progressed. Prior inoculation had no effect on necrotic lesion formation. Inoculated trees were examined for three growing seasons. No significant damage related to treatment occurred to either P. resinosa or P. banksiana during this interval. However, Ceratocystisips persisted in living hosts for a longer period than did Ceratocystisnigrocarpa and showed signs of radial and vertical progression throughout the first and beginning of the second growing season. This was especially true in P. resinosa, the host in which the short-term studies revealed the lower lesion growth rate. There was no lesion formation during the third season. Inoculated fungi could be reisolated from within but not outside the resulting lesion.

Vernolate for Augmentation of Quackgrass (Agropyron repens) Control with Glyphosate

Weed Science ◽  
1980 ◽  
Vol 28 (6) ◽  
pp. 654-657 ◽  
Author(s):  
D. L. Wyse
Keyword(s):  
Zea Mays ◽  
Glycine Max ◽  
Field Experiment ◽  
Growing Season ◽  
Sequential Treatment ◽  
Growing Seasons ◽  
Combination Treatments ◽  
Agropyron Repens

A field experiment of 2 yr duration at two locations was conducted to determine the effectiveness of glyphosate [N-(phosphonomethyl)glycine] and vernolate (S-propyl dipropylthiocarbamate) as single or combination treatments for quackgrass [Agropyron repens(L.) Beauv.] control in a soybean [Glycine max(L.) Merr.]-corn [Zea mays(L.)] rotation. Vernolate applied preplant incorporated at 3.36 kg/ha gave 30 to 58% and 28 to 34% quackgrass control at the end of the first and second growing seasons, respectively. Spring applications of glyphosate at 1.12 and 1.68 kg/ha before plowing gave 53 to 90% quackgrass control at the end of the second growing season. Glyphosate at 1.12 and 1.68 kg/ha followed by vernolate preplant incorporated at 3.36 kg/ha gave 85 to 99% quackgrass control at the end of the second growing season. Although vernolate did not provide effective long term quackgrass control, it did effectively augment quackgrass control when applied as a sequential treatment to glyphosate applied at 0.56 or 1.12 kg/ha.

Competition between Wimmera ryegrass and narrow-leafed lupins

1985 ◽  
Vol 25 (4) ◽  
pp. 824 ◽  
Author(s):  
GW Arnold ◽  
J Weeldenberg ◽  
A Grassia
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Growing Season ◽  
Growth And Yield ◽  
Lower Percentage ◽  
Annual Rainfall ◽  
Growing Seasons ◽  
Wimmera Ryegrass ◽  
Lateral Branches ◽  
Very High

The ways in which Wimmera ryegrass (Lolium rigidum) affects the growth and yield of narrow-leafed lupins (Lupinus angustifolius) were studied in two experiments at Baker's Hill, W.A. (average annual rainfall 650 mm). In the first experiment, Uniharvest lupins and Wimmera ryegrass were grown alone and together starting at two dates. The three rates of ryegrass produced similar biomasses (total dry matter) at maturity (about 8000 kg/ha) but lupin grain yield decreased significantly with ryegrass sowing rate. One effect of ryegrass at the highest sowing rate was to alter the distribution of dry matter in the lupin canopy so that, at the end of the growing season, there was a lower percentage of leaf in the lower part of the canopy and this was associated with less light being received. Water stress in lupins at the end of the growing season was higher at the later planting with ryegrass. A multiple regression analysis showed that 74% of the variation in lupin grain yield between plots was due to variation in lupin height and biomass, and ryegrass tiller numbers in October. Lupins had little effect on ryegrass yield; although there were fewer tillers in the presence of lupins, weights of tillers were higher. In the second experiment, the effects of 38 ryegrass plants/m2 on growth of both Uniharvest and Unicrop lupins grown at a density of 40 plants/m2 were studied. Lupin biomass was unaffected until October but was then reduced significantly by the ryegrass, which yielded 4000 kg/ha dry matter. Grain yield was reduced because fewer pods were produced on lateral branches in both varieties, and on main stems in Uniharvest. The experiments showed that in good growing seasons, in high rainfall areas, lupins will yield grain even when grown with very high densities of ryegrass.

scholarly journals Weather, wheat, and war: Security implications of climate variability for conflict in Syria

2021 ◽  
Vol 58 (1) ◽  
pp. 114-131
Author(s):  
Andrew M Linke ◽  
Brett Ruether
Keyword(s):  
Civil War ◽  
Climate Variability ◽  
Growing Season ◽  
Precipitation Variability ◽  
Growing Seasons ◽  
Rebel Groups ◽  
Dry Conditions ◽  
The Government ◽  
Violent Events

We examine how Syria’s local growing seasons and precipitation variability affected patterns of violence during the country’s civil war (2011–19). Among Syria’s 272 subdistricts ( nahiyah), we study conflict events initiated by the Assad regime or its allies, and, separately, by other armed non-government groups (‘rebels’). Throughout the war, violence to capture agriculture has been used regularly to control valuable cropland and harvests. Combatants also seek to deny their adversaries access to these resources by deploying violence to destroy agriculture. We test the hypothesis that conflict was most likely during local growing seasons due to both of these motivations. Additionally, we examine whether unusually dry conditions further elevated the risk of conflict during growing season months. A theory for why higher levels of conflict would occur during unusually dry conditions is that livelihood losses elevate incentives to control scarce crops and also facilitate recruitment of militants or their sympathizers. We find that violent events initiated by the government and rebel groups are both more likely during the growing season than other times of the year. There is also evidence that dry conditions during the growing season led to an increase in government-initiated attacks over the duration of the war. We find the strongest relationship between precipitation deficits and both government- and rebel-initiated violence in later years of the war. Compared with our growing season results, the rainfall deviation estimates are less consistent across models.

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.

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