The Seasonal Growth of Eucalyptus regnans F. Muell

1975 ◽  
Vol 23 (2) ◽  
pp. 239 ◽  
Author(s):  
DH Ashton
Keyword(s):  
Growth Rates ◽  
Late Summer ◽  
Growing Season ◽  
Day Length ◽  
Maximum Diameter ◽  
Main Peak ◽  
Daily Maximum ◽  
Eucalyptus Regnans ◽  
Air Temperatures ◽  
The Mean

At Wallaby Creek, Vic. (altitude 670 m), Eucalyptus regnans seedlings 1-6 m in height usually commence growth in early September, reach maximum growth in midsummer and cease growing in late May. The active growing season when shoot growth exceeds 12 mm per month is 7-9½. months. Slow growth occurs in midwinter in Melbourne (altitude 47 m) and is not affected by day length. The growth rates of seedlings of associated understorey species are, in descending order of magnitude: Acacia dealbata, E. vegnans, Prostantheva lasianthos, Pomadevvis aspeva, Acacia melanoxylon. Their growth periods are similar, except for that of A. melanoxylon which is much shorter. Leaves of E. regnans mature in 2½-3½ months. In larger seedlings some of the leaves produced are initiated during the growing season. The size of the mature leaf depends partly on the season of its emergence. In winter and spring, die-back of apical shoots occurs in most seedlings owing to weevil attack and fungal infection. Insects may severely damage young leaves, but rapid recovery in full light takes place by the development of axillary and accessory buds. Maximum diameter growth rates tend to occur in November just prior to the main peak of shoot extension. Further increases in diameter may occur in April, and slight shrinkage may take place in late summer and midwinter. The period of active growth can be correlated with the period over which the air temperatures at 1.3 m above ground exceed a daily mean of 5.0-7.5°C, a daily maximum of 12.8° and a weekly maximum exceeding 15.5°. Growth,resumption may be delayed until weekly minimum air tempera- tures rise above - 2°. The mean temperatures at 1.3 m are roughly the mean of air temperatures from the top and base of the shoot. The mean temperatures at the mean commencement and cessation of growth differ by only 0.6-1.6°C, whereas the day length differs by 1½ hr. Growth rates correlate strongly with mean temperatures (particularly mean maximum tempera- tures) in spring and early summer. The wide deviations which occur in late summer and early autumn may be attributable to depletion of soil water reserves.

scholarly journals Growth and Photosynthesis of Magnolia grandiflora `St. Mary' in Response to Constant and Increased Container Volume

1991 ◽  
Vol 116 (3) ◽  
pp. 439-445 ◽  
Author(s):  
Chris A. Martini ◽  
Dewayne L. Ingram ◽  
Terril A. Nell
Keyword(s):  
Carbon Assimilation ◽  
Growing Season ◽  
Limiting Factors ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Magnolia Grandiflora ◽  
Air Temperatures ◽  
Growing Medium ◽  
Early Fall ◽  
The Mean

Growth of Magnolia grandiflora Hort. `St. Mary' (southern magnolia) trees in containers spaced 120 cm on center was studied for 2 years. During the 1st year, trees were grown in container volumes of 10, 27, or 57 liter. At the start of the second growing season, trees were transplanted according to six container shifting treatments [10-liter containers (LC) both years, 10 to 27LC, 10 to 57LC, 27LC both years, 27 to 57LC, or 57LC both years]. The mean maximum temperature at the center location was 4.8 and 6.3C lower for the 57LC than for the 27 and 10LC, respectively. Height and caliper, measured at the end of 2 years, were” greatest for magnolias grown continuously in 27 or 57LC. Caliper was greater for trees shifted from 10LC to the larger containers compared with trees grown in 10LC both years. Trees grown in 10LC both years tended to have fewer roots growing in tbe outer 4 cm of the growing medium at the eastern, southern, and western exposures. During June and August of the 2nd year, high air and growth medium temperatures may have been limiting factors to carbon assimilation. Maintenance of adequate carbon assimilation fluxes and tree growth, when container walls are exposed to solar radiation, may require increasing the container volume. This procedure may be more important when daily maximum air temperatures are lower during late spring or early fall than in midsummer, because low solar angles insolate part of the container surface.

Temperature and Other Climatic Influences on Shoot Development and Growth of Eucalyptus regnans

1975 ◽  
Vol 23 (1) ◽  
pp. 27 ◽  
Author(s):  
KW Cremer
Keyword(s):  
Growth And Development ◽  
Shoot Growth ◽  
Climatic Factors ◽  
Growing Season ◽  
Height Growth ◽  
Shoot Development ◽  
Positive Relation ◽  
Eucalyptus Regnans ◽  
Air Temperatures ◽  
Growth Of Seedlings

The growth and development of shoots of Eucalyptus regnans F. Muell. trees up to 8 m tall growing in their natural environment in central Tasmania were studied continuously for 3 years and related to climatic factors. The influences of temperature were further investigated by experiments with seedlings in a phytotron. Height growth was practically nil in winter and greatest in summer. Throughout the year weekly rates of height growth were closely related to weekly mean maximum air temperatures, increasing from nil or slight at 10�C to peak rates at the highest temperatures experienced (25°). Substantial diameter increments were observed in all seasons and their relation to temperature was relatively weak. There was no positive relation between weekly growth in height or diameter and weekly precipitation. Bud and shoot growth were characterized by continuity of development of all organs throughout the growing season. The youngest of the leaves and internodes which had emerged before winter from the bud resumed growth in spring, but did not reach the lengths achieved by those leaves and internodes which emerged from the bud after winter. It was only by this morphological feature that the boundaries of the annual shoot were identifiable. In agreement with the field observations, the growth of seedlings in glasshouses was found to be slow at day/night air temperatures of 10/5°C and to increase steeply with temperatures to 24/19°. Amongst the notable morphogenic influences associated with increasing temperatures in the glasshouses were poorer root development relative to top growth, thinner and smaller but more numerous leaves, and shorter and more numerous internodes. The elongation of individual leaves and internodes was faster but considerably less prolonged as temperatures increased. The E. regnans seedlings tested failed to prove thermoperiodically sensitive. It is concluded that the dormancy in shoot development observed in the field during winter is due to quiescence imposed by low temperatures, and that in the Tasmanian environment the pattern of growth and development of the vegetative shoots of E. regnans is directly and predominantly controlled by air temperatures throughout the year.

scholarly journals Seasonal development of iron limitation in the sub-Antarctic zone

2018 ◽  
Vol 15 (14) ◽  
pp. 4647-4660 ◽  
Author(s):  
Thomas J. Ryan-Keogh ◽  
Sandy J. Thomalla ◽  
Thato N. Mtshali ◽  
Natasha R. van Horsten ◽  
Hazel J. Little
Keyword(s):  
Phytoplankton Community ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
Seasonal Development ◽  
Iron Availability ◽  
Iron Supply ◽  
Incubation Experiments ◽  
The Mean ◽  
Iron Addition

Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ; ∼40–45∘ S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, atmospheric deposition, iron scavenging and iron recycling processes. Biological observations utilizing grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine whether iron availability at the time of sampling was sufficient to meet biological demands at different times of the growing season. Here we demonstrate that at the beginning of the growing season, there is sufficient iron to meet the demands of the phytoplankton community, but that as the growing season develops the mean iron concentrations in the mixed layer decrease and are insufficient to meet biological demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from midsummer to late summer, with no differences determined during early summer, suggestive of seasonal iron depletion and an insufficient resupply of iron to meet biological demand. The result of this is residual macronutrients at the end of the growing season and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the SAZ, which can extend into late summer/early autumn, results nonetheless suggest that iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.

Growth and Mortality in an Arctic Intertidal Population of Macoma balthica (Pelecypoda, Tellinidae)

1973 ◽  
Vol 30 (9) ◽  
pp. 1345-1348 ◽  
Author(s):  
Roger H. Green
Keyword(s):  
Growth Rates ◽  
Macoma Balthica ◽  
Dry Weight ◽  
Hudson Bay ◽  
Intertidal Environment ◽  
Air Temperatures ◽  
Proximate Factor ◽  
The Mean ◽  
Intertidal Population ◽  
Annual Mortality

In an arctic intertidal environment on Hudson Bay, Macoma balthica have a higher growth rate at a tidal level of 1.1 m above mean low water than at the mean low water level, in terms of both length and dry weight. Temperature, rather than food, appears to be the primary proximate factor involved, and summer air temperatures play a major role. The estimated growth rates are comparable to reported growth rates for intertidal Macoma populations in Scotland and the Netherlands. A partial life table calculated from the death assemblage indicates that Macoma at 1.1 m above mean low water have an annual mortality which increases from about 20% at age 2 to about 50% at age 7 years.

scholarly journals Global and Regional Comparison of Daily 2-m and 1000-hPa Maximum and Minimum Temperatures in Three Global Reanalyses

2009 ◽  
Vol 22 (17) ◽  
pp. 4667-4681 ◽  
Author(s):  
A. J. Pitman ◽  
S. E. Perkins
Keyword(s):  
Probability Distribution ◽  
Probability Density Functions ◽  
Distribution Functions ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Density Functions ◽  
Regional Comparison ◽  
Probability Distribution Functions ◽  
Air Temperatures ◽  
The Mean

Abstract A comparison of three global reanalyses is conducted based on probability density functions of daily maximum and minimum temperature at 2-m and 1000-hPa levels. The three reanalyses compare very favorably in both maximum and minimum temperatures at 1000 hPa, in both the mean and the 99.7th and 0.3rd percentiles of both quantities in most regions. At 2 m, there are large and widespread differences in the mean and 99.7th percentiles in maximum temperature between the three reanalyses over land commonly exceeding ±5°C and regionally exceeding ±10°C. The 2-m minimum temperatures compare unfavorably between the three reanalyses over virtually all continental surfaces with differences exceeding ±10°C over widespread areas. It is concluded that the three reanalyses are generally interchangeable in 1000-hPa temperatures. The three reanalyses of 2-m temperatures are very different owing to the methods used to diagnose these quantities. At this time, the probability distribution functions of the 2-m temperatures from the three reanalyses are sufficiently different that either the 2-m air temperatures should not be used or all three products should be used independently in any application and the differences highlighted.

scholarly journals Рибогосподарська оцінка товарних триліток галицького коропа

2017 ◽  
pp. 72-76
Author(s):  
І. І. Грициняк ◽  
В. В. Гурбик
Keyword(s):  
Growth Rates ◽  
High Growth ◽  
Fish Farming ◽  
Growing Season ◽  
Experimental Period ◽  
The Body ◽  
Productivity Index ◽  
Main Peak ◽  
Individual Weight ◽  
Fish Productivity

Визначено основні рибогосподарські характеристики триліток галицького коропа, отриманих в умовах ставового вирощування. Екологічні умови під час вирощування триліток галицького коропа були в межах рибницьких вимог. В кінці веґетаційного сезону отримані трилітки характеризувались високою індивідуальною масою. Вихід риб з нагулу коливався від 96 % до 98%. Показник рибопродуктивності перевищив 2 000 кг/га. Інтенсивне підвищення маси тіла рибопосадкового матеріалу у 2015 році зафіксовано протягом другої декади липня, в цей період абсолютний ваговий приріст їх перевищив такий 2016 року майже на 200 г. Основний же пік вагового росту риб у 2016 році спостерігався на початку липня. Найменші показники вагового росту протягом експериментального періоду відмічено у травні. У 2015 році тенденція на спад прослідковується також на початку липня. За показником питомої швидкості росту встановлено пік зростання її у другій декаді липня. Мінімальні величини росту у 2015 році зафіксовані на початку червня. Для характеристики господарської якості галицького коропа проведено оцінку екстер’єрних показників протягом веґетаційного сезону. Виявлено, що трилітки характеризуються високим темпом росту, мають невелику голову та м’ясисту структуру. Трилітки галицького коропа, отримані в ставових умовах Прикарпаття відзначаються високими господарськими показниками як за індивідуальною масою риб, так і за загальною рибопродуктивністю. Галицький короп є високопродуктивним та перспективним об’єктом для подальшого відновлення аборигенного складу культивованих видів риб у ставовому рибництві Прикарпаття. The basic fish-farming characteristics of three-year-old Halych carp, obtained in conditions of staple cultivation, are determined. The ecological conditions during growing trilogy of the Halych carp were within the fishery requirements. At the end of the growing season, the trunks were characterized by a high individual weight. The yield of fish feeding stood from 96 % to 98 %. The fish productivity index exceeded 2,000 kg/ha. The intensive increase in the weight of the body of fish and plant material in 2015 was recorded during the second decade of July, during this period, their absolute weight gain exceeded that in 2016 by almost 200 g. The main peak of the weight increase of fish in 2016 was observed in early July. The smallest weights of growth during the experimental period are noted in May. In 2015, the downward trend is also observed in early July. According to the indicator of specific growth rate, the peak of its growth was set in the second decade of July. Minimum growth rates in 2015 are fixed at the beginning of June. In order to characterize the economic quality of the Galician carp, an assessment of exterior characteristics during the growing season was conducted. Three-year-olds are characterized by high growth rates, have a small head and a fleshy structure. The three-year-olds of Halych carp, obtained in the Precarpathian pond conditions, are characterized by high economic indicators both in terms of the individual weight of fish, and in the overall fish productivity. Halych carp is a highly productive and promising object for further restoration of the aboriginal composition of cultivated fish species in the Precarpathian fish farm.

GROWING SEASONS AND THE CLIMATIC MOISTURE INDEX

1971 ◽  
Vol 51 (3) ◽  
pp. 329-337 ◽  
Author(s):  
W. K. SLY ◽  
W. BAIER
Keyword(s):  
Water Demand ◽  
Summer Precipitation ◽  
Growing Season ◽  
Moisture Index ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Early Fall ◽  
Precipitation Indices ◽  
The Mean ◽  
Moisture Conditions

Climatic moisture indices for a fixed growing season, from May to September, are compared with those for growing seasons defined as the periods when either the mean air temperature in the screen or the soil temperature at a 50-cm depth exceeds 5 C. Indices for the longer growing seasons based on soil and air temperatures have small differences at individual stations, but are larger than those for the May–September period. When arranged according to increasing index values, the orders of the stations are essentially the same when growing seasons are based on soil and air temperatures. These differ from the May–September order only in cases where late spring and early fall rains are heavy in relation to summer precipitation. Indices based on data for the May–September period adequately describe the water demand-water supply relationships during the period in which water deficits develop. When moisture conditions outside the May–September period are needed the accumulated water surpluses should be considered.

scholarly journals Freeze Damage to North American Ginseng

2003 ◽  
Vol 13 (4) ◽  
pp. 697-701 ◽  
Author(s):  
Jan Schooley ◽  
John T.A. Proctor
Keyword(s):  
Lake Erie ◽  
Growing Season ◽  
Panax Quinquefolius ◽  
Root Yield ◽  
Southern Ontario ◽  
Full Extent ◽  
Air Temperatures ◽  
Freeze Damage ◽  
The Mean ◽  
Extensive Damage

The Lake Erie counties of southern Ontario, Canada are the major producers of ginseng (Panax quinquefolius) in North America. In this area there is about 1740 ha (4299.5 acres) of ginseng and an annual production of 1455 t (1603.8 tons). Spring freeze damage to the crop is rare as the mean date of last freeze in spring is 12 May. On 21 May 2002, following three to six nights when air temperatures dropped below freezing, extensive damage to the crop was evident. A survey by the Ontario Ginseng Growers Association showed that 78% of growers had gardens showing freeze damage. The extent of the damage was variable across the growing area, and on individual farms. Most damage to plants occurred in low-lying areas where heavy cold air collected. Recently germinated seedlings that were exposed above the straw mulch were severely damaged, and many did not survive because they did not have leaves and no perennating bud was formed. Damage to 2-year-old plants was expressed as leaves wilting and turning black. In some cases stems froze and the plants toppled. In 3-year-old and older plants, damage was variable with some leaf collapse and stems broken, or damaged with corking-over taking place. Damage to inflorescences ranged from death and abscission, to distorted flowers and shriveled and split peduncles. Plant health was a concern following the freeze episode, and throughout the subsequent growing season. The fungicide fenhexamid received emergency registration to combat recurring problems in Botrytis control. The seed crop for 2002 was light. Damaged seedling gardens were replanted. Older gardens will undergo a period of adjustment. Root yield in 2002 was reduced by 30%, a 500 t (551.1 tons) loss. The full extent of the damage and associated financial implications are unknown and could impact the industry until 2005.

Influence of vegetation cover on thermal regime of mountainous catchments

Biologia ◽  
2006 ◽  
Vol 61 (19) ◽  
Author(s):  
Miroslav Tesař ◽  
Miloslav Šír ◽  
L’ubomír Lichner ◽  
Eva Zelenková
Keyword(s):  
Air Temperature ◽  
Plant Cover ◽  
Soil Surface ◽  
Growing Season ◽  
Water Shortage ◽  
Daily Maximum ◽  
Spruce Forest ◽  
Mean Values ◽  
Vegetation Height ◽  
Air Temperatures

AbstractAir temperature at heights of 5 and 200 cm above soil surface, as well as soil temperature at depths of 15, 30 and 60 cm were studied in the cold climatic zone at three localities (catchments) under different plant cover during the growing season of 2002. The catchments Kout (dead forest), Doupě (clearing) and Stolec (mature spruce forest) are situated in the National Park of the Šumava Mts. (Czech Republic) in elevation of 1105–1330 m a.s.l., in which Kout and Doupě form some small “islands” inside an extensive spruce forest. Plant transpiration was not limited by water shortage in all the three localities. It was found that both soil and air temperatures were influenced with plant cover. In hot and dry days, the extremes in daily and night air temperatures were a function of transpiring vegetation height, with higher daily maximum and lower night minimum for smaller vegetation. For the whole growing season (from 29 July to 10 October 2002), the mean values of air temperature were independent upon the plant cover, but the magnitude of the dispersion variance followed the sequence in ascending order: mature forest-clearing-dead forest.

scholarly journals Past and future snowmelt trends in the Swiss Alps: the role of temperature and snowpack

2021 ◽  
Vol 165 (3-4) ◽  
Author(s):  
Maria Vorkauf ◽  
Christoph Marty ◽  
Ansgar Kahmen ◽  
Erika Hiltbrunner
Keyword(s):  
Snow Depth ◽  
Growing Season ◽  
High Elevation ◽  
Alpine Plants ◽  
Swiss Alps ◽  
Climate Change Scenarios ◽  
Freezing Damage ◽  
Strong Shift ◽  
Air Temperatures ◽  
Early Snowmelt

AbstractThe start of the growing season for alpine plants is primarily determined by the date of snowmelt. We analysed time series of snow depth at 23 manually operated and 15 automatic (IMIS) stations between 1055 and 2555 m asl in the Swiss Central Alps. Between 1958 and 2019, snowmelt dates occurred 2.8 ± 1.3 days earlier in the year per decade, with a strong shift towards earlier snowmelt dates during the late 1980s and early 1990s, but non-significant trends thereafter. Snowmelt dates at high-elevation automatic stations strongly correlated with snowmelt dates at lower-elevation manual stations. At all elevations, snowmelt dates strongly depended on spring air temperatures. More specifically, 44% of the variance in snowmelt dates was explained by the first day when a three-week running mean of daily air temperatures passed a 5 °C threshold. The mean winter snow depth accounted for 30% of the variance. We adopted the effects of air temperature and snowpack height to Swiss climate change scenarios to explore likely snowmelt trends throughout the twenty-first century. Under a high-emission scenario (RCP8.5), we simulated snowmelt dates to advance by 6 days per decade by the end of the century. By then, snowmelt dates could occur one month earlier than during the reference periods (1990–2019 and 2000–2019). Such early snowmelt may extend the alpine growing season by one third of its current duration while exposing alpine plants to shorter daylengths and adding a higher risk of freezing damage.

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