Ecological Consequences of the Replacement of Native Grassland by Juniperus virginiana and Other Woody Plants

Author(s):  
Alan K. Knapp ◽  
J. K. McCarron ◽  
A. M. Silletti ◽  
G. A. Hoch ◽  
J. C. Heisler ◽  
...  
Author(s):  
V. O. Kornienko

It has been experimentally found that the mono groups of Juniperus virginiana L. have less resistance to the natural and climatic factors, this is firstly due to increase in the height of biomass of the tree and secondly to application of loads in the form of a wind force, as well as an additional mass in precipitation. According to the results of diagnostics of the state and monitoring of sustainability of Juniperus virginiana L.plantings, the accident risk is estimated at 14% of the total number (585 units).


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242003
Author(s):  
David Ward

The expansion of woody plants into grasslands and old fields is often ascribed to fire suppression and heavy grazing, especially by domestic livestock. However, it is also recognized that nutrient availability and interspecific competition with grasses and other woody plants play a role in certain habitats. I examined potential factors causing range- and niche expansion by the eastern redcedar Juniperus virginiana, the most widespread conifer in the eastern United States, in multifactorial experiments in a greenhouse. Historical records suggest that the eastern redcedar is a pioneer forest species, and may be replaced as the forest increases in tree density due to shading. Another possible factor that affects its distribution may be nutrient availability, which is higher in old fields and other disturbed lands than in undisturbed habitats. In its historic range, eastern redcedars are particularly abundant on limestone outcrops, often termed ‘cedar barrens’. However, the higher abundance on limestone could be due to reduced interspecific competition rather than a preference for high pH substrates. I manipulated shade, fertilization, lime, and interspecific competition with a common dominant tree, the post oak Quercus stellata. In a separate experiment, I manipulated fire and grass competition. I measured growth rates (height and diameter) and above- and belowground biomass at the end of both experiments. I also measured total non-structural carbohydrates and nitrogen in these plants. Shade was the most important factor limiting the growth rates and biomass of eastern redcedars. I also found that there were significant declines in nitrogen and non-structural carbohydrates when shaded. These results are consistent with the notion that the eastern redcedar is a pioneer forest species, and that shade is the reason that these redcedars are replaced by other tree species. In the second experiment, I found that a single fire had a negative effect on young trees. There was no significant effect of competition with grass, perhaps because the competitive effect was shading by grasses and not nutrient depletion. Overall, the effects of shade were far more apparent than the effects of fire.


2021 ◽  
pp. 17-32
Author(s):  
А.В. Семенютина ◽  
М.В. Цой ◽  
В.В. Сапронов

В Волгоградской области единственным аборигенным представителем хвойных древесных растений является J. sabina L., существования популяции одного представителя хвойных свидетельствует об однородности дендрофлоры, что может привести к деструкции экосистемы в целом. Интродукция растений как инструмент на пути к достижению биоразнообразия дендрофлоры, является наиболее практичным и перспективным методом в условиях сухой степи. Целью исследования, являлось проведение биоэкологической оценки и жизненного состояния хвойных древесных растений, а также определение степени интродукционной устойчивости условиях сухой степи. Проведена оценка шести интродуцированных древесных растений в дендроколлекциях ФНЦ Агроэкологии РАН: Juniperus virginiana L., J. communis L., J. sabina L., Thuja occidentalis L, Platycladus orientalis(L.) Franco, Pseudotsuga menziesii (Milb) Franco. Определены сроки наступления и длительность основных фенологических фаз методикой фенологических наблюдений ГБС. При отклонении среднегодовой температуре воздуха выше нормы на 1,05 ºС и годовой суммы осадков 75% от нормы, длительность проявления периода вегетации составила у J. sabina L. – 58 дней, самый короткий период у J. communis L. – 41 день, Pseudotsuga menziesii (Milb) Franco 55 дней, J. virgiana L. – 56 дней, T. occidentalis L. – 71 день, P. orientalis (L.) Franco – 68 дней. В рамках эколого-биологической оценки были исследованы такие показатели как зимостойкость, засухоустойчивость, характер пыления и семеношения. Отдельно был исследован семенной материал методом определения массы 1000 семян. Также была дана оценка декоративности, по которой определялась специфика применения того или иного вида для целей озеленения. В результате проведенных исследований рассчитали значения акклиматизационного числа для каждого вида, по которому определена степень интродукционной устойчивости в условиях сухой степи. В ходе проделанной работы даны практические рекомендации по посадке хвойных деревьев кустарников для целей озеленения. In the Volgograd region, the only native representative of coniferous woody plants is J. sabina L., the existence of a population of one representative of coniferous plants indicates the homogeneity of the dendroflora, which can lead to the destruction of the ecosystem as a whole. Plant introduction as a tool on the way to achieving dendroflora biodiversity is the most practical and promising method in the conditions of the dry steppe. The aim of the study was to conduct a bioecological assessment of the life condition of coniferous woody plants, as well as to determine the degree of introduction resistance in the conditions of the dry steppe. Six introduced woody plants were evaluated in the dendrocollections of the Federal Research Center of Agroecology of the Russian Academy of Sciences: Juniperus virginianaL., J. communis L., J. sabina L., Thuja occidentalis L, Platycladus orientalis (L.) Franco, Pseudotsuga menziesii (Milb) Franco. The timing of the onset and duration of the main phenological phases were determined by the method of phenological observations of HBS. With the deviation of the average annual air temperature above the norm by 1.05 ° C and the annual precipitation of 75% of the norm, the duration of the vegetation period was 58 days for J. sabina L., 41 days for J. communis L., 55 days for Pseudotsuga menziesii (Milb) Franco, 56 days for J. virgiana L., 71 days for T. occidentalis L., and 68 days for P. orientalis (L.) Franco. As part of the ecological and biological assessment, such indicators as winter hardiness, drought resistance, the nature of dusting and seed-bearing were studied. Separately, the seed material was examined by the method of determining the mass of 1000 seeds. There was also an assessment of decorativeness, which determined the specifics of the use of a particular type for landscaping purposes. As a result of the conducted studies, the values of the acclimatization number for each species were calculated, according to which the degree of introduction resistance in the conditions of the dry steppe was determined. In the course of the work done, practical recommendations are given for planting coniferous trees and shrubs for landscaping purposes.


Author(s):  
Д.В. Сапронова ◽  
А.А. Долгих ◽  
М.В. Цой ◽  
В.В. Сапронов

В связи с реализацией мероприятий национальных проектов «Наука», «Экология» остро стоят вопросы обеспечения посадочным материалом адаптированных древесных видов лесовосстановительных работ на деградированных территориях засушливых территорий. Цель исследований – разработка перспективных технологий размножения хвойных таксонов для лесомелиорации и озеленения с учетом их репродуктивных особенностей в засушливых условиях. Объекты исследований: лжетсуга Мензиеза (Pseudotsuga menziesii (Mirb.) Franco.), можжевельник виргинский (Juniperus virginiana L.), м. казацкий (sabinaL.), туя западная (Thuja occidentalis L.), плосковеточник восточный (Platycladus orientalis (L.) Franco), ель колючая ф. сизая (Picea pungens Engelm f. glauca Beissn.) коллекций, питомников, маточников Нижневолжской станции по селекции древесных пород – филиала ФНЦ агроэкологии РАН (кадастр. № 34:36:000014:178). Научные исследования направлены на решение теоретических и методических вопросов получения посадочного материала из адаптивного поколения древесных растений на основе изучения их репродуктивной способности. Выявлено качественные и количественные параметры семеношения и влияние лимитирующих факторов среды на развитие семян. Установлены особенности семенного размножения представителей древесных растений (хвойные таксоны) и разработаны технологические аспекты вегетативного размножения в условиях питомника Нижневолжской станции по селекции древесных пород (Волгоградская обл., Камышин) и комплекс мероприятий, обеспечивающих выращивание стандартного посадочного материала за один вегетационный период. Этот важный технологический прием в 2,8 раза увеличивает выход сеянцев с единицы площади, 87 % сеянцев достигают стандартных размеров, в 6 раз увеличивается абсолютно сухая масса сеянца. Внедрение научных разработок проводилось на производственных питомниках Нижневолжской станции по селекции древесных пород. В 2019 году было реализовано сеянцев и саженцев на сумму 6771024,12 рублей. Даны прогнозные предложения по развитию объекта – обновление производственной инфраструктуры станции, в т.ч. реконструкция питомника с целью формирования фонда посадочного материала для воспроизводства и использования коллекций биоресурсов деревьев и кустарников многоцелевого назначения. In connection with the implementation of the activities of the national projects "Science" and "Ecology", there are urgent issues of providing planting material for adapted wood types of reforestation in degraded areas of arid territories. The aim of the research is to develop promising technologies for breeding coniferous taxa for forest reclamation and landscaping, taking into account their reproductive characteristics in arid conditions. Research objects: Pseudotsuga menziesii (Mirb.) Franco.), Virginia juniper(Juniperus virginiana L.), M. kazatsky (J. sabina L.), Western thuja (Thuja occidentalis L.), Eastern flatwort (Platycladus orientalis (L.) Franco), prickly spruce (Picea pungens Engelm f. glauca Beissn.) collections, nurseries, brooders of the Nizhnevolzhskaya station for the selection of tree species – branch of the Federal Scientific Centre of Agroecology of the Russian Academy of Sciences (cadastre. № 34:36:000014:178). Scientific research is aimed at solving theoretical and methodological issues of obtaining planting material from the adaptive generation of woody plants based on the study of their reproductive ability. The qualitative and quantitative parameters of seed production and the influence of limiting environmental factors on the development of seeds were revealed. The features of seed reproduction of representatives of woody plants (coniferous taxa) and the technological aspects of vegetative propagation in a kennel Nizhnevolzhsky station on selection of tree species (Volgograd region, Kamyshin) and a set of activities to ensure the cultivation of standard planting material for one growing season. This important technological technique increases the yield of seedlings per unit area by 2.8 times, 87 % of seedlings reach standard sizes, and the absolutely dry weight of the seedling increases by 6 times. The introduction of scientific developments was carried out at the production nurseries of the Nizhnevolzhskaya station for the selection of tree species. In 2019, seedlings and saplings were sold for the amount of 677,1024. 12 rubles. Forecast proposals for the development of the facility are given – updating the production infrastructure of the station, including the reconstruction of the nursery in order to form a Fund of planting material for the reproduction and use of collections of bioresources of trees and shrubs for multi-purpose purposes.


1989 ◽  
Vol 7 (2) ◽  
pp. 77-78
Author(s):  
Tom Ness
Keyword(s):  

2014 ◽  
Vol 26 (3-4) ◽  
pp. 42-61
Author(s):  
O. G. Lucyshyn ◽  
I. K. Teslenko

The recent ecological situation of Kyiv megalopolis has a special specific of environment technogenic pollution as a chemical features and content of polluting phytotoxicants. During 2007–2012, our observation revealed what the most dangerous factors which have harm impact on the street woody plants are the huge concentration of phytotoxic elements (Na+, Cl-, Pb2+, Cd2+). Nowadays, the technogenic impact on the megalopolyisis surrounding comes to the dangerous, even, catastrophic level. The main reason of total and chloral necrose of leaves, the summer defoliation of crown and major tree's death is the over pollution of the soil and plant's phytomass by phytotoxic elements, the concentration of which by standards evaluation and by trees reactions are critical and exists at the level of adaptation possibility and survival. The main sources of Pb2+ and Cd2+ ions are transport outcomes (> 90 % of total technogenic pollution). The increasing of Pb2+ and Cd2+ in the soil is depended from intensivity of transport outcomes, using of ethylated petrol, and location of trees along roads as well as from the trees species. Continuously increasing of number of cars at the city streets is accompanying with similar increasing of ions concentration. Thus, in the soil around root system of street woody plants, depending from their location along roads, the concentration of Pb2+ (moving form) is between 41,7 (I. Kudri str.) and 102,6 mg\kg of soil (Nauki avenue). It exceeds the maximum permissible concentration (MPC), which is 20,8–51,3 mg\kg of soil. Next, for Norway maple (Acer platanoides) the concentration of Pb2+ in the soil varies from 41,7 to 80,5 mg / kg of soil in the area of the root system and it is around 20,8–40,2 MPC. In the leaves of this tree it is 7,83–13,5 mg / kg of dry mass (MPC is 15,8–27,0). For the horse chestnut (Aedculus hippocastanum) at the Nauka avenue, the concentration of plumbum in the root is 13,4 mg / kg (MPC is 26,8), in the cortex – 17,7 mg / kg (MPC is 35,4), in leaves – 8,21 mg / kg (MPC is 16,4), which by the normative evaluation are the critical concentrations. The source of Na+ and Cl-, which is a new factor for Kyiv megalopolis, is irregular load of high concentrations of industrial salt NaCl into the environment, as a way against black ice in winter time, where the Na+ ions ( mobile form) is in the high concentrations in leaves (0,76 % for Norway maple (Acer platanoides) on the I. Kudri str., 1,28 % – small-leaved linden (Tilia cordata) at the 40-richya Zhovtnya ave, 2,0 % – horse chestnut (Aedculus hippocastanum) at the Nauki ave), those are exceeded the concentration of the element comparing to the control test object, respectively, in 10,6, 12,8 and 5,0 times. Na+ ions are an aggressive phytotoxins and the main factor of leaves necrose of tree crown (within 70–100 % necrosis leaves in the crown). Degradation and total reduction of the specific weight of plants in the megalopolis environment are decrease the cleaning role of the street tree plants, which are the main alive filters for soil and air cleaning, as well as the main bioaccumulators and detoxicants of harm substances of anthropogenic pollution. Species adaptive specificity is revealed at the bioaccumulation level and the selective locality of phytotoxic elements (Na+, Cl-, Pb2+, Cd2+, agile form) in technourbanhabitats-pic conditions, there dominated bioaccumulation and localization of Na+ ions by trees assimilative system is caused the adaptive orientation of endogenic and intraspecific variability of phytoindicative morphophysiologic features of plants functional condition under the stressing factors. This also is defined the sensitivity of small-leaved linden (Tilia cordata Mill.), norway maple (Acer platanoides L.) and horse chestnut (Aesculus hippocastanum L.) to the big concentration of potassium as the most danger one for the plant survival. The biggest accumulation of Na+ ions at the roots of Lombardy poplar (Populus pyramidalis Roz.), Bolle's poplar (Populus bolleana Lauche) and sugar maple (Acer saccharinum L.) is lead to a higher resistance of their assimilation system. At the technourbohabitate-pic conditions, the level of realization of ontogenetic and phylogenetic adaptive capacity of the sensitive species of trees is harmfully low (21,3–44,3 %). It is at the level of survival/death of plants. The street Lombardy poplar, Bolle's poplar and sugar maple, despite of more higher level of their adaptation (68,4–87,7 %), still also can't fully adapt to the critical levels of technogenic pollution of megalopolis environment. 


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