scholarly journals Microclimates and Tree Growth in Three Urban Spaces

1992 ◽  
Vol 10 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Roger K. Kjelgren ◽  
James R. Clark
Keyword(s):  
Tree Growth ◽  
The Other ◽  
Urban Spaces ◽  
Urban Site ◽  
Soil Conditions ◽  
Evaporative Demand ◽  
Diameter Increment ◽  
Shade Acclimation ◽  
Air Temperatures ◽  
Crown Size

Abstract Microclimates characteristic of urban park, plaza, and canyon spaces were related to physiology and growth of even-aged sweetgum (Liquidambar styraciflua L.) street trees. Microclimates, tree growth, and physiological responses were characterized diurnally and seasonally. Park and plaza sites received unobstructed sunlight while the canyon was limited to four hours of direct solar radiation in midsummer. Potential seasonal insolation was 44% of the potential maximum at the canyon and over 90% at the park. Afternoon air temperatures and vapor pressure deficits were somewhat greater at the plaza than the other two sites, and potential pan evaporation was nearly 50% greater over the season. Tree growth at the plaza and canyon acclimated physiologically and developmentally to the prevailing environmental conditions. Thinner leaves and less trunk growth when compared with the park were indications of shade acclimation in the canyon trees. This did not, however, appear to affect crown size or shoot growth of canyon trees. In contrast, plaza trees were sparse and stunted, exhibiting diminished crown size and diameter increment when compared with tree at the other sites. Less favorable water relations suggested that chronically higher evaporative demand and limited soil resources restricted growth of the plaza trees. Park, plaza, and canyon designations of urban spaces can provide a useful framework for predicting microclimatic factors that can affect tree growth for an urban site. Long-term growth and development, however, with in any of these urban spaces will depend on interactions with existing soil conditions.

scholarly journals A comparison of climate simulations for the last glacial maximum with three different versions of the ECHAM model and implications for summer-green tree refugia

2011 ◽  
Vol 7 (1) ◽  
pp. 91-114 ◽  
Author(s):  
K. Arpe ◽  
S. A. G. Leroy ◽  
U. Mikolajewicz
Keyword(s):  
Last Glacial Maximum ◽  
Tree Growth ◽  
Western Europe ◽  
Glacial Maximum ◽  
The Other ◽  
Last Glacial ◽  
Climate Simulations ◽  
Southward Shift ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Model simulations of the last glacial maximum (21 ± 2 ka) with the ECHAM3 T42 atmosphere-only, ECHAM5-MPIOM T31 atmosphere-ocean coupled and ECHAM5 T106 atmosphere-only models are compared. The topography, land-sea mask and glacier distribution for the ECHAM5 simulations were taken from the Paleoclimate Modelling Intercomparison Project Phase II (PMIP2) data set while for ECHAM3 they were taken from PMIP1. The ECHAM5-MPIOM T31 model produced its own sea surface temperatures (SST) while the ECHAM5 T106 simulations were forced at the boundaries by this coupled model SSTs corrected from their present-day biases and the ECHAM3 T42 model was forced with prescribed SSTs provided by Climate/Long-Range Investigation, Mapping, and Prediction project (CLIMAP). The SSTs in the ECHAM5-MPIOM simulation for the last glacial maximum (LGM) were much warmer in the northern Atlantic than those suggested by CLIMAP or Overview of Glacial Atlantic Ocean Mapping (GLAMAP) while the SSTs were cooler everywhere else. This had a clear effect on the temperatures over Europe, warmer for winters in western Europe and cooler for eastern Europe than the simulation with CLIMAP SSTs. Considerable differences in the general circulation patterns were found in the different simulations. A ridge over western Europe for the present climate during winter in the 500 hPa height field remains in both ECHAM5 simulations for the LGM, more so in the T106 version, while the ECHAM3 CLIMAP-SST simulation provided a trough which is consistent with cooler temperatures over western Europe. The zonal wind between 30° W and 10° E shows a southward shift of the polar and subtropical jets in the simulations for the LGM, least obvious in the ECHAM5 T31 one, and an extremely strong polar jet for the ECHAM3 CLIMAP-SST run. The latter can probably be assigned to the much stronger north-south gradient in the CLIMAP SSTs. The southward shift of the polar jet during the LGM is supported by palaeo-data. Cyclone tracks in winter represented by high precipitation are characterised over Europe for the present by a main branch from the British Isles to Norway and a secondary branch towards the Mediterranean Sea, observed and simulated. For the LGM the different models show very different solutions: the ECHAM3 CLIMAP-SST simulation shows just one track going eastward from the British Isles into central Europe, while the ECHAM5 T106 simulation still has two branches but during the LGM the main one goes to the Mediterranean Sea, with enhanced precipitation in the Levant. This agrees with an observed high stand of the Dead Sea during the LGM. For summer the ECHAM5 T106 simulation provides much more precipitation for the present over Europe than the other simulations, thus agreeing with estimates by the Global Precipitation Climatology Project (GPCP). Also during the LGM this model makes Europe less arid than the other simulations. In many respects the ECHAM5 T106 simulation for the present is more realistic than the ECHAM5 T31 coupled simulation and the older ECHAM3 T42 simulation, when comparing them with the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis or the GPCP precipitation data. For validating the model data for the LGM, pollen, wood and charcoal analyses were compared with possible summer-green tree growth from model estimates using summer precipitation, minimum winter temperatures and growing degree days (above 5 °C). The ECHAM5 T106 simulation suggests for more sites with findings of palaeo-data, likely tree growth during the LGM than the other simulations, especially over western Europe. The clear message especially from the ECHAM5 T106 simulation is that warm-loving summer-green trees could have survived mainly in Spain but also in Greece in agreement with findings of pollen or charcoal. Southern Italy is also suggested but this could not be validated because of absence of palaeo-data. Previous climate simulations of the LGM have suggested less cold and more humid climate than that reconstructed from pollen findings. Our model results do agree more or less with those of other models but we do not find a contradiction with palaeo-data because we use the pollen data directly without an intermediate reconstruction of temperatures and precipitation from the pollen spectra.

scholarly journals DRUSKININKŲ MIESTO PLANINĖS ERDVINĖS KOMPOZICIJOS YPATUMAI

2009 ◽  
Vol 33 (1) ◽  
pp. 20-27
Author(s):  
Algimantas Mačiulis
Keyword(s):  
The Other ◽  
Urban Spaces ◽  
Health Resort ◽  
High Rise ◽  
The Town

An unsustainable and resolved plan structure has been formed in Druskininkai. Completed urban spaces can be found only in the old town. The other parts of Druskininkai are dominated by chaotic, uncomplete spaces, which should be improved or formed again. New urban formations, especially high-rise buildings, which were built in the eighth and nineth decades, look aggressive and have changed the silhouette and panoramas of the town. When the Lithuanian independence was restored, Druskininkai, because of its beautiful surroundings, became not only a health resort but a recreational one as well. Santrauka Druskininkuose susiformavo nevientisa, išskaidyta plano struktūra. Senoje miesto dalyje yra daugiau susiformavusių, užbaigtų miesto erdvių, kitose miesto dalyse vyrauja nevisiškai suformuotos ar tiesiog chaotiškos miesto erdvės, kurias būtina tobulinti arba formuoti iš naujo. Aštuntajame devintajame dešimtmečiuose statyti naujieji miesto urbanistiniai dariniai, ypač aukštybiniai pastatai, pasižymintys agresyvia invazija į aplinką, iš pagrindų keitė miesto siluetą, panoramas, labai pažeidė gamtos ir architektūros santykį. Atkūrus Lietuvos nepriklausomybę, šalia gydomosios reabilitacinės funkcijos, išnaudojant dėkingą gamtinę apylinkių situaciją, kurorte kuriama nauja perspektyva – pramoginių paslaugų, turizmo programa.

Particulate organic matter in soil under different management systems in the Brazilian Cerrado

Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 685 ◽  
Author(s):  
Arcângelo Loss ◽  
Marcos Gervasio Pereira ◽  
Adriano Perin ◽  
Fernando Silva Coutinho ◽  
Lúcia Helena Cunha dos Anjos
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
The Other ◽  
Management Systems ◽  
Soil Conditions ◽  
Brazilian Cerrado ◽  
Cerrado Vegetation ◽  
No Till ◽  
Planting System

The combination of the no-till planting system (NTS) and pasture (e.g. brachiaria grass, Urochloa sp.) for livestock production constitutes a crop–livestock integration (CLI) system. CLI systems significantly increase the total organic carbon (TOC) content of soil and the particulate organic carbon (POC) of soil organic matter (SOM). The present study evaluated TOC and the granulometric fractions of SOM under different management systems in a Cerrado area in the state of Goiás. Two areas applying crop rotation were evaluated, one using CLI (corn/brachiaria grass/bean/cotton/soybean planted sequentially) and the other NTS (sunflower/pearl millet/soybean/corn planted sequentially). A third area covered with natural Cerrado vegetation (Cerradão) served as a reference to determine original soil conditions. Soil was randomly sampled at 0–5, 5–10, 10–20, and 20–40 cm. The TOC, POC, and mineral-associated organic carbon (MOC) were assessed, and POC and MOC stocks calculated. The CLI system resulted in greater TOC levels than NTS (0–5, 5–10, and 10–20 cm). Compared with the Cerradão, CLI areas exhibited higher stocks of TOC (at 5–10 and 10–20 cm) and POC (at 0–40 cm). Results obtained for TOC and POC fractions show that land management with CLI was more efficient in increasing SOM than NTS. Moreover, when compared with NTS, the CLI system provided better POC stratification.

scholarly journals Climatic-change implications from long-term (1823-1994) ice records for the Laurentian Great Lakes

1995 ◽  
Vol 21 ◽  
pp. 383-386 ◽  
Author(s):  
R.A. Assel ◽  
D.M. Robertson ◽  
M.H. Hoff ◽  
J.H. Selgeby
Keyword(s):  
Great Lakes ◽  
Climatic Changes ◽  
The Other ◽  
Laurentian Great Lakes ◽  
Great Lakes Region ◽  
Lake Mendota ◽  
Air Temperatures ◽  
The 1960S ◽  
Different Parts

Long-term ice records (1823-1994) from six sites in different parts of the Laurentian Great Lakes region were used to show the type and general timing of climatic changes throughout the region. The general timing of both freeze-up and ice loss varies and is driven by local air temperatures, adjacent water bodies and mixing, and site morphometry. Grand Traverse Bay and Buffalo Harbor represent deeper-water environments affected by mixing of off-shore waters; Chequamegon Bay, Menominee, Lake Mendota, and Toronto Harbor represent relatively shallow-water, protected environments. Freeze-up dates gradually became later and ice-loss dates gradually earlier from the start of records to the 1890s in both environments, marking the end of the “Little lce Age”. After this, freeze-up dates remained relatively constant, suggesting little change in early-winter air temperatures during the 20th century. Ice-loss dates at Grand Traverse Bay and Baffalo Harbor but not at the other sites became earlier during the 1940s and 1970s and became later during the 1960s. The global warming of the 1980s was marked by a trend toward earlier ice-loss dates in both environments.

scholarly journals Biogeochemical Processes of C and N in the Soil of Mangrove Forest Ecosystems

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 492 ◽  
Author(s):  
Yo-Jin Shiau ◽  
Chih-Yu Chiu
Keyword(s):  
Climate Change ◽  
Mangrove Forest ◽  
Plant Biomass ◽  
Chemical Elements ◽  
Soil Conditions ◽  
Mangrove Forests ◽  
Biogeochemical Processes ◽  
C Storage ◽  
Air Temperatures ◽  
C And N

The mangrove forest provides various ecosystem services in tropical and subtropical regions. Many of these services are driven by the biogeochemical cycles of C and N, and soil is the major reservoir for these chemical elements. These cycles may be influenced by the changing climate. The high plant biomass in mangrove forests makes these forests an important sink for blue C storage. However, anaerobic soil conditions may also turn mangrove forests into an environmentally detrimental producer of greenhouse gases (such as CH4 and N2O), especially as air temperatures increase. In addition, the changing environmental factors associated with climate change may also influence the N cycles and change the patterns of N2 fixation, dissimilatory nitrate reduction to ammonium, and denitrification processes. This review summarizes the biogeochemical processes of C and N cycles in mangrove forest soils based on recently published studies, and how these processes may respond to climate change, with the aim of predicting the impacts of climate change on the mangrove forest ecosystem.

scholarly journals Large daytime signals of N<sub>2</sub>O<sub>5</sub> and NO<sub>3</sub> inferred at 62 amu in a TD-CIMS: chemical interference or a real atmospheric phenomenon?

2014 ◽  
Vol 7 (1) ◽  
pp. 1-12 ◽  
Author(s):  
X. Wang ◽  
T. Wang ◽  
C. Yan ◽  
Y. J. Tham ◽  
L. Xue ◽  
...  
Keyword(s):  
Hong Kong ◽  
Atmospheric Chemistry ◽  
Thermal Dissociation ◽  
Measurement Techniques ◽  
The Other ◽  
Urban Site ◽  
Ionization Mass ◽  
Mixing Ratios ◽  
Other Hand ◽  
Interference Tests

Abstract. Dinitrogen pentoxide (N2O5) and the nitrate radical (NO3) play important roles in atmospheric chemistry, yet accurate measurements of their concentrations remain challenging. A thermal dissociation chemical ionization mass spectrometer (TD-CIMS) was deployed to an urban site in Hong Kong to measure the sum of N2O5 and NO3 in autumn 2010 based on the signals of NO3− at 62 amu which has also been adopted in previous studies reported in literature. To our surprise, very large signals of N2O5 + NO3 were frequently observed at 62 amu in the daytime, with equivalent N2O5 + NO3 mixing ratios in the range of 200–1000 pptv. To investigate this unusual phenomenon, various interference tests and measurements with different instrument configuration were conducted. It was found that peroxy acetyl nitrate (PAN) contributed to measurable signals at 62 amu, and more importantly, this interference increased significantly with co-existence of NO2. Nitric acid (HNO3), on the other hand, had little interference to the detection of N2O5/NO3 via the NO3− ion in our TD-CIMS. According to the test results, the interference from PAN and NO2 could have contributed to 30–50% of the average daytime (12:00–16:00, local time) N2O5 + NO3 signal at our site. On the other hand, evidence exists for the presence of elevated daytime N2O5, in addition to the daytime signal at 62 amu. This includes (1) daytime N2O5 measured via the I(N2O5)− cluster ion with an unheated inlet, which was subjected to minimum interferences, and (2) observation of elevated daytime ClNO2 (a product of N2O5 hydrolysis) during a follow-up study. In view of the difficulty in accurately quantifying the contribution from the interferences of PAN and NO2 and untested potential interfering chemicals in the real atmosphere, we caution the use of 62 amu in the TD-CIMS for measuring ambient N2O5 in a high NOx environment like Hong Kong. Additional studies are needed to re-examine the daytime issue using other measurement techniques.

ECOLOGICAL STUDY OF THE PEAT BOGS OF EASTERN NORTH AMERICA: III. NOTES ON THE BEHAVIOR OF CHAMAEDAPHNE CALYCULATA

1956 ◽  
Vol 34 (1) ◽  
pp. 197-207 ◽  
Author(s):  
Kornelius Lems
Keyword(s):  
Ecological Study ◽  
The Other ◽  
Soil Conditions ◽  
Peat Bogs ◽  
Eastern North America ◽  
Physiological Basis ◽  
Chamaedaphne Calyculata ◽  
Different Types ◽  
The One ◽  
The Relationship

This paper presents data and observations concerning Chamaedaphne calyculata (L.) Moench. (Ericaceae). The branching pattern, the longevity of different types of leaves, and features of flowering are shown to be correlated. The relationship between this complex of features and the habitat is studied, and a few speculations are advanced to explain the physiological basis for the behavior of Chamaedaphne. This study is essentially autecological, and it is hoped that it may constitute a link between the study of soil conditions and the response of plant hormones on the one hand, and phytosociological work in peat bogs on the other hand.

scholarly journals Photosynthetic performance of rock-colonising lichens in the Mountain Zebra National Park, South Africa

Koedoe ◽  
1993 ◽  
Vol 36 (1) ◽  
Author(s):  
Dirk Wessels ◽  
Ludger Kappen
Keyword(s):  
South Africa ◽  
Volcanic Rock ◽  
National Park ◽  
Ambient Air ◽  
Early Morning ◽  
Photosynthetic Performance ◽  
The Other ◽  
Air Temperatures ◽  
Desert Regions

The photosynthetic behaviour of endolithic andepilithic lichens characteristic of sedimentary and volcanic rock was investigated in situ in the Mountain Zebra National Park, South Africa. The park forms part of an inland semi-desert known as the Karoo, in the Cape Province. Temperatures within Balfour sandstone were monitored, the results showing that during the early morning, temperatures within the sandstone were nearly 5@C lower than ambient air temperatures. This may enhance the frequency of water condensing on the sandstone, which may be particularly important for the endoliths Leciclea aff. sarcogynoides and Sarcogyne cf. austroafricana. Maximum photosynthetic rates of the investigated species were found at temperatures between 20@C and 30@C, far higher than the recorded optimum temperatures for lichens from temperate and desert regions. Parmelia chlorea was the most productive species. Compared to the other epiliths, Peltula capensis was found to be a moderately productive species. The photosynthetic gain of Leciclea aff. sarcogynoides and Sarcogyne cf. austro-africana was low, but the photosynthetic gain of these two species still exceeded that of Acarospora sp.

Efficiency of Grasshopper Baits in Relation to Time of Day of Application

1952 ◽  
Vol 84 (5) ◽  
pp. 147-155 ◽  
Author(s):  
R. H. Handford ◽  
L. G. Putnam
Keyword(s):  
Experimental Data ◽  
Surface Temperature ◽  
Air Temperature ◽  
Soil Surface ◽  
Time Of Day ◽  
Rapid Decrease ◽  
The Other ◽  
Feeding Period ◽  
Air Temperatures ◽  
Soil Surface Temperature

Literature on grasshopper control published hetween 1930 and 1942 stressed the desirability of applying poisoned bait when grasshoppers begin their first main feeding period of the day. Such pubiications include those by Parker (1930). Parker, Walton, and Shotwell (1932), Criddle (1932). Ruggles and Aamodt (1938), and Bird (1940). Parker (1930) found that the lesser migratory grasshopper, Melanoplus mexicanus mexicanus (Sauss.), fed sparingly on baits at air temperatures between 55°F. and 63°F., more actively between 64°F. and 67°F., and most actively between 68°F. and 78°F. A rapid decrease in feeding occurred when air temperature rose above 80°F. or the soil surface temperature above 113°F. Much the same relationship held also for the clear-winged grasshopper, Cammula pellucida (Scudd.). On the basis of such observations it was decided chat an air temperature of 68°F. might be classed as optimum for beginning the application of bait. Parker did not, however, indicate the degree of mortality resulting from such feeding; the other writers gave no experimental data.

scholarly journals Some effects of high air temperatures and muscular exertion upon colliers

1923 ◽  
Vol 95 (666) ◽  
pp. 181-200 ◽  
Keyword(s):  
Food Consumption ◽  
High Temperatures ◽  
Royal Society ◽  
The Other ◽  
Research Student ◽  
Muscular Exertion ◽  
Temperature Conditions ◽  
Air Temperatures

This paper deals with the work undertaken by the author while he was Tyndall Research Student of the Royal Society. The investigations fall under the following four distinct headings:— 1. The Food Consumption of Colliers and its relation to Underground temperature conditions. 2. Respiratory Exchange of a Collier during work. 3. Relation of High Temperatures and Work to Sweating. 4. Miners’ Cramp. Each branch of investigation is related to underground temperature conditions, and has in consequence a bearing upon each of the other sections.

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