Cent Of Area Research Articles

A small-scale landslide susceptibility assessment for the territory of Western Carpathians

This study presented herein compares the bivariate and multivariate landslide susceptibility mapping methods and presents the landslide susceptibility map of the territory of Western Carpathians in small scale. This study also describes pioneer work for the territory of Western Carpathians, overreaching state borders, using verified sophisticated statistical methods. In the susceptibility mapping, digital elevation model was first constructed using a GIS software, and parameter maps affecting the slope stability such as geology, seismicity, precipitation, topographical elevation, slope angle, slope aspect and land cover were considered. In the last stage of the analyses, landslide susceptibility maps were produced using bivariate and multivariate analyses, and they were then compared by means of their validations. The validation of the bivariate analysis data was performed using the results of bivariate analysis for landslide areas of Slovakia containing five classes of susceptibility in scale 1:500,000. The validation area is the area of Western Carpathians within Slovakia. Eighty-two per cent of area does not differ in more than one class. The validation of the multivariate analysis data was performed using the results from the Kysuce region in the northern part of Slovakia in scale 1:10,000. The raster calculator was used to express the difference between each pair of pixels within these two layers. Seventy-seven per cent of the pixels do not differ in more than 25 %, 94 % of the pixels do not differ in more than 50 %. The maximal possible difference is 100 % (one pixel with value 0 and other with value 1, or vice versa). Receiver operating characteristic analysis was also performed, the area under curve value for bivariate model was calculated to be 0.735, while it was 0.823 for multivariate. The results of the validation can be considered as satisfactory.

Land suitability studies for major crops in Pavagada taluk, Karnataka using remote sensing and GIS techniques

Pavagada taluk of Tumkur district in Karnataka is one of the most backward taluks receiving less than 500 mm annual rainfall. The maximum area of the taluk is under monocropping, reasons for the same were not documented well. The present study was carried out using remote sensing data along with field survey and laboratory analysis for assessing the potentials and limitations of soil. Using the basic information on soil, climate and topography based on the matching exercise between the growth and production requirements of the crop, suitability of soils for groundnut, paddy and finger millet was assessed as per FAO land evaluation. The soil suitability maps were prepared using Arc GIS software. About 48 per cent of the total area was moderate to marginally suitable and 13 per cent of the area was not suitable for both groundnut and finger millet. Lowland areas covering 12 per cent of the area was highly suitable, 15 per cent was moderate to marginally suitable and 20 per cent was not suitable for paddy cultivation.

Cx43 CT domain influences infarct size and susceptibility to ventricular tachyarrhythmias in acute myocardial infarction

Hearts of mice expressing K258stop in place of connexin43 (Cx43) protein were subjected to acute myocardial infarction in order to assess the importance of Cx43 regulation on infarct size and arrhythmia susceptibility. This mutation K258stop prevents chemical regulation of Cx43 channels, including by low intracellular pH. Langendorff-perfused hearts of mice harbouring one Cx43 knockout (KO) allele and one K258stop or Cx43 allele (K258stop/KO; Cx43/KO as control) were subjected to 1 h of ischaemia and 4 h of reperfusion by reversibly occluding the left anterior descending (LAD) coronary artery. Inducibility of ventricular tachyarrhythmias (VTs) was tested by applying an endocardial burst-pacing protocol during LAD occlusion. Separately, time course and the extent of acidification-induced closure of gap junction channels were tested by dual-voltage clamp. Infarct volume (as per cent of area at risk) was significantly larger in K258stop/KO hearts compared with Cx43/KO controls (42.2 +/- 3 vs. 30.4 +/- 1.7%, P = 0.004, n = 8 each). During LAD occlusion, K258stop/KO hearts had a higher incidence of pacing-induced VT and a higher frequency of occurrence of spontaneous premature ventricular beats. The occurrence of ventricular arrhythmias was also significantly larger in the K258stop/KO hearts during reperfusion. In separate experiments, we demonstrated reduced sensitivity to acidification-induced uncoupling in cell pairs obtained from K258stop/KO hearts. Loss of the regulatory domain of Cx43 leads to an increase in infarct size and increased susceptibility to arrhythmias following acute coronary occlusion.

Land degradation mapping in the upper catchment of river Tons

A study on land degradation in the upper catchment of river Tons, a tributary of Yamuna river, in Uttarkashi district of the Uttarakhand state, was carried out using on-screen visual interpretation of IRS LISS-III + PAN merged data. The study area, which is largely mountainous, includes Govind Wildlife Sanctuary and National Park. Vegetation cover, slope and erosion status were used as criteria for the delineation of four major land degradation categories viz., undegraded, moderately degraded, degraded and severely degraded. More than 50 per cent of the study area is reported to be covered with snow and grassland. The moderate to severely degraded area worked out to be 42.4 per cent of the total area. The 32.8 per cent of area was found to be moderately degraded, followed by degraded (6.63%) and severely degraded (2.88%) areas. The depletion of vegetation cover on mountainous terrain and subsequent cultivation without proper protection measures is the reason for severe soil erosion and land degradation. In view of the existing land degradation situation, the catchment requires immediate treatment on priority for the sustenance of agriculture and wild life. It is expected that these measures will reduce the silt load in the river Tons and eventually, in river Yamuna.

Long-term spatio-temporal dynamics and historical continuity of European aspen (Populus tremula L.) stands in the Koli National Park, eastern Finland

Summary Although the European aspen ( Populus tremula L.) is regarded as a keystone species for the biodiversity of northern Europe, its mechanisms of regeneration and persistence under old-growth conditions without large-scale disturbances have remained obscure. The aim of this paper is to describe the long-term dynamics and regeneration of European aspen in the old-growth forests of the Koli National Park, eastern Finland, in order to gain a better understanding of the occurrence of this species under natural forest conditions. The park includes both natural forests and forests that were previously managed. The long-term occurrence of aspen populations was determined on the basis of inventory data available for the years 1910, 1936 and 2004. Aspen is shown to have occurred at least temporarily over 34 per cent of the total forest area (840 ha). In addition, 13 per cent of the forest area continuously supported stands that contained large aspen trees between 1910 and 2004. In areas where no management took place (6.4 per cent of the area), about one-third of all the aspen stands contained large trees and persisted throughout the period. The results show that aspen can maintain long-term occurrence in old-growth forests and that the species is not only transient or confi ned to young successional stages. Areas where aspen regeneration is possible, as deduced from its long-term occurrence should be regarded as highly valuable for biodiversity because they offer long-term habitats for several threatened species that are associated with aspen trees. Recent changes in ecological conditions, however, may affect this in the future. Most notably, the increased population of large mammalian browsers may make aspen regeneration more diffi cult and should be taken into account when restoration and management measures are planned.

Rubber Plantations: Growth and Prospects of Small Holders

Plantations form the most commercialised sub-sector of the agricultural sector. They have many of the industrial characteristics that qualify them to be categorised as ‘plantation industry’. The rubber plantation industry' in India includes both well organised estates and scattered small holdings*. The state of Kerala and the Kanyakumari District of the state of Tamil Nadu together constitute the traditional rubber growing region in the country. This region accounted for as much as 88 per cent of the total area of5,74.000 hectares cultivating rubber as at the end of2003-04. Small holding sector, comprising of 9.92 lakh units with the average size of less than half a hectare, dominates the production sector by sharing as much as 88 per cent of area and production. Though size constrained, more than 98 per cent of the total area in small holding sector is occupied by high yielding cultivars and the sector is much ahead in adopting short term productivity enhancement measures. The good status of the dominant small holding sector in adopting frontier technologies is a crucial factor determining the aggregate productivity of Natural Rubber in the country. India’s productivity of natural rubber, measured in terms of average yield from unit hectare, which was 1,663 Kg during 2003-04, is the highest among the major rubber producing countries.

Les ressources en eau dans les forêts de Bavière Observations qualitatives et démarches protectrices

Click to increase image sizeClick to decrease image sizeIn Bavaria the drinking water supply mainly uses groundwater, only one third of which has to be treated before usage. Overall groundwater protection is the best strategy to preserve this situation. Moreover till now 3.5 per cent of the state area has been arranged as water protection area with specific demands on landuse practices. About 50 per cent of this area is covered with forest, compared with 33 per cent in the whole country. Diverse impacts on the forest, i.e. deposition of atmospheric pollutants, extensive damages or special forms of wood harvesting can endanger groundwater quality, which is generally high up to now. In Bavaria, groundwater acidification has occurred in some specific areas, whereas the potential risk of increased nitrate leaching under forest stands is widespread. Therefore the Bavarian water authorities support all efforts made by the forest administration to increase the portion of stabile, deciduous forests and to support groundwater protecting practices in forest management.

Role of protein kinase C in the reduction of infarct size by N-methyl-1-deoxynojirimycin, an alpha-1,6-glucosidase inhibitor.

Preischaemic treatment with N-methyl-1-deoxynojirimycin (MOR-14), an alpha-1,6-glucosidase inhibitor, attenuates glycogenolysis and lactate accumulation during ischaemia and markedly reduces infarct size in rabbit hearts. In the present study, we have investigated whether protein kinase C (PKC), a principal mediator of ischaemic preconditioning, is also involved in the cardioprotective effect of MOR-14. To assess the effect of PKC inhibition on infarct size in MOR-14-treated hearts, 38 rabbits were subjected to 30 min of ischaemia followed by 48 h of reperfusion. Infarct size, as a per cent of area at risk, was significantly smaller in rabbits administered 100 mg kg(-1) of MOR-14 10 min before ischaemia (17+/-2%, n=10), than in a control group (46+/-5%, n=10). This beneficial effect of MOR-14 was abolished when 5 mg kg(-1) of chelerythrine, a PKC inhibitor, was given 10 min prior to MOR-14 injection (39+/-4%, n=10), although chelerythrine alone did not alter infarct size (43+/-4%, n=8). Further, chelerythrine had no effect on MOR-14-induced attenuation of glycogen breakdown and lactate accumulation in hearts excised at 30 min of ischaemia. Immunoblot analysis of PKC in homogenates of Langendorff-perfused rabbit hearts revealed that MOR-14 significantly increased levels of PKC-epsilon in the particulate fraction at 20 and 30 min of ischaemia and in the cytosolic fraction at 30 min of ischaemia. Taken as a whole, our data suggest that PKC acts downstream of the inhibition of glycogenolysis by MOR-14 to reduce infarct size. Thus, activation of PKC is a more direct mediator of the cardioprotection afforded by MOR-14 than is inhibition of glycogenolysis.

The effect of remineralization on artificial caries-like lesions and their crystal content

Exposure of both small carious lesions and artificial caries-like lesions to a synthetic calcifying fluid in vitro produced a significant degree of remineralization of the lesion. Changing the calcium concentration of the calcifying fluid had a marked effect on the degree of remineralization produced. Only the apatite phase was supersaturated in the 1 mM Ca calcifying fluid while the 3 mM Ca calcifying fluid was supersaturated with respect to several more acidic calcium phosphate phases. With the 3 mM Ca calcifying fluid the higher supersaturation allowed the formation of precursor phases which blocked surface pores limiting penetration. This was confirmed by the appearance of clusters of plate-like crystals in the immediate surface layer, a feature not found with the 1 mM Ca calcifying fluid. With the 3 mM Ca calcifying fluid the mean reduction in area of the body of the lesion was 20 per cent, brought about by a mean increase in orientated mineral of 17%. When the 1 mM Ca calcifying fluid was employed, remineralization occured throughout the entire depth of the lesion. Under these conditions, a mean reduction of 69 per cent in area of the body of the lesion occurred with a mean increase of 40% in orientated mineral. Scanning electron microscopy showed that crystal diameters for sound enamel were in the range 35–40 nm. In the body of the lesion crystal diameters were reduced and found to be in the range 10–30 nm. In lesions remineralized with the high Ca calcifying fluid crystal diameters of 50 nm were found. When the low Ca calcifying fluid was used, remineralized lesions showed crystal diameters in the range 50–150 nm with a small number having diameters of 200 nm.

Soil loss variation within a Colorado Alpine area

AbstractThe areally weighted surface erosion for Niwot Ridge, an alpine interfluve in the Colorado Front Range, is 10−1 mm/y. This may be subdivided into rates for three generalized cover types: tundra meadow, 10−2 mm/y; dry tundra, 10−1 mm/y; late‐lying snow patches, 10° mm/y. Tundra meadow (about 50 per cent of the interfluve area) yields about 5 per cent of the eroded material; dry tundra (35 per cent of the area) contributes slightly less than 50 per cent of the eroded material; while nivation hollows occupied by late‐lying snow patches occupy only about 3 per cent of the area they contribute 50 per cent of the eroded material. The bulk of the surficial erosion is accomplished between June and September, primarily by rainsplash, except where snowmelt is important. The overall estimated surface lowering rate presented here is substantially higher than those reported previously.

Thermal stability of reconstituted collagen fibrils. Shrinkage characteristics upon in vitro maturation

Thermal stability measured as area shrinkage without tension during heating was determined for membranes of collagen fibrils reconstituted from solutions of highly purified rat skin collagen. Shrinkage in per cent of area at 25 °C and shrinkage temperature were quantitated in a standardized way and determined as a function of in vitro maturation time from 11 to 104 days after aggregation for the collagen membranes. Similar to reports on intact rat skin, shrinkage temperature remained constant and shrinkage per cent declined with a rate decreasing with time during maturation. Solubility in water at 80 °C for 2 hours was 95–96% and remained unchanged for the maturation time (about 2 months) studied. The decreased shrinkage reflecting a lower degree of collapse is ascribed to an increasing thermal stability of the membranes during maturation. Development of heat-stable bonds in the reconstituted collagen fibrils is taken to be amenable to this increased stability. Similarity in changes of shrinkage characteristics during in vivo and in vitro maturation indicates that maturation changes in reconstituted collagen fibrils reflect those occurring in intact collagen during in vivo aging.

The geological significance of Early Precambrian rocks

The measured age of meteorites and some lunar rocks is approximately 4600 Ma. There is strong, indirect evidence from a comparison of terrestrial lead isotope abundances with meteoritic ones that the Earth is also of this age. By about 3700–3800 Ma. ago (and possibly well before this) surface cooling and geochemical differentiation had progressed sufficiently to produce continental crust of unknown extent and thickness, but comprising a wide variety of igneous, sedimentary and metamorphic rocks, mostly characteristic of the well-known Archaean bimodal ‘granite-greenstone’ association. The best preserved and documented crustal segment of this age occurs in the Godthaab-Isua region of West Greenland. Rocks in the age range 2500-2900 Ma. occur on all continents. It is possible that about 50 per cent in area of the present continental crust already existed at that time, with a thickness closely comparable with modern continental crust. In the present paper, a strictly uniformitarian approach to the past 3800 Ma. of Earth history is favoured on the basis of geological, geochemical and isotopic evidence. It is postulated that global mobility along the lines inherent in the new global tectonics has produced irreversible chemical differentiation of part of the Earth's upper mantle, and led to gradual formation of the continental, sialic crust over the whole of geological time.

Destruction of Vegetation- and Ground-Cover Owing to Man Influences on the Southern Exposure of the Belanské Tatry Mts

The heaviest impairment of forest stands and dwarf-pine ones in the West Carpathians (where the Belanské Tatry Mts also are included) was made owing to man action during the Walachian colonization. Forests are damaged with the exception of preserved areas practically up to this time. Besides a decrease of the timber-line, scenes of fire in dwarf-pine stands and other ways of the impairment of the vegetative cover an intensive ground destruction has appeared, too. This contribution deals with a history of man influences evolution on the southern side of the Belanské Tatry Mts, where derogatory anthropogemic hits on the vegetative- and ground cover have presented the most strikingly. In the present, all ground destruction processes as soil erosion, slope moves and cryopedological processes (creating by means of frost action on the ground) are accelerated owing to an unpropitious action of man in this range of mountains. Altogether 18.5 per cent of area is immediately damaged by various forms of the ground destruction above the empirical (contemporary) timber-line mostly from 1,500 to 2,100 metres above sea level in the subalpine and alpine zone of the central part of the Belanské Tatry Mts (area of 1,024 ha). But an individual areal proportion of the anthropogennic ground destruction forms is not possible to express in numbers exactly. Still a representation of the anthropogennic ground destruction forms, but especially an injury of the vegetative cover, is more manifest (after the author's recognition in the field) in the southern side of the Belanské Tatry Mts in comparison with their other parts. It is called forth above all by it that the southern side of the Belanské Tatry Mts implies in comparison with northern one only imperceptible signs of the glacial action. Consequently smooth relief forms have been created here. Their slopes with excellent pasture conditions have always attracted an attention of man. A pasturage had influenced the study area mostly, because it has come down there already from the 13th century. There were especially flocks of sheep and black cattle kept out at a grass in the subalpine and alpine zone. A number of sheep emounted to 1,670 during its reduced capacity in 1954 when the pasturage was stoped by the Tatra National Park Administration. In this year an area of the grazing-land amounted to about 650 ha. There were 1,800 ha of area owing to an irregular pasture endangered in the Belanské Tatry Mts together. An average upper limit-line of originally employed natural grazing-lands had reached up to 1,660 metres above sea level, a maximum one to 2,038 metres, a. s. l. on the southern slopes of the Belanské Tatry Mts. Shepherds lowered an original timber-line of 300 metres sporadically during a deforestation of that area. In tho present the timber-line extends on the average about 1,400 metres a. s. l., continuos dwarf-pine stands only 1,717 metres a. s. l. there. Besides a destruction of the vegetation also a direct ground destruction was found as a result of the hoof-stamp of grazing sheep and cattle. The same damage is made by chamois but its extent is comparatively smaller. The pasturage has influenced a confusion of plant-associations, too. The most marked plant-associations are (nearly former chalets, in the places of the intensive pasture and a concentration of cattle) the following: Rumicetum obtusifolii, Alchemilletum pastoralis, Urticetum dioicae, Deschampsietum caespitosae, Calamagrostidetum villosae and Nardetum strictae. There are the infiltrate conditions deteriorated (as much as seven times worse in comparison with natural plant-associations under a dwarf-pine) in these associations. Further unpropitious influences of man had appeared owing to his mining action in the Belanské Tatry Mts. There was mined above all copper, iron, silver and gold in dispersed mines from the 15th to 18th century. A lot of topical place-names of peaks, mountain ridges, slopes and valleys are an evidence of the heavy influence of both the pasturage and the mining. Destruction of the dwarf-pine stands was connected also with getting of raw-material for the dwarf-pine oil production. We can find recent forms of the ground destruction (when no pasturage and miming exist in the Belanské Tatry Mts) especially at both the tourist paths and the building site of tourist facilities (e. g. ski-ing hoists) where an area of the denuded surface is enlarged. On the bare soil the ground ice (especially the needle-ice, so called the pipkrake) is created during days with regelation processes. The pipkrake along with wind erosion and surface ren-off cause a number of the ground destruction forms in those high mountain areas.

A Theory on the Mechanics of Axisymmetric Extrusion through Conical Dies

For axisymmetric extrusion through conical dies, an admissible velocity field without discontinuities was obtained by superposition of basic flow patterns. Based on this velocity field, the upper bound to the average forming pressure and the detailed mechanics were calculated for the extrusion of a rod with a semi-cone angle of 45° and a reduction of 75 per cent in area. Three different friction conditions along the die were considered and their influence on the deformation characteristics was discussed. Flow lines, velocity components, grid distortion, strain-rate components, effective strain rate, effective strain, and stress components were plotted. A comparison of the present results with those obtained experimentally (visioplasticity) shows good agreement.

Soil-plant relationships of two steppe desert shrubs

Greasewood and hopsage shrubs growing together on the same ground accumulated large amounts of sodium and potassium respectively. The decay of accumulated leaf litter beneath the canopy spread of these shrubs has altered the soil chemistry over about 20 per cent of the ground area. About 14 per cent of the surface soil area is being supplied with sodium and about 7 per cent of the area is being supplied with potassium. At the present time minerals are being supplied at a rate faster than they can be leached away. The location od shrubs needs to be considered when collecting soil samples for studies of effects of certain kinds of desert shrubs on chemical and physical properties of soil.

Names on the Ocean Bottom, or Some Observations on the Invisible Landscape

AMONG THE NEARLY WIDE-OPEN SPACES where the place-namer has been able to exeroise his art increasingly in recent decades are, first, the universe, which, having bowed to Miss Fuller (in spite of Carlyle) and the march of science, the place-namer has accepted as his oyster; second, more specifically, the moon, both fore and aft, now the subject of frequent maps in the daily newspapers; third, the subcontinent of Antarctica, upon whose white surface, figuratively, hundreds of new names have appeared as a result of the extensive explorations following World War II; and fourth, the ocean bottom, where scientists are daily adding new names. Although the oceans cover 71 per cent of the surface of the earth (about 140,000,000 square miles), the number of names labeling features of the land forming their bottom is extremely small. Accurate maps exist for only about one per cent of this area. Indeed, place names in the abyssal deeps, which occupy, at a guess, 90 per cent of the ocean area, were, until very recently, almost nonexistent. It is ironic to note, says one authority, that names for the constellations and signs of the zodiac, stretching through the depths of space, date from perhaps 3,000 B.C., while names still do not exist for countless sub-oceanio features comparatively so nea·rus on our own planet. Moreover, much more is known about the surface of the moon, many of whose features have long been named, than is known about many parts of the nearby ocean depths. Submarine place names on general and popular maps, depicting oceans and continents as apart from navigational charts, were almost unheard of a decade or so ago, and are not common now. Among map publications in the English language, the only area

STRUCTURE AND METAMORPHISM OF THE KEENE-BRATTLE-BORO AREA, NEW HAMPSHIRE-VERMONT

Metamorphosed sedimentary and volcanic rocks, ranging in age from middle Ordovician (?) to lower Devonian, occupy about 55 per cent of the Keene-Brattleboro area of southwestern New Hampshire and southeastern Vermont. Rocks of the low-grade zone of metamorphism are present in a north-south band near the western edge of the area; rocks of the middle-grade zone occur on either side of the low-grade zone; and rocks of the high-grade zone occupy the central and eastern parts of the area. The lithology of the stratified rocks is similar to that farther north. The Bernardston formation of north-central Massachusetts is correlated with the Littleton formation. Foliated igneous rocks of middle Devonian (?) and late Devonian (?) age occupy about 45 per cent of the area. These include three plutons of the Oliverian magma series and five members of the New Hampshire magma series. The stratified rocks were severely folded, broken by a major thrust fault, and metamorphosed during the late Devonian (Acadian) orogeny. The resulting structural features in this area, trend almost north. The Bronson Hill anticline occupies most of the area. Three elongate domes, each with a plutonic core of the Oliverian magma series and a surrounding envelope of stratified rock, are present on this anticline. A pluton of Kinsman quartz monzonite occurs in a structural basin on the anticline, near the center of the area. The steeply dipping western limb of the Brattleboro syncline occupies the western one-eighth of the area. The Northey Hill thrust, a major fault of western New Hampshire, separates the Bronson Hill anticline from the Brattleboro syncline. This thrust, which cuts out the eastern limb of the Brattleboro syncline, has a stratigraphic separation of about 10,000 feet. Foliation and bedding are mutually parallel in most of the stratified rocks east of the Northey Hill thrust, whereas foliation is parallel to the axial planes of folds in most of the rocks west of the thrust. Minor folds of two ages are present west of the thrust and in a few places just east of thrust. The older minor folds are isoclinal, or nearly so, and have a well-developed axial-plane flow cleavage. The younger minor folds are more open and have an incipient to strong axial-plane slip cleavage. It is believed that the Oliverian magma series was forcefully injected as a thick composite sheet during the very early stages of the orogeny, while the enclosing rocks were essentially flat. The New Hampshire magma series was emplaced during the late stages of the orogeny. Initial movements along the Northey Hill thrust may have occurred during early stages of the orogeny, but a considerable part of the movement took place after the metamorphic intensity in the rocks along the fault had reached its maximum. The Triassic border fault, which forms the eastern border of the Triassic rocks of the Connecticut valley in Massachusetts, enters the area 1 mile east of the Connecticut River and trends northeasterly to the vicinity of Keene, where it apparently ends. The maximum stratigraphic displacement along the fault is about 15,000 feet. Numerous small high-angle normal faults are present. In three localities, graben, in which the roof of one of the plutons of the Oliverian magma series is preserved, form very striking structural features. The normal faults which bound the graben have a maximum stratigraphic separation of 3000 to 4000 feet. The age of the faulting associated with the graben, and also much of the normal faulting of western New Hampshire, is believed to be Triassic. Fluorite deposits of the Keene-Brattleboro area are also believed to be Triassic.

Recent Glacier Recession in Glacier National Park, Montana

The magnitude of recent glacier recession in this area has been brought to light by means of detailed mapping of several of the larger glaciers and examination of many-others. Results indicate that since the beginning of the present century some of the principal glaciers have been reduced 40-75 per cent in area and more in volume. Several smaller glaciers have nearly or entirely disappeared during the same interval; and in a warm, dry summer all snow from the previous winter is dissipated from the firn areas or zones of accumulation on nearly all the glaciers.

Root Habits of Longleaf Pine and Associated Species

Longleaf pine, Pin fs palustris Miller, at one time covered an area in the south of more than 30 million acres. Today, owing to the inroads by agriculture and by other species following the cutting of the original timber, a survey in 1934 and 1935 showed that less than 80 per cent of this area is still considered longleaf pine forest land. According to this survey, about 15 million acres are in saplingand sawlog-size stands of longleaf, nearly 2.5 million acres in reproduction, and the remaining 7 million acres are clear-cut and have failed to reproduce satisfactorily. It is estimated that nearly 30 per cent of the longleaf reproduction area is stocked satisfactorily with 900 or more seedlings per acre.1 The remaining 70 per cent shows a low stocking of seedlings, ws hich is principally due to destruction by uncontrolled fire, to damage by hogs, or to a lack of seed trees. The characteristic stunted condition of the longleaf pine seedlings, which lasts 4 to 10 or more years, makes them especially susceptible to fire and hogs as well as to annual defoliation by the brown-spot needle disease (Septoria acicola [Thiim.] Sacc.). When the pine seedlings emerge from the stunted condition, they begin rapid growth in height, and the danger of disease is considerably reduced. Since over 50 per cent of the extremely large clear-cut area (7 million acres), that must be reforested before becoming again productive, averages 3 or more seed trees per acre, while the remaining half has only 1 or 2 seed trees per acre, if the factors of destruction can be controlled, satisfactory natural reproduction should be possible on three-fourths of it. A recent study (1938), in which the writer found that the removal of grass from the vicinity of 12-year-old longleaf pine seedlings stimulated their growth to a marked degree, suggests that the roots of the grasses compete with those of the pine seedlings and that by the removal of the grasses this competition may be eliminated, permitting the pines to develop more rapidly. This present study, therefore, was designed to determine the characteristics of the roots of the pine seedlings and of other species growing in the same area, and also to determine what relationship exists between the roots of the pine seedlings and those of the other species commonly associated with them. 1 The estimates were supplied by the Survey Division of the Southern Forest Experiment Station.

Mechanical Aids for Distribution Work in Detroit, Michigan

The City of Detroit has gone through a remarkable growth in the last ten years. The United States census of 1910 reported a population of 465,766. The population reported in 1920, for the City proper was 993,739. Adding the suburbs supplied by the Detroit Water Works, the population is brought to a figure considerably over a million. In 1916 a large annexation was voted upon and passed, amounting to an increase of 63 per cent in area. This large annexation called for a large distribution extension. Prior to 1915 an addition of 40 to 45 miles of water pipe in the distribution system was considered a good year's work. The following is the amount of pipe laid by years, from 1915 to date: