Medium Moisture Research Articles

Experimental studies on burrowing ofocypode cursor(L.) (crustacea; ocypodidae), in response to sand‐moisture

The behaviour of the sand crab, Ocypode cursor (L.) was studied in response to sand‐moisture alternatives. Crabs generally “preferred”; the higher moisture alternative available. The lower (5%‐10%) and medium (10%‐15%) moisture langes caused greater response than the high (15%‐20%) moisture range. The crabs were capable of distinguishing between moisture alternatives even if they differed by 1 % moisture.

Clusteranalytische Differenzierung der Testaceenzönosen (Rhizopoda, Testacea) in Sphagnum

Summary A quantitative study of the Testacea of 189 samples of Sphagnum from 12 bog and fen sites and isolated Sphagnum swards was made. The upper and lower sections of the Sphagnum plants were analysed separately. Active and encysted individuals as well as empty shells were distinguished. Taking into account the vertical distribution, a new method is proposed to determine the minimal sample size (Gruppenminimalareal GMA) for Testacea in Sphagnum . The classification of Testacean associations was carried out by cluster analyses. An UWPG algorithm ( McCammon and Wenninger 1970) was used (Figs. 2-6, Table 2). The faunistic similarity between samples was computed as percent similarity of dominants (Renkonen number) because no satisfactory results were obtained with presence/absence data. The analysis differentiated 25 associations of Testacea, characterized by their dominants. fig. 7 gives the position of clusters in the space of the three factors humidity class, zone of Sphagnum stem and type of habitat (bog or fen). Some of the associations are restricted to single sample sites. The highest number of associations is found in Sphagnum swards of medium moisture content. Coenotic variability is too great to be explained by the variability of abiotic habitat conditions some of the associations match the types proposed by Schonborn (1963), but the total number is much higher and will increase significantly with more and different sites being surveyed with Similar methods.

Effects of Soil Moisture in the Summer and Autumn on the Contents of Nitrogen Compounds in Satsuma Mandarin Fruit

A study was made in the summer and autumn of 1976 on the effects of different soil moisture conditions on the contents of nitrogen compounds on the quality of Satsuma mandarin fruit.The following results were obtained:1) Fruit of high quality was obtained from trees grown under medium moisture (pF 2.0-2.5) in August and under low moisture (pF 3.0-3.5) in September. The contents of soluble solids in the juice of the fruit, the water content of the pulp and weight of the fruit were affected more by low moisture in September than they were in August.2) The proportion of alcohol insoluble solids in the pulp decreased under reduced soil moisture. This suggests that hydrolysis of polysaccharides may occur and that this produces the high sugar content in the juice when there is low moisture.3) Contents of the total and soluble nitrogen compounds in the peel and in the pulp, as measured on Oct. 4, showed greater increases under low moisture given during August and under medium moisture given during September than they did under other soil moisture conditions. Contents of the total, soluble and insoluble nitrogen compounds in the peel as measured on Dec. 4, were higher under the low moisture regime given in August than they were under the medium moisture regime for the same period.4) The contents (mg per 100 ml juice) of proline, arginine, asparagine, aspartic acid, serine and γ-amino-butyric acid increased more under low moisture than under medium moisture during August and September. High proline and arginine contents (percent based on the dry weight of juice) and a low alanine content were observed under low moisture. Contents of asparagine and aspartic acid, measured on Oct. 4, were higher under the low moisture than under the medium moisture regime given in August. The metabolism of amino acids in mandarin fruit appeared to be altered by the condition of soil moisture during August and September.

Anorganisch‐katalytische Umsetzungen von Cyanamid und dessen Metaboliten in Quarzsand II. Cyanamidabbau unter dem Einfluß von Metalloxiden und Temperatur

Inorganic catalytical breakdown of cyanamide and its metabolites in quartz sand II. Cyanamide breakdown as influenced by metal oxides and temperatureThe inorganically catalysed breakdown of cyanamide with addition of water in presence of metal oxides was studied in quartz sand. Cyanamide breakdown and the formation of metabolites was investigated in relation to the kind and quantity of metal oxides as well as temperature. The oxides or hydroxides of Mn, Cu, Zu, Ni, Co influenced the rate of cyanamide breakdown very differently. Decreasing the quantity of oxides (amorphous Fe(III) – hydroxide, ochre, rust) from 0.5 to 0.1 g or 0.05g/100g of quartz sand retarded cyanamide breakdown in an oxide specific formation of urea and dicyanamide. The influence of temperature (5 and 18°C) on the breakdown was not so great as that of moisture (5% and 150% of the water capacity). A low temperature (5°C) and high moisture regime (150% of the water capacity) retarded cyanamide breakdown considerably almost completely stopping it. The type and concentration of the metal oxide (iron oxide) as well as the moisture and temperature of the reaction medium are very important in the inorganically catalysed cyanamide and water reaction leading to the formation of urea or dicyanamide.

An automatic assembly for investigating the relaxation properties of polymers over a wide range of temperatures and medium moisture contents

An automatic assembly for investigating the relaxation properties of polymers over a wide range of temperatures and medium moisture contents

A New Processing System for Maximizing Macadamia Nut Kernel Recovery

ABSTRACT RESULTS obtained from the experiments conducted under this study indicated that the present maca-damia nut processing can be improved significantly, An increase of kernel recovery by as much as half of the present recovery can be realized if the following changes can be implemented: 1 installing short duration compression cracking; 2 maintaining macadamia nuts at medium moisture for cracking; and 3 introducing brine separation. In addition to better recovery, energy cost can be ex-pected to be reduced. Most of all, the time needed to process nuts will be greatly reduced because of the elim-ination of drying inshell nuts at low moisture range. Processing time from inhusk nuts to salable kernels can be completed in two days. All drying will be done at night. Cash flow will improve. Factory space will also be re-duced due to drastic reduction of separation labor and storage space.

The Release of Nitrogen from Sulfur‐coated Urea as Affected by Soil Moisture, Coating Weight, and Method of Placement

AbstractInformation on the release of N from sulfur‐coated urea (SCU) as affected by soil moisture in the aerated range is lacking. Laboratory incubation experiments were therefore conducted on two soils to study the release of N from SCU as affected by soil moisture in the aerated range, coating weight (SCU‐28 and SCU‐9), and method of placement (on one soil only).In the calcareous Princes Town soil the release of N from SCU increased with increasing moisture throughout the 9 weeks of study. In acid Talparo soil similar trends were present up to 3 weeks, but at 6 and 9 weeks maximum release of N occurred at medium moisture (soil moisture at pF 2.4) and minimum release at low moisture (soil moisture at pF 3.5).In Princes Town soil the difference in release of N from SCU‐28 and SCU‐9 remained throughout the 9 weeks. By 9 weeks SCU‐9 (heavy coat) released more N at high moisture level (soil moisture at pF 1.0) than SCU‐28 (light coat) at low moisture. In Talparo soil the effect of coating weight on the release of N at three moisture levels was considerably reduced from 6 weeks onwards.Ammonia volatilization losses were recorded only with Princes Town soil but they never exceeded 2.5% of the total N applied. The release of N from SCU was faster when the granules were mixed with the soil rather than surface applied. This difference between surface and mixed application was greater at high soil moisture levels.

秋季の土壌水分含量が温州ミカンの果実の発育と果汁の成分におよぼす影響

1. In order to clarify the effect of soil moisture on the development of Satsuma mandarin fruit from early autumn to harvest time, pot experiment was carried out with young Satsuma mandarin trees. In 1969, trees were allowed to grow under high, medium and low moisture conditions for 30 days, and in 1970 some of them were grown under low moisture conditions for 10, 20 and 30 days, after which they were grown under medium moisture conditions, and the others were kept under medium moisture conditions throughout the period.2. Total and reducing sugar contents of the leaves were increased with reduced soil moisture content.3. Fruit growth was depressed, and soluble solids content of the juice tended to be higher for trees grown under low moisture conditions for 30 days. Titratable acid content in the juice was highest for trees subjected to low moisture conditions for 30 days. Therefore, fruits of high quality were obtained from trees grown under low moisture conditions for longer periods.4. Total sugar contents (percent of fresh weight) in fruit became higher with reduced moisture content, but there were no significant differences in amounts per fruit between the treatments of differential soil moisture conditions. There were also no significant differences in amounts of acids per fruit between soil moisture conditions. Therefore, fruits of high quality on trees grown under low moisture conditions appeared to result from reduced absorption of water by the fruit.5. Between treatments, differences were negligible in amounts of sugars per fruit, but the ratio of reducing to non-reducing sugar differed between them. The proportion of reducing sugar became larger with reduced moisture content and the number of days the trees were subjected to it. Therefore, the metabolism of sugars in fruits appeared to be changed by low moisture conditions in September.

Growth of Azalea, [Rhododendron obtusum (Lindl). Planch. cv. Coral Bell] and Wax Myrtle [Myrica cerifera L.] as Affected by Capillary Watering, Media Type and Depth1

Abstract The avg wt increase of subirrigated dormant azalea tops after 75 days was 4.5g and of wax myrtle was 10.0g. The wax myrtle in a 30 cm deep perlite and peat medium produced the greatest fresh and dry wt which was twice as heavy as plants grown in a sand and bark medium. The peat, sand and soil and the peat and sand media produced the greatest new shoot number in azalea. The wax myrtle had greater shoot length in peat, sand and soil, and the per lite and peat media at 30cm depth, than in the peat and sand or the sand and coarse bark media. The azalea produced 5 shoots per plant which averaged 23cm in length, while wax myrtle produced 4 shoots with 41 cm in length. There was a decrease in soluble salt level and media pH but an increase in % media moisture with greater sampling depth from surface to bottom. Subirrigation may be beneficial for a wide variety of plants and cultural conditions since it provided a precise amount of water at all times.

Biological and chemical reduction of nitrate to nitrite in γ-irradiated soils, and factors leading to eventual loss of nitrite

Four soils, two of which were calcareous and the others of pH ~ 7.5, were treated with γ-irradiation at medium moisture. In the calcareous soils, biological reduction of nitrate to nitrite occurred after 0.5–2 Mrad, but was inhibited by 4 Mrad. However, extension to 12 Mrad gave an immediate and greater accumulation up to 107 parts/10 6 of water-extractable NO 2-N in all soils if they contained 200 parts/10 6 NO 3-N at irradiation; less nitrite appeared at lower moisture levels. Autoclaving before irradiation with 12 Mrad failed to stop nitrite formation, which almost certainly occurs by γ-radiolysis of nitrate. Slightly less nitrite accumulated immediately after irradiation of KNO 3 solution than in soil solutions, but the yield was much greater in the complete soil system. Nitrite formed in soil solutions was stable, whereas in 12 Mrad-treated soils 79 per cent was lost over 21 days: labelling with 15NO 2 showed that volatilisation and fixation to organic matter were almost equally responsible for loss of extractable nitrite, and addition of lignin or catechol increased the loss. Nitrogen dioxide and nitric oxide accounted for 18 per cent of the volatile deficit but nitrous oxide was not detected: gaseous nitrogen presumably accounted for the major loss.

Bioactivity of Systemic Insecticides in Corn: Relationship to Leafhopper Vector Control and Corn Stunt Disease Incidence12

Of seven granular systemic insecticides applied in-furrow at 1 1b per acre to corn, Zea mays L., at planting, carbofuran was the most effective for control of the leafhopper Dalbulus maidis (DeLong & Wolcott), followed in order of efficacy by aldicarb, methomyl, propoxur, phorate, disulfoton, and fenthion. Insect control was reflected in corn stunt disease incidence data which ranged from 16, 62, and 78% in carbofuran, aldicarb, and methomyl treatments, respectively, to 94-97% in the propoxur, disulfoton, phorate, and fenthion treatments, and the untreated control 77 days after planting. The efficacy of aldicarb and carbofuran applied in furrow at 0.5, 1, and 2 lb/acre at planting in a sandy loam soil at a medium moisture level was found to be rate-dependent in greenhouse tests. Carbofuran at 2 1b/acre was effective against D. maidis up to 5 weeks when leafhoppers were allowed a 2-hour feeding period on treated plants; aldicarb at this rate was effective for 3 weeks after planting. Carbofuran and aldicarb at 1 1b/acre were effective for 3 and 2 weeks, respectively, and at 0.5 1b/acre for 2 and 1 weeks, respectively. Carbofuran and disulfoton side-dressed at 1 1b/acre to one side of corn 28 days after planting were absorbed and trans located in sufficient quantities to be toxic to D. maidis between Days 2 and 4 after application when the insects were allowed to feed on the test plants for at least 8 hours. Insecticide activity was greater in leaves on the plant side above placement of the toxic ant than in leaves on the plant side opposite placement of the toxic ant. The side-dress application did not reduce the incidence of corn stunt disease compared to plants not treated with insecticide.

Factors affecting the formation of nitrite in γ-irradiated soils and its relationship with denitrifying potential

The extent to which nitrite accumulated in fifteen fresh soils following treatment with γ-radiation in the region of 0.75 Mrad was influenced by factors which are well known to affect microbial activity, and reduction of nitrate in un-irradiated soils. These factors are moisture, temperature, aggregate size, conditions of storage before use, and sterilization by autoclaving. Addition of calcium carbonate to increase the stability of nitrite in irradiated soils of lower pH did not improve its accumulation. There was good agreement between the ability of an irradiated soil to accumulate nitrite at medium moisture and its capacity when un-irradiated to biologically reduce nitrate (‘denitrifying potential’) under the ideal conditions of waterlogging and high concentrations of available organic carbon and nitrate. The findings wholly support a previous report of 15NO 3 reduction to 15NO 2 by irradiated soils, and strongly indicate that in calcareous soils treated with 0.75 Mrad, the reduction is carried out by radio-resistant enzyme systems of denitrifying organisms which can no longer proliferate.

Density and Behavior of Stomata of Pelargonium hortorum Ait. Grown Under Three Soil Moisture Regimes.1,2

Abstract Two cultivars of Pelargonium hortorum Ait. were exposed to 3 soil moisture regimes for 10 weeks at which time rubber silicone impressions were made of the abaxial leaf surface of young and old leaves. ‘Dark Red Irene’ leaves had fewer stomata per unit area and greater diffusion resistance than did ‘Princess Irene’ exposed to the same regime. Increase in soil water content promoted the differentiation of stomata in early stages of leaf development. As the leaves increased in size and matured the number of stomata per unit area became inversely related to soil moisture content as a result of increased leaf area with high soil moisture. The stomatal resistance, determined by diffusion porometer, in young leaves of both cultivars was highest for plants grown in soils with high moisture and lowest with medium moisture.

The effect of gamma‐radiation on the release of carbon dioxide from fresh soil

Abstract The release of CO2 from fresh soil at medium moisture was examined for 14 days after the application of gamma‐radiation over the range 0.025 ‐ 10 Mrad. All doses stimulated the release of CO2 compared with non‐irradiated soil, but there was no extra yield of gas between 4 and 10 Mrad. Rapid evolution occurred during irradiation and over the next 24 hours, but towards the end of incubation both irradiated and untreated soil produced CO2 at similar rates. Studies to elucidate the origin of CO2 indicated that the contribution from enzymes was predominant up to 2 Mrad, but at 10 Mrad, 45% of the gas could be formed by radiolytic decarboxylation of soil organic matter. Consequently, heavy irradiation of soil cannot stop production of CO2, and if high concentrations do interfere with the application of radiation to specific soil research investigations, the gas should be displaced or allowed to diffuse from the sample.

The effect of irrigation on the growth, cropping and nutrition of Cox’s Orange Pippin apple trees

SummaryCox’s Orange Pippin apple trees on M.II rootstock growing in grass on a coarse sandy loam of medium moisture retention were used to study growth and crop responses to irrigation from 1958 to 1966 inclusive. Treatments A, B and C consisted of 1, 2 and 3 in† of water applied at calculated soil moisture deficits of 1, 3 and 5 in respectively. The trees in Treatment D were not irrigated.Soil moisture deficits calculated from potential evaporation over-estimated measured soil moisture deficits by as much as 20%.Shoot and trunk growth were stimulated by irrigation during the first four years, but when the trees began to bear heavy crops the effects of watering on growth diminished considerably.Heavy bearing was not delayed by the vigorous growth induced by irrigation, and at full bearing crop yields were commensurate with the growth made. In three successive years of high yields the trees under Treatments A, B and C yielded 42%, 37% and 25% more respectively than the unwatered trees.Treatment A was uneconomical compared with B, and the latter afforded better cropping potentialities than Treatment C. There was no consistently positive effect of irrigation on fruit size, but a larger crop was generally carried on the irrigated trees without loss of size compared with the unwatered trees.In the eighth and ninth years of the experiment there was an abrupt depression in yield which was strongly associated with a depression in leaf Ca and Mg levels and an increase in the level of leaf K. Irrigated trees were more seriously affected than unirrigated trees. A nutritional effect of irrigation on the level of cropping was indicated but not established.

Effect of Three Soil Moisture Regimes on the Growth and Anatomy of Pelargonium bortorum1,2

Abstract ‘Dark Red Irene’ and ‘Princess Irene’ geraniums were subjected to low, medium, and high soil moisture regimes in the greenhouse for 10 weeks. A system was devised to maintain 3 moisture levels. Plant height, leaf area, and dry weight increased as soil moisture increased. Diameter of petioles and stems and thickness of leaves also increased as soil moisture increased. Number of xylem elements per unit area increased considerably in stems and petioles of plants grown in the high moisture regime, while phloem tissue was greater in plants grown in medium moisture. More vascular bundles were differentiated in leaves per unit as soil moisture decreased. ‘Princess Irene’ had fewer xylem and more phloem elements than ‘Dark Red Irene’, especially in plants grown in high soil moisture.

JUSTIFICATION OF WATER REGIME AND IRRIGATION REGULATIONS FOR AEROBIC RICE

Taking into account that rice belongs to the plants that form the fibrous root system the article defines the need to selection of varieties growing on unsaturated with water soil. Such a so-called aerobic rice variety has been obtained in the All-Russian Research Institute of Irrigated Agriculture. The results of the substantiation of an effective water regime on this variety sowings and the irrigation regulations are presented. Sowing was conducted by seeder under the soil warming up to 140С in 2013 and 2014 – April, 28 and 2015 – May, 8. For watering was used a drip irrigation system. The drip lines were laid every 0.6 m, the distance between the droppers was 0.33 m, the water supply through the dropper was 2.2 l / h. The soil of the experimental site is light chestnut, the humus content is 1.6 - 1.8%, the density of natural composition for the calculated layers of 0.4 and 0.6 m is 1.27 and 1.29 t / m3 respectively, the lowest moisture capacity is 24.9 and 23.8% of dry soil mass. Porosity indices for layers varied from 46.64 to 51.59%, solid phase density - from 2.52 to 2.72 t / m3. According to the provision of precipitation for the growing season 2013 is characterized as wet (306.9 mm), 2014 – medium dry (104.9) and 2015 – medium moisture (235.4 mm). The scheme of the two-factor experiment included three options for the water regime of the soil: A1 (control) – reducing the moisture content of the active layer (0.6 m) of the soil to 80% of minimum water capacity; A2 – according to option A1 until the end of the rice tillering phase in 0.4 m layer with following an increasing in the layer to 0.6 m; A3 – water regime according to the A2 option until the beginning of the grain wax ripeness with a decrease in the pre-irrigation moisture content to 70% of minimum water capacity. The second factor included the doses of fertilizers: B1 – to obtain a grain yield of 5 t / ha (N109P62K75); B2 - 6 t / ha (N131P74K90) and B3 – 7 t / ha (N151P90 K108). The supply of irrigation water in the amount of irrigation rates was controlled by the duration of irrigation, determined by the water flow through the droppers, as well as by the reads of the water meter installed on the experimental site. The timing of irrigation was determined by reducing the impact to the pre-irrigation level. With short duration of irrigation intervals (2-4 days) with bioclimatic and at least twice a month, as well as when sowing and ripening grain with thermostatic-weight. Operational control over soil dynamics was also provided by a calibrated moisture meter AQVATERR T - 350. The irrigation water consumption with a rice yield of 5-7 t / ha of grain according to three-year studies in the drip irrigation system varied from 4920 to 5357 m3 / ha, this is 4 - 6 less compared to existing flood irrigation technology. The research was carried out in 2013-2015 at the All-Russian Research Institute of Irrigated Agriculture.

Penapisan Genotipe Jarak Pagar (Jatropha curcas L.) untuk Toleransi terhadap Kekeringan

The selection of Jatropha curcasfor drought tolerance is one of the key points prior to growing the species extensively on marginal lands. The objective of this study was to determine drought tolerant genotypes based on morphological and physiological characters. The research consisted of two experiments. The first experiment was aimed at determining the moisture content of the media to generate drought stress. The experiment was arranged in a split-plot design with moisture content as the main plot and genotypes as sub-plot. Four level of moisture contents were tested, i.e. 22-23%, 27-28%, 32-33%, and 37-38%. The genotypes tested (9) were Dompu-1, Gunung Tambora, Bima (representing genotypes from dry areas); Aceh Besar, IP-2P, Komering (representing genotypes from wet areas); and IP-1M, Papua, Yogyakarta (representing genotypes from moderately dry areas). The result showed that 22-23% moisture content of the media was suitable for drought tolerance test in Jatropha curcas. The second experiment was screening of genotypes using the suitable media moisture content from first experiment. Twenty three genotypes were screened for drought tolerance under 22-23% media moisture content. The result show that Dompu-2, Indralaya and China were tolerant to drought; Sukabumi-1, Sukabumi-2, Pidi, Lahat, Kupang, Lampung-2, Lampung-3, Sumba, IP-2M, and IP-2A genotypes were moderately tolerant; Curup, Bogor-1, Bogor-2, Bogor-3, Pontianak, Pagar Alam, Palembang, Saweli, Jeneponto, and Medan genotypes were sensitive to drought. Plant height, leaf water content, leaf area and percentage of plant survival can be used as indicators of drought tolerance for seedling selection using a non-destructive method.Keywords: drought tolerance, genotypes, Jatropha curcas, screening

The reduction of 15N-labelled nitrate to nitrite by fresh soils following treatment with gamma radiation

Increases in nitrite which were previously observed in four soils from different series after treatment with γ-radiation, particularly over the dose range 0.5–0.8 Mrad, have been further investigated by a 15N tracer technique. It was thought that nitrate reduction to nitrite was taking place, and this mechanism was confirmed by reduction of 15NO 3 to 15NO 2 in all of the irradiated soils at medium moisture levels. However, three soils had a lower percentage of 15N tracer than expected in the nitrite pool, and it is considered that direct oxidation of unlabelled ammonium to nitrite is the most likely explanation.

Effect of Simulated and Natural Deer Browsing on Mountain Maple

This long-term study (1952-62) was made to measure the growth response of mountain maple (Acer spicatum) in Minnesota to different intensities of simulated and natural browsing by white-tailed deer (Odocoileus virginianus). For the test clumps browsed by deer, the annual growth of twigs within reach of deer (ground level to 7 feet) was measured in late October and remeasured in late April to determine the amount removed. Similar information was obtained on test clumps within two exclosures. To simulate various intensities of browsing, the annual growth was clipped 20, 40, 60, 80, and 100 percent. The degree of browsing had no apparent direct effect on the amount of growth the following season; other environmental factors were more important. Tolerance of mountain maple to browsing was high, however, since only 1 of 6 clumps had died after 100 percent of the annual growth had been clipped for 9 years. Sustained production of food within reach of deer was maintained at a level of use of about 80 percent. Since clumps are established primarily by the growth of underground stems, opportunities for management by cutting or by the application of common weed killers are excellent. Long-term herd management is impossible unless the deer population can be held at a level that permits adequate growth and reproduction of browse species in winter yarding areas. Adjusting deer numbers to the amount of food produced has been difficult because little is known about the degree of browsing important forage plants can withstand and still remain in a healthy productive condition. The objective of this study was to determine the level of use of mountain maple that will stimulate maximum browse production on a sustained yield basis. Test clumps of mountain maple were subjected to simulated and natural browsing by white-tailed deer. Mountain maple is a preferred and staple browse species over much of its range in the lake states, northeastern United States, and southern Canada west to the prairie provinces (Krefting et al. 1956:434). In Minnesota, mountain maple is one of the more palatable and nutritious deer foods. Tests by Fashingbauer and Moyle (1963) have shown that mountain maple has no serious nutrient deficiencies for deer. Mountain maple grows in clumps and frequently reaches a height of 20 feet or more and a diameter of 3 inches. Studies of the structure of clumps and their regeneration characteristics show that clumps are separate (R. K. Seemel, 1963, unpublished report, School of Forestry, University of Minnesota). New clumps are established from underground stems. Sprouts are produced from the growth of axillary buds in these stems. Some regeneration results from layering; stems of seedling origin are rare. Mountain maple has medium moisture and nutrient requirements and low heat and light requirements (Bakuzis 1959, Bakuzis and Hansen 1962). The study was made within the 6,000acre Jonvik deer yard on the Superior National Forest in Cook County, Minnesota. Forest cover is chiefly pole-size balsam fir (Abies balsamea), white spruce (Picea glauca), and white cedar (Thuja occidentalis), with scattered paper birch (Betula papyrifera), black spruce (Picea mariana),