Forestry contracting in northern Scotland: a survey report

This paper reports results from a survey of forest contractingfirms (‘contractors’) in Northern Scotland, carriedout as part of a tripartite 1991–94 study of forestryin rural development in Scotland, Northern Ireland and the Republicof Ireland. Aspects of the overall study focused upon the structureand activities of the contractor sector of the Scottish forestryindustry, in par-ticular its sources of business, employmentcharacteristics, capital assets and future prospects. Resultsshow that the sector in 1992 was highly fragmented, while sub-contractingwas common.Harvesting and general contractors were heavily relianton the Forestry Commission for con-tracts, while silviculturalcontractors mostly relied on forest management companies andfarmers. During the last 12 years, employment has increasedonly in the general sector, while workers directly employedtended to live closer to the firm's address than sub-contractors.Finally, most harvesting and silvicultural firms in the aa were,at the time of survey, pessimistic as to the future survivalof their businesses     

Hydrochemical Fluxes and their Effects on Stream Acidity in Two Forested Catchments in Central Scotland

The hydrochemical fluxes and budgets have been determined fortwo forested catchments, including inputs, tree throughfalland stemflow, soil water throughflow and output streams. Themajor vegetational induced differences are the enrichment ofsodium, chloride, sulphate and particularly hydrogen by Sitkaspruce compared to Norway spruce. These increased concentrationsare primarily due to vegetation interception along with crownleaching, both of which contribute to sulphate enhancement.Soil throughflow and consequent stream chemistries reflect thesespecies effects with additional enrichment both due to geologicalweathering of base cations as well as possible desorption ormineralization processes. Norway spruce vegetation and the associatedpodzolic soils show no net stream acidification (pH 4.61) ofinputs (pH 4.65), whereas Sitka spruce on gleyed soils showconsiderable stream acidification (pH 4.02) compared with similarinputs (pH 4.50). Both streams have similar sulphate concentrations,but this important mobile anion is associated primarily withhydrogen in the Sitka spruce dominated Kelty catchment whereasat Chon it is associated with base cations as well as hydrogen.     

SUSTENTION AND MAXIMUM BENEFIT AS ELEMENTS IN FOREST POLICY

A short paper read before the British Association in Belfastin 1952 in which the main aims of sound management of a forestestate in being, and the special features of these aims froman industrial viewpoint, are unfolded for the understandingof the layman.     

The Effects of Forest Plantations on Some Lowland Soils I. A Second Sampling of Nutrient Stocks

Amounts of total and extractable major nutrients have been measuredin soils under a variety of tree plantations at three sitesin Lowland Britain. The measurements repeat a study performedat these sites 23 years previously. Comparisons are made betweentotal stocks of litter and soil nitrogen, phosphorus, potassiumand calcium under broadleaved and coniferous trees planted oncontrasted lowland soils. Accumulation is shown under some conifersbut few broadleaves except for alder, under which progressiveincreases in nitrogen are suggested. Nutrient stocks are shownto be related to growth rate. The results reported also lendsome support to the view that the effects of different treespecies on development of soil properties are less significant,when viewed over a whole rotation, than measurements made earlyin the rotation, especially in the canopy closure to first thinningperiod, would suggest.     

The Effects of Clearfelling a Sitka Spruce Stand on the Water Balance of a Peaty Gley Soil at Kershope Forest, Cumbria

From 1981 to 1985 the water balance of four 2 ha plots of aploughed and drained Sitka spruce plantation was monitored.During 1983, three plots were clearfelled and a fourth was leftstanding as a control. A ground level raingauge over-collected during snow, but otherwisecollected 3 per cent more water than standard raingauges. Annualprecipitation (1259–1688 mm) averaged 1439 mm. The forest canopy intercepted 38 per cent and transpired 12per cent of gross precipitation. Fifty per cent of gross precipitationwas evaporated while the other 50 per cent left the site asrunoff. Throughfall and stemfiow fractions of net precipitationwere 0.87 and 0.13 respectively. After clearfelling, annual runoff increased to 68 per cent ofgross precipitation. After adjustment using the before and aftercomparison in the control plot, the decrease in annual evaporativeloss resulting from clearfelling was 290 mm.     

PROCESSES OF HUMUS FORMATION AND TRANSFORMATION IN SOILS OF THE CANADIAN GREAT PLAINS

A study of the A horizons of cultivated soils from Saskatchewan, Canada showed that the organic carbon contents were in the sequence semi-arid Dark Brown soils (1.7 per cent), < Black soils (2.55–2.8 per cent), < sub-humid Dark Gray soils (4.5 per cent). The relative proportions of humic acids and the ratios of humic acid: fulvic acid increased in a similar sequence. There were accompanying increases in extinction values at 280 nm, and in levels of nonhydrolyzable nitrogen suggesting more extensive polycondensation of humic materials. These observations are discussed in terms of a working hypothesis for humus formation and transformations, that gives particular emphasis to the soil environment and to interactions between organic and inorganic components.     

Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

Switchgrass (Panicum virgatum L.), as a model herbaceous crop species for bioenergy production, is targeted to improve biomass yield and feedstock quality. Plant height is a major component contributing to biomass yield. Accordingly, the objectives of this research were to analyze phenotypic variation for biomass and plant height and the association between them and to localize associated plant height QTLs. Two lowland switchgrass mapping populations, one selfed and another hybrid population established in the field at Perkins and Stillwater, Oklahoma, were deployed in the experiment for two years post establishment. Large genetic variation existed for plant biomass and height within the two populations. Plant height was positively correlated with biomass yield in the selfed population (r = 0.39, P<0.0001) and the hybrid population (r = 0.41, P<0.0001). In the selfed population, a joint analysis across all environments revealed 10 QTLs and separate analysis for each environment, collectively revealed 39 QTLs related to plant height. In the hybrid population, the joint analysis across overall environments revealed 35 QTLs and the separate analysis for each environment revealed 38 QTLs. The findings of this research contribute new information about the genetic control for plant height and will be useful for future plant breeding and genetic improvement programs in lowland switchgrass.     

An assessment of cereal grains and other starch sources in diets for barramundi (Lates calcarifer) – implications for nutritional and functional qualities of extruded feeds

This study examined the digestibilities of whole diets and ingredients of a range of starch/cereal grains when fed to barramundi (Lates calcarifer). The ingredients included wheat, oats, sorghum, triticale, barley, among others. Twelve diets were prepared using a twin‐screw extruder to mimic modern aquafeed‐manufacturing processes. The diets were then fed to juvenile barramundi and the faeces collected using stripping methods. Significant variability in the digestible energy and starch value was seen among the test ingredients and diets. Diet starch digestibility ranged from 49.1% to 93.9%. Ingredient starch digestibility ranged from 18.0% to 96.5%. Among the different starch ingredients, a strong negative correlation between the ingredient amylopectin content and starch digestibility of that ingredient was observed. This relationship was also mirrored by a similar relationship, although not as strong, between total starch and starch digestibility. This study demonstrates that barramundi have limited ability to digest starch and that there is an effect of inclusion level on the ability of the animal to digest this nutrient. But it also demonstrates that there is a wide range of cereal sources that can be effectively used as starch sources in extruded diets for this species.     

Vaginal Neurofibroma in a Hysterectomized Poodle Dog

A 15‐year‐old, spayed, female poodle dog was presented for evaluation of a mass of tissue prolapsed from the vulva. The dog had been hysterectomized when it was 5 years old. A vaginal mass had been removed approximately 10 months before presentation. Haematological and serum biochemistry analyses demonstrated mild leucocytosis and glycaemia. A vaginal smear was predominantly made up of parabasal cells and intermediate cells with no neoplastic cells. Thoracal and abdominal radiographic findings were unremarkable. The ovaries could not be identified using abdominal ultrasonography. A midline exploratory laparotomy identified both ovaries that were surgically excised. The vaginal mass was also removed following an episiotomy procedure. Histopathological examination of the mass demonstrated that it was a neurofibroma. Both ovaries had cystic changes. Four months after the surgery, the owner reported that the dog was clinically normal. To the authors’ knowledge, this is the first reported case of a vaginal neurofibroma after an incomplete ovariohysterectomy in the dog.