Management of sessile oak (Quercus petraea (Matt.) Liebl.), a major forest species in Europe

Sessile oak (Quercus petraea (Matt.) Liebl.) is widely distributed across most of Europe particularly the hills and lower mountain ranges, so is considered “the oak of the mountains”. This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m, especially in Atlantic and sub-Mediterranean climates, and it is sensitive to low winter temperatures, early and late frosts, as well as high summer temperatures. Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech, European hornbeam, small-leaved lime and Acer spp. These form the understorey of sessile oak stands, promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches. Sessile oak is a long-lived, light-demanding and wind-firm species, owing to its taproot and heart-shaped root system. Its timber, one of the most valuable in Europe, is important for furniture-making (both solid wood and veneer), construction, barrels, railway sleepers, and is also used as fuelwood. It is one of the few major tree species in Europe that is regenerated by seed (naturally or artificially) and by stump shoots in high forest, coppice-with-standards and coppice forests. Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood, group shelterwood, irregular shelterwood, irregular high forest, coppice-with-standards and simple coppice. Young naturally regenerated stands are managed by weeding, release cutting and cleaning-respacing, keeping the stands quite dense for good natural pruning. Plantations are based on (1) 2–4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources, seed stands and seed orchards. The density of sessile oak plantations (mostly in rows, but also in clusters) is usually between 4000 and 6000 plants ha−1. Sessile oak silviculture of mature stands includes crown thinning, focusing on final crop trees (usually a maximum of 100 individuals ha−1) and targeting the production of large-diameter and high quality trees at long rotation ages (mostly over 120 years, sometimes 250–300 years). In different parts of Europe, conversion of simple coppices and coppice-with-standards to high forests is continuing. Even though management of sessile oak forests is very intensive and expensive, requiring active human intervention, the importance of this species in future European forests will increase in the context of climate change due to its high resistance to disturbance, superior drought tolerance and heat stress resistanc

The effect of a small dose of ketamine on postoperative analgesia and cytokine changes after laparoscopic cholecystectomy

Background and objectives: In this study we assesed the effect of a small dose of ketamine on the production of TNFα, IL-1β and IL-6 and the postoperative pain in patients undergoing laparoscopic cholecystectomy. Methods: Fifty patients undergoing laparoscopic cholecystectomy were randomized in two equal groups. Patients in the ketamine group after induction in anesthesia received ketamine – 025 mg/kg-1. At the same time patients from the control group received sodium chloride. Postoperatively, the pain was assessed with VAS at periods of 30 min at 1, 2, 4, 8, 18, 24 and 48 hours. TNFα, IL-1β and IL-6 were evaluated before surgery at 4, 18 and 24h after the operation. Results: Differences of mean values of TNFα and IL-1β between the two groups in the postoperative period were not significant. Mean values of IL-6 in the investigated group A were significantly lower than the mean values of IL-6 in the investigated group B after the 4th hour (p = 0.00990), after the 18th hour (p = 0.00133) and as after the 24th hour following surgery (p = 000860). the difference in pain intensityaccording to the VAS scale was also statistically significantly smaller in group A after 30 min, 1,2,8 and 12 hours after surgery. Conclusions: The addition of a small-dose of ketamine in patiens undergoing laparoscopic cholecystectomy resulted in attenuation of secretion of TNFα, IL-1β, IL-6 and reduction of postoperative pain. Key words: ketamine, postoperative pain, proinflammatory cytokines