Seismic retrofit imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41 and the New Zealand Society for Earthquake Engineering (NZSEE)'s guidelines. These codes must be regularly updated; the 1994 Northridge earthquake brought to light the brittleness of welded steel frames, for example. The retrofit techniques outlined here are also applicable for other natural hazards such as tropical cyclones, tornadoes, and severe winds from thunderstorms. Whilst current practice of seismic retrofitting is predominantly concerned with structural improvements to reduce the seismic hazard
Natural beech wood global climate changes can also have a profound effect on what kind of natural woodland can grow and survive in a specific area. European beech is usually more susceptible to climatic changes than soil-composition and the current global climate change are found to affect the geographical distribution of natural beech wood habitats. The term "Natural" is often confusingly used as a synonym for "Primeval". While primeval woodlands that still exists, are indeed natural, natural woodlands does not have to be primeval per se. Secondary or re-established woodlands can also be natural; it is just a matter of whether a given