Mapping tree density at a global scale.

The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.

Recording previous adverse drug reactions--a gap in the system.

AIMS: To measure the accuracy of recording of previous adverse drug reaction (ADR) history in patients admitted to a teaching hospital before and after an education programme. METHODS: One month survey of patients on one medical and one surgical ward, repeated after a 1 month education programme. Patients answered a questionnaire about previous ADRs and this information was compared with that in all relevant sections of their medical records and medication charts. RESULTS: Of 117 patients at baseline, 50 had a total of 81 previous ADRs. Only 75% were recorded on medication charts and 57% and 64%, respectively, in medical and nursing notes. In the post education survey of 124 patients, 56 had 105 previous ADRs, 85% were recorded on medication charts and 64% and 70% in medical and nursing records. These differences were not significant. Serious ADRs were also poorly recorded at baseline but, due to intervention by ward pharmacists, their recording on medication charts improved significantly after education. Pharmacists also significantly improved the quality of description of previous ADRs in both parts of the study. CONCLUSIONS: Previous ADR history obtainable from hospital patients is poorly recorded in medical records and an intensive education programme only produced a significant change in recording by ward pharmacists. Better strategies are needed to improve this essential aspect of history taking.