widespread uptake of the CMS across the UK, the current version, mounted on MS Access, is now, de facto, a national conservation management system. As its use becomes more widespread CMS plans are beginning to function as an evidence-based library of best practice for exchanging practical know-how between users. Data model of a conservation management system (CMS) A CMS is simply a recording and filing tool that aids and improves the way in which heritage green assets are managed and kept in a favourable condition. Its prime function is to keep track of the inputs, outputs and outcomes of projects to meet measurable objectives. The aim is to promote efficient and effective operations, and allow recording of the work that was done and reporting on whether or not the objective was achieved. A CMS also enables the exchange of information about methods and achievements within and between organisations. These are essential components of a CMS of any scale, whether a national park, or a village pond. Technically, a CMS is a project-based planning and recording system aimed at managing conservation features within acceptable limits of variation. A feature is any component of the environment that has to be managed e.g. a footpath or a species. A 'project' is simply a programme of work leading to an output e.g. 'construct a footpath', 'patrol an area' or 'record a species'. Projects are work plans that control specific factors that help or impede the attainment of management objectives. Each project includes a description of a process, e.g. the work to be done, when and where it is to be done and the inputs of resources required. When a project is completed, what was actually done is recorded. This is an output. The outcome of a CMS is the state of the feature at the end of the project and is measured by performance indicators. Performance indicators are quantitative or qualitative attributes of the features e.g. numbers of a species, and they are measured by special monitoring-projects in order to gauge success in reaching the management objectives. Copies of all projects with their inputs, outputs and outcomes are retained in the CMS to provide a progress- register, and an archive to support managerial continuity. In summary, the prime function of a CMS is to enable conservation managers to control the operational functions of a management plan as a feedback system or work-cycle by: identifying