2.1 Green assets
Critical Natural Assets and Basic Natural Stock are designations based on ecological interest and landscape value criteria.
The assessments of ecological interest were undertaken by the Lincolnshire Trust for Nature Conservation under contract to Lincoln City Council to assist with the preparation of the City of Lincoln Local Plan. They are largely based upon the survey work undertaken by Trust volunteers during the 1980s (which was summarised in the Trust's 1991 publication Wildlife in Lincoln) which has subsequently been updated by further information by volunteers and staff and evaluated by the Trust.
The information on habitats and species in a Lincolnshire context has largely been drawn from the Lincolnshire Trust for Nature Conservation's publication "Nature in Lincolnshire; towards a biodiversity strategy" which should be consulted for more detailed information.
The assessments of landscape value are based on surveys referred to in the City Council's Planning Policy Document "Open Space in Lincoln" which identified 'Areas of Special Landscape Value'. Again, those assessments have been reviewed as part of the Local Plan preparation process.
Information on the landscape character context refers to the Character Map of the English Countryside published in 1996 by the Countryside Commission in partnership with English Nature and English Heritage.

The sitesĀ  have been broadly classified into two categories:
•    Critical Natural Assets
•   Local Basic Natural Stock.
The site descriptions set out in the Critical Natural Assets and Bas/'c Natural Stock sections which follow have the following format:
•    Ordnance Survey grid reference location and status (statutory and non-statutory e.g. that identified by the Lincolnshire Trust for Nature Conservation)
•    Brief site description, including reasons for designation as Critical Natural Asset or Basic Natural Stock. The reasons stated cover:
*     the main habitats on the site, including where known their area as a proportion of the city and county area of the habitat;
*     any rare or endangered species recorded from the site. The criteria for inclusion have been taken directly from the Lincolnshire Trust for Nature Conservation's publication Nature in Lincolnshire : Towards a Biodiversity Strategy and include not only nationally rare or protected species but also those whose county populations are considered to be threatened due to presence as small or fragmented populations; evidence of serious decline or instability; or habitat change or other causes. Species known to be uncommon within Lincoln have also been listed;
*     other considerations which have contributed to the site's Local Plan designation. These include value as (or as part of) a linking area or "wildlife corridor" between other sites.
•    An assessment of the landscape value of the site where relevant.