National Forest Inventory GB 2022

The National Forest Inventory (NFI) woodland map covers all forest and woodland area over 0.5 hectare with a minimum of 20% canopy cover, or the potential to achieve it, and a minimum width of 20 metres. This includes areas of new planting, clearfell, windblow and restock. The woodland map excludes all 'tarmac' roads and active railways, and forest roads, rivers and powerlines where the gap in the woodland is greater than 20 meters wide. All woodland (both urban and rural), regardless of ownership, is 0.5 hectare or greater in extent, with the exception of Assumed woodland or Low density areas that can be 0.1 hectare or greater in extent. Also, in the case of woodland areas that cross the countries borders, the minimum size restriction does not apply if the overall area complies with the minimum size. Woodland less than 0.5 hectare in extent, with the expectation of the areas above, will not be described within the dataset but will be included in a separate sample survey of small woodland and tree features. The woodland map is updated on an annual basis and the changes in the woodland boundaries use the Ordnance Survey MasterMap® (OSMM) as a reference where appropriated. The changes in the canopy cover have been identified on: Sentinel 2 imagery taken during spring/summer 2022 or colour aerial orthophotographic imagery available at the time of the assessment; New planting information for the financial year 2021/2022, from grant schemes and the sub-compartment database covering the estate of Forestry England, Forestry and Land Scotland and Natural Resources Wales; Woodland areas, greater than 0.5 hectares, are classified as an interpreted forest type (IFT) from aerial photography and satellite imagery. Non-woodland areas, open areas greater than 0.5 hectare completely surrounded by woodland are described according to open area types. IFT categories are Conifer, Broadleaved, Mixed mainly conifer, Mixed mainly broadleaved, Coppice, Coppice with standards, Shrub, Young trees, Felled, Ground prep, Cloud \ shadow, Uncertain, Low density, Assumed woodland, Failed, Windblow. IOA categories are Open water, Grassland, Agricultural land, Urban, Road, River, Powerline, Quarry, Bare area, Windfarm, Other vegetation. For further information regarding the interpreted forest types (IFT) and the interpreted open areas (IOA) please see NFI description of attributes available on www.forestresearch.gov.uk国家森林调查（National Forest Inventory, NFI）林地地图覆盖所有满足以下条件的森林与林地：面积不小于0.5公顷，冠层覆盖度不低于20%或具备达到该覆盖度的潜力，且最小宽度为20米。该范围涵盖新造林区、皆伐区、风倒区及补植区域。本林地地图排除所有柏油公路、运营铁路，以及林地间隙宽度大于20米的林区道路、河流与电力线路区域。所有林地（含城市与乡村林地），除假定林地或低密度林区可放宽至0.1公顷及以上外，均需满足面积不小于0.5公顷的要求。若林地跨国家边界，只要整体面积符合最小面积标准，则不受单一区域的最小尺寸限制。除上述例外情况外，面积小于0.5公顷的林地不会被纳入本数据集，但会纳入小型林地与树木特征的独立抽样调查范畴。本林地地图每年更新一次，林地边界变更以英国地形测量局主地图集®（Ordnance Survey MasterMap®, OSMM）为适宜参考依据。冠层覆盖度变化通过以下数据源识别：2022年春夏季获取的哨兵2号（Sentinel 2）影像，或评估时点可获取的彩色航空正射影像；2021/2022财年来自各类资助计划的新造林信息，以及覆盖英格兰林业署、苏格兰林业与土地局、威尔士自然资源署辖区的小班数据库数据。面积大于0.5公顷的林地将通过航空摄影与卫星影像解译为解译森林类型（Interpreted Forest Type, IFT）。完全被林地环绕、面积大于0.5公顷的非林地开阔区域，将按照开阔区域类型进行分类标注。IFT分类项包括：针叶林、阔叶林、以针叶林为主的混交林、以阔叶林为主的混交林、矮林、带高标准木的矮林、灌丛、幼树、皆伐地、整地作业区、云/阴影、不确定区域、低密度林区、假定林地、未成林、风倒区。IOA分类项包括：开阔水域、草地、农用地、城市区域、道路、河流、电力线路、采石场、裸地、风电场、其他植被。如需了解解译森林类型（IFT）与解译开阔区域（IOA）的更多详细信息，请参见英国森林研究官网www.forestresearch.gov.uk上发布的NFI属性说明文档。