Tongass National Forest Timber Suitability

This feature class represents the lands on the Tongass National Forest that are suitable for timber production. As part of the 2016 Forest Plan Amendment, Tetra-Tech developed a process to generate the dataset. Please refer to the "Forest Service R10-MB-756j Land and Resource Management Plan", Appendix A for detailed information on this process:https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd527907.pdf Tetra-Tech’s process followed two major steps: 1) the identification of lands that may be legally and practicably capable of timber production; and 2) from the lands that may be suited for timber production, identify lands that are suited for timber production based on the compatibility of timber production with the desired conditions and objectives for those lands. Suitable lands in the Forest Plan constitute the land base for determining vegetation management practices associated with timber production. Prior to 2018 previous suitabiliity models excluded eagle and goshawk nest buffers. Nest buffers, as well as a number of resource concern areas not specifically outlined in Appendix A, are not accounted for in this suitability analysis. Under the 2016 Forest Plan, suitability determinations vary in old growth and young growth areas. This feature class derived young growth areas by using the following selection statement on the Tongass Cover Type feature class: Stand_Origin = 'H' and Reserve_Amount 0)This SuitabilityFP16 feature class only displays whether an area is old growth or young growth and if it is suitable for timber harvest or unsuitable for timber harvest. If the user wishes to know why a particular area is unsuitable for timber harvest, the SuitableReasons feature class should be used. This SuitabilityFP16 feature class is recommended for use when reasons for unsuitability are not needed. There are far fewer features in this SuitabilityFP16 feature class, making its performance in GIS applications considerably better than the SuitableReasons feature class.This feature class is the output of the TNF Timber Suitability script located at the following path:T:\FS\Reference\GeoTool\r10_tnf\Script\Suitable\TimberSuitabilityForestWide64Bit.pySpecific geoprocessing steps to create the feature class are explicitly outlined in the script.本要素类代表通加斯国家森林（Tongass National Forest）内适宜用材生产的林地。作为2016年森林规划修正案的组成部分，Tetra-Tech公司开发了一套流程以生成本数据集。请参阅《林务局R10-MB-756j土地与资源管理规划》附录A以获取本流程的详细信息：https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd527907.pdf。 Tetra-Tech的流程包含两大核心步骤：1）识别具备合法且实际可行的用材生产能力的林地；2）在上述潜在适宜用材生产的林地中，根据用材生产与该林地既定条件和目标的兼容性，筛选出真正适宜用材生产的林地。本森林规划中的适宜林地构成了确定与用材生产相关的植被管理措施的土地基础。 2018年之前的旧适宜性模型未纳入鹰类与苍鹰巢缓冲区。本适宜性分析未考虑巢缓冲区，以及附录A中未明确列出的若干资源关注区域。根据2016年森林规划，老龄林与幼龄林区域的适宜性判定标准存在差异。 本要素类通过对通加斯覆盖类型要素类执行以下选择语句来提取幼龄林区域：Stand_Origin = 'H' 且 Reserve_Amount 0。本SuitabilityFP16要素类仅显示某区域属于老龄林还是幼龄林，以及该区域是否适宜木材采伐或不适宜木材采伐。若用户需了解某区域不适宜木材采伐的具体原因，应使用SuitableReasons要素类。当无需知晓不适宜性原因时，推荐使用本SuitabilityFP16要素类。本要素类的要素数量远少于SuitableReasons要素类，因此在GIS（地理信息系统）应用中的运行性能显著更优。 本要素类为TNF木材适宜性脚本的输出产物，该脚本的存储路径为：T:FSReferenceGeoTool 10_tnfScriptSuitableTimberSuitabilityForestWide64Bit.py。脚本中明确列出了创建本要素类的具体地理处理步骤。