Climate Change Pressures Plant Hardiness Zones (Map Service)

Evaluating multiple signals of climate change across the conterminous United States during three 30-year periods (2010�2039, 2040�2069, 2070�2099) during this century to a baseline period (1980�2009) emphasizes potential changes for growing degree days (GDD), plant hardiness zones (PHZ), and heat zones. These indices were derived using the CCSM4 and GFDL CM3 models under the representative concentration pathways 4.5 and 8.5, respectively, and included in Matthews et al. (2018). Daily temperature was downscaled by Maurer et al. (https://doi.org/10.1029/2007EO470006) at a 1/8 degree grid scale and used to obtain growing degree days, plant hardiness zones, and heat zones. Each of these indices provides unique information about plant health related to changes in climatic conditions that influence establishment, growth, and survival. These data and the calculated changes are provided as 14 individual IMG files for each index to assist with management planning and decision making into the future. For each of the four indices the following are included: two baseline files (1980�2009), three files representing 30-year periods for the scenario CCSM4 under RCP 4.5 along with three files of changes, and three files representing 30-year periods for the scenario GFDL CM3 under RCP 8.5 along with three files of changes.�Plant hardiness zones provide a general indication of the extent of overwinter stress experienced by plants. PHZ are based on the average annual extreme minimum temperatures and have been used by horticulturists to evaluate the cold hardiness of plants. Specifically, the value used here is the absolute minimum temperature achieved for each year and reported as the 30-year mean. Because they reflect cold tolerance for many plant species, including woody ones, hardiness zones are most likely to reflect plant range limits. The zonal variations caused by warming temperatures in the future will therefore be useful to approximately delineate niche constraints of many plant species and hence their future range potential. Plant hardiness zones and subzones were delineated according to the USDA definitions, which break the geography into zones by 10 �F (5.56 �C) increments from zone 1 (-55 to -45.6 �C) to zone 13 (15.7 to 22 �C) of annual extreme minimum temperature. To define the coldest day per year, daily minimum temperatures were identified within the period July 1 to June 30, with the nominal year assigned to the first 6 months of the 12-month period.�Original data and associated metadata can be downloaded from this website:�https://www.fs.usda.gov/rds/archive/Product/RDS-2019-0001This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.

本世纪针对美国大陆地区在三个三十年时段（2010-2039、2040-2069、2070-2099）内，对气候变化的多重信号进行评估，并与基准期（1980-2009）进行对比，着重分析了潜在的生长度日（GDD）、植物耐寒区（PHZ）和高温区等指标的变化趋势。这些指数分别基于CCSM4和GFDL CM3模型，在代表浓度路径4.5和8.5下得出，并收录于Matthews等人（2018年）的研究中。每日气温数据通过Maurer等人（https://doi.org/10.1029/2007EO470006）的降尺度方法，以1/8度网格尺度进行计算，并用于得到生长度日、植物耐寒区和高温区。这些指数各自提供了关于植物健康与气候变化影响之间关系的独特信息，包括植物的生长、存活和适应能力。这些数据和计算出的变化以14个单独的IMG文件的形式提供，每个指数对应一个文件，以协助未来的管理与决策规划。对于四个指数，包括以下内容：两个基准文件（1980-2009年），三个代表CCSM4模型在RCP 4.5情景下的三十年时段文件以及相应的变化文件，以及三个代表GFDL CM3模型在RCP 8.5情景下的三十年时段文件和相应的变化文件。植物耐寒区提供了植物越冬压力范围的一般指示。PHZ基于年均极端最低温度，并被园艺学家用于评估植物的耐寒性。具体而言，此处使用的值是每年记录到的绝对最低温度，并以三十年平均值报告。由于它们反映了包括木本植物在内的许多植物种类的耐寒性，因此耐寒区最有可能反映出植物的分布范围限制。未来由于气温升高导致的区域变化将有助于大致划定许多植物种类的生态位限制及其未来分布潜力。植物耐寒区和亚区是根据美国农业部（USDA）的定义划分的，该定义通过每年极端最低温度的10°F（5.56°C）增量，将地理划分为从1区（-55至-45.6°C）到13区（15.7至22°C）的多个区域。为了定义每年的最冷一天，确定了7月1日至6月30日期间的每日最低温度，并以该12个月周期的前6个月作为名义年份。原始数据和相关的元数据可以从此网站下载：https://www.fs.usda.gov/rds/archive/Product/RDS-2019-0001。本记录来源于美国农业部企业数据清单，该清单输入到https://data.gov目录。本记录的数据资源包括以下内容：ISO-19139元数据、ArcGIS Hub数据集、ArcGIS GeoService。欲获取完整信息，请访问https://data.gov。