The Trask River Watershed Study in the northern Oregon Coast Range was designed to examine physical, chemical, and biological effects of contemporary forest management practices on aquatic ecosystems. We measured stream temperature for 11 summers in 15 small watersheds, eight of which were harvested in 2012. Three riparian buffer treatments, which varied by landowner, were implemented. Using half‐hourly data, we characterized summer water temperature distributions with five percentiles: 5th, 25th, 50th, 75th, and 95th. Each percentile was analysed as a separate response variable using a linear mixed model. After harvest, streams without overstory buffer requirements showed shifts in all the percentiles of the temperature distribution; the largest increase (3.6°C) occurred at the 95th percentile. Sites with narrow riparian buffers showed little to no change. We also calculated changes in duration of thermal exposure above 15°C and 16°C for two species of native stream amphibians; these temperatures occurred 4.7% and 1.3% of the time postharvest in the sites clearcut with no buffer. Analysis of distributions of summer temperatures preharvest and postharvest enabled us to more fully characterize site‐to‐site variability and responses to forest management.

中文翻译：

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俄勒冈州沿海地区Trask河流域上游的森林采伐后，夏季溪流温度变化

俄勒冈北部海岸山脉的特拉斯克河分水岭研究旨在研究当代森林管理实践对水生生态系统的物理，化学和生物影响。我们在15个小流域中测量了11个夏季的溪流温度，其中有8个是在2012年收获的。实施了三种河岸缓冲措施，因地主而异。使用半小时的数据，我们用5个百分位数来表征夏季水温分布：第5、25、50、75和95％。使用线性混合模型将每个百分位作为独立的响应变量进行分析。收获后，没有多余缓冲要求的溪流在温度分布的所有百分位数中均发生了变化。最大的上升幅度（3.6°C）出现在第95个百分点。河岸缓冲带较窄的部位几乎没有变化。我们还计算了两种自然流两栖动物在15°C和16°C以上的热暴露持续时间的变化。在没有缓冲的地方，这些温度分别在采伐后发生的时间的4.7％和1.3％。对夏季收获前和收获后温度分布的分析使我们能够更全面地描述站点间差异和对森林管理的响应。