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An issue of global concern is how climate change forcing is transmitted to ecosystems. Forest ecosystems in mountain landscapes may demonstrate buffering and perhaps decoupling of long‐term rates of temperature change, because vegetation, topography, and local winds (e.g., cold air pooling) influence temperature and potentially create microclimate refugia (areas which are relatively protected from climate change). We tested these ideas by comparing 45‐year regional rates of air temperature change to unique temporal and spatial air temperature records in the understory of regionally representative stable old forest at the H.J. Andrews Experimental Forest, Oregon, USA. The 45‐year seasonal patterns and rates of warming were similar throughout the forested landscape and matched regional rates observed at 88 standard meteorological stations in Oregon and Washington, indicating buffering, but not decoupling of long‐term climate change rates. Consideration of the energy balance explains these results: while shading and airflows produce spatial patterns of temperature, these processes do not counteract global increases in air temperature driven by increased downward, longwave radiation forced by increased anthropogenic greenhouse gases in the atmosphere. In some months, the 45‐year warming in the forest understory equaled or exceeded spatial differences of air temperature between the understory and the canopy or canopy openings and was comparable to temperature change over 1,000 m elevation, while in other months there has been little change. These findings have global implications because they indicate that microclimate refugia are transient, even in this forested mountain landscape. 

Abstract This study examined the 70‐year history of clearcutting of old‐growth forest and associated road construction, floods, landslides, large wood in rivers, and channel change in the 64 km²Lookout Creek watershed in western Oregon, where forestry practices began in 1950 and largely ceased by the 1980s. Responses differed among three zones with distinctive geomorphic processes within the watershed: a glacially sculpted zone, an earthflow‐dominated zone, and a debris slide and debris flow‐dominated zone. Watershed response to floods was more related to the timing of road construction and clearcuts, past geomorphic events, and forest dynamics than to flood magnitude. Even small (1–3 year) floods generated geomorphic responses in the period of initial road construction and logging (1950–1964) and during ongoing logging in the early part of a 30‐year period between large flood events (1966–1995). The floods of 1964/65, 15 years after the onset of logging, produced much larger geomorphic responses than the flood of record (1996), more than a decade after logging ceased. Geomorphic response was negligible for the third largest event on record (2011) during the last period (1997–2020), when former clearcuts were 20 to 70‐year‐old forest plantations. Watershed response in each of five distinct time periods depended on conditions created during prior periods in the three zones. Understanding of watershed response to forestry requires integrated observation of forestry practices, floods, landslide susceptibility, wood delivery and movement, and channel change on time scales that capture responses to past and ongoing management practices and geophysical and biological factors and events. 

abstract In this article marking the 40th anniversary of the US National Science Foundation's Long Term Ecological Research (LTER) Network, we describe how a long-term ecological research perspective facilitates insights into an ecosystem's response to climate change. At all 28 LTER sites, from the Arctic to Antarctica, air temperature and moisture variability have increased since 1930, with increased disturbance frequency and severity and unprecedented disturbance types. LTER research documents the responses to these changes, including altered primary production, enhanced cycling of organic and inorganic matter, and changes in populations and communities. Although some responses are shared among diverse ecosystems, most are unique, involving region-specific drivers of change, interactions among multiple climate change drivers, and interactions with other human activities. Ecosystem responses to climate change are just beginning to emerge, and as climate change accelerates, long-term ecological research is crucial to understand, mitigate, and adapt to ecosystem responses to climate change. 

Abstract Forest and freshwater ecosystems are tightly linked and together provide important ecosystem services, but climate change is affecting their species composition, structure, and function. Research at nine US Long Term Ecological Research sites reveals complex interactions and cascading effects of climate change, some of which feed back into the climate system. Air temperature has increased at all sites, and those in the Northeast have become wetter, whereas sites in the Northwest and Alaska have become slightly drier. These changes have altered streamflow and affected ecosystem processes, including primary production, carbon storage, water and nutrient cycling, and community dynamics. At some sites, the direct effects of climate change are the dominant driver altering ecosystems, whereas at other sites indirect effects or disturbances and stressors unrelated to climate change are more important. Long-term studies are critical for understanding the impacts of climate change on forest and freshwater ecosystems.