• Sherri L. Johnson - Principal Investigator
  US Forest Service ;Pacific NW Research Station ;3200 SW Jefferson Way, Corvallis, OR, 97331, USA
  Phone: 541-758-7771
  Email: sherri.johnson2@usda.gov, sherri.johnson@oregonstate.edu
  URL: https://www.fs.fed.us/research/people/profile.php?alias=sherrijohnson
• Julia A. Jones - Principal Investigator
  Oregon State University;Department of Geosciences; Wilkinson Hall 104, Corvallis, OR, 97331-5506, USA
  Phone: (541) 737-1224
  Email: Julia.Jones@oregonstate.edu, geojulia@comcast.net
  URL: http://ceoas.oregonstate.edu/profile/jones/
  ORCID: http://orcid.org/0000-0001-9429-8925
• Matthew G Betts - Principal Investigator
  Department of Forest Ecosystems and Society; 201E Richardson Hall; College of Forestry; Oregon State University, Corvallis, OR, 97331
  Phone: (541) 737-3841
  Email: matt.betts@oregonstate.edu
  URL: http://www.fsl.orst.edu/flel/index.htm
• Michael P. Nelson - Principal Investigator
  Department of Forest Ecosystems and Society; 201K Richarson Hall; College of Forestry; Oregon State University, Corvallis, OR, 97331
  Phone: 541-737-9221
  Email: mpnelson@oregonstate.edu
  URL: http://www.michaelpnelson.com
  ORCID: http://orcid.org/0000-0001-6917-4752
• David Bell - Principal Investigator
  Email: david.bell@usda.gov, david.bell@oregonstate.edu
  URL: https://lemma.forestry.oregonstate.edu/about/david-bell

• The H.J. Andrews Experimental Forest is a living laboratory that provides unparalleled opportunities for the study of forest and stream ecosystems in the central Cascade Range of Oregon. Since 1980, as a part of the National Science Foundation Long Term Ecological Research (NSF-LTER) program, the Andrews Experimental Forest has become a leader in the analysis of forest and stream ecosystem dynamics.
• Long-term field experiments and measurement programs have focused on climate dynamics, streamflow, water quality, and vegetation succession. Currently researchers are working to develop concepts and tools needed to predict effects of natural disturbance, land use, and climate change on ecosystem structure, function, and species composition.
• The Andrews Experimental Forest is administered cooperatively by the USDA Forest Service Pacific Northwest Research Station, Oregon State University and the Willamette National Forest. Funding for the research program comes from the National Science Foundation (NSF), US Forest Service Pacific Northwest Research Station, Oregon State University, and other sources.

Data were provided by the HJ Andrews Experimental Forest research program, funded by the National Science Foundation's Long-Term Ecological Research Program (DEB 2025755), US Forest Service Pacific Northwest Research Station, and Oregon State University. National Science Foundation: DEB1440409

• Long-Term Ecological Research
  The Andrews Forest is situated in the western Cascade Range of Oregon, and covers the entire 15,800-acre (6400-ha) drainage basin of Lookout Creek. Elevation ranges from 1350 to 5340 feet (410 to 1630 m). Broadly representative of the rugged mountainous landscape of the Pacific Northwest, the Andrews Forest contains excellent examples of the region's conifer forests and associated wildlife and stream ecosystems. These forests are among the tallest and most productive in the world, with tree heights of often greater than 250 ft (75 m). Streams are steep, cold and clean, providing habitat for numerous aquatic organisms.

• Sapflow
• Transpiration is measured at 30-second intervals and averaged every 20 minutes with constant heat sapflow sensors (Granier 1996) installed in 5 to 7 trees of each species/age-class, with at least three sensors per tree (more details on sensor positions is provided below). These trees were cored with an increment borer to determine sapwood depth. It is critical to note that the power requirements for sapflow measurements preclude a good random sample of trees throughout the watersheds. Instead, the sample trees lie in a cluster near the base of the watersheds and thus the data to date are unavoidably biased due to the sampling design. In WS1 trees lie along two "transects", one each of alder and Doug-fir, just above the weir. These run normal to the stream through a pocket of each vegetation type up the southern (north facing) slope. The transects are 50m long, and 7 trees were selected along the transect at roughly equal intervals. Due to limitations of power and equipment, we measured red alder only in 1999; in subsequent years we estimated sap flux in red alder based on relationships between red alder and Douglas-fir in 1999. We began measurements in WS2 in 2000. In WS2 we selected 5 Douglas-fir and 3 western hemlock (all overstory trees) in a transect on the N side of the stream about 50m below the weir.
• The maximum potential effect on sap flow estimates due to background temperature fluctuations (insert citation) was evaluated and found to be detectable yet minimal. Based on measurements taken of background temperature fluctuations during six warm, sunny days in July, we found that sap flow may be underestimated by 3.7+/-0.5% and 0.2+/-0.5% per day in young and old Douglas-fir respectively, and overestimated by 6.0+/-1.1% in hemlock during the month of July.
• Sap flux density for each individual sensor over each 20 minute period was determined from temperature differentials using equations in Granier (1987). These measurements were scaled to the whole-tree and species level generally using the procedures described in Phillips et al. 2002. In red alder we installed sensors at three depths (0-20 cm, 20-40 cm and 40-60 cm) in five trees and we determined the average gradient in sapflow from the outer to inner sapwood. Using this gradient we "scaled" outer flux measurements in the other trees to a whole tree basis, and then divided by the total sapwood area of that tree to come up with the average sap flux density. In Douglas-fir and western hemlock we installed most sensors at a depth of 0-20 cm, but we also installed sensors at 20-40 cm in 4 of the old-growth trees. We combined information from these four trees with sap flux measurements from Douglas-fir at Wind River to analyze how radial gradients in sap flow are affected by site, tree age and seasonal variation. From this analysis we developed a predictive relationship to estimate radial variation based on measurements in the outer 2 cm of the sapwood, and we then used these relationships to estimate whole-tree sap flow over 20 min intervals for each measurement tree. For hemlock we took advantage of radial measurements of sapflow by F.R. Meinzer at Wind River. Meinzer's data show that sapflow declines linearly from the outer edge of sapwood to the sapwood/heartwood boundary. We used this relationship to estimate whole tree sapflow from measurements in the outer 2 cm in hemlock. We found no difference in whole-tree sap flux density for any species or size/age class as a function of distance from the stream, so we averaged the data (for each time increment) over the total number of sample trees to develop the mean sapflux density for measurement period for each species/size class. We multiplied this value for red alder by the sapwood basal area of hardwoods in WS1 to estimate hardwood transpiration. We multiplied this value by the sapwood basal area of all conifers (which is >95% Douglas-fir) to estimate conifer transpiration in WS1. We multiplied the valued for old hemlock and Douglas-fir, respectively, by the sapwood basal areas of these species in WS2 (which account for >95% of the sapwood basal area of all trees in this watershed) to estimate transpiration in WS2. The sap fluxes over 20 min intervals were summed to obtain daily sap fluxes.
• 2001-2002: "Select 7 Douglas-fir and 7 red alder in a ~70 m transect perpendicular to the stream at the base of WS1. Select 5 Douglas-fir and 3 western hemlock in a ~70 m transect perpendicular to the stream at the base of WS2.
• For replacement series plots, select 8 trees (4 Douglas-fir and 4 red alder in mixed plots) in each of 8 plots (4 at each site) for a total of 64 trees (and 64 sensors)." Install 2 sensors per tree in WS1 in the outer xylem at approximately 1 m above the ground at a depth of 0-20 mm. Install 1 sensor per tree in WS1 in the inner xylem at approximately 1 m above the ground at a depth of 20-40 mm. Install up to 3 sensors per tree in WS2 in the outer xylem at approximately 5 m above the ground at a depth of 0-20 mm. Install up to 2 sensor per tree in WS2 in the inner xylem at approximately 5 m above the ground at a depth of 20-40 mm. For replacement series plots, install 1 sensor per tree at approximately 0.5 m above the ground (below the first live branch) to a depth of 0-20 mm.
• Follow methods for calculating sap flux from A. Granier (1987). For radial profiles, use the methods of N. Phillips (2002) in Douglas-fir. Use radial profile from 4 red alders in WS1 for alder. Assume all red alders are 100% sapwood (no heartwood).
• Measure basal areas on every tree over 1 cm diameter in transects perpendicular to the stream on both sides of the stream in WS1 and WS2. In WS1, transects composed of five 10x10 meter plots alternating sides of stream every 200 meters for a total of 7 transects. In WS2, transects composed of 3 20x20 meter plots on both sides of the main stream every 200 meters for a total of 3 transects. Measure sapwood depth, bark depth, and heights on 5 of each species in each plot. Basal areas were measured using diameter tapes at breast height. Sapwood depths and bark depths were measured at breast height with and increment borer and by visually inspecting the oore for lenth of "wet" xylem. Heights were measured with a laser altimeter. Additional measurements were taken in each plot of slope aspect and angle, using a compass and laser altimeter, respectively. Species too small to be cored (~less than 5 cm DBH) were assumed to be 100% sapwood at breast height.
• In many cases, individual sensors were not functional over periods of several days. Because of the small sample sizes, dropping these individuals from the overall mean could result in large artifacts in the time-series data. Therefore, we interpolated to fill "missing" data based on relationships among the sensors when all functioned properly.
• Vegetation surveys were conducted in 1999 in WS1 and 2000 in WS2 to quantify the species composition and basal sapwood area of all woody vegetation >1 cm diameter in the riparian zones (arbitrarily defined as 100 m swath centered on the stream bed) of the two watersheds. In each WS, we established transects normal to the stream every 200 m upstream from the weir. The transects alternated from one side of the stream to the other. Along each transect we established contiguous square plots - in WS1 there were five 10m-square plots and in WS2 there were three 20m-square plots on each transect (plot dimensions were determined for the horizontal plane - i.e., they were slope-corrected). Within each plot we measured the diameter and species of every tree greater than 1 cm diameter as well as height and sapwood depth of 5 trees of each species in the plot, systematically selected to represent the size distribution in that plot. From the sample of trees used for measurements of height and sapwood depth, we developed species-specific regression equations to predict sapwood area from DBH outside the bark. Cover (by percent area) estimates of shrubs and herbaceous species were made using the line intercept technique from a diagonal transect running from the SW to the NE corners of the plots, with species identified when possible.
• Integrated volumetric water content of the top 0.30 m of the soil was measured hourly using 4 water content reflectometers (Campbell Scientific, Logan, UT) distributed evenly within the sap flow transect of WS2.
• Time domain reflectometry measurements (Tektronix 1502C, Gray and Spies 1995) integrated over the top 0.45 m were taken approximately once every 2 weeks at 16 locations throughout the sap flow transects of WS1 and WS2.

• Follow methods for calculating sap flux from A. Granier (1987)
• Methodology Instrumentation: constant heat sapflow sensors Methodology Algorithm/Statistics:,,, name, sapflow
• Description, converts millivolt sapflow sensor output to sapflux per unit sapwood area (millimeters per second) by:
• K=(dT(m)-dT)/(dt)
• u=0.119 * K^1.231
• F=u*S
• dT(m) and dT are the temperature differences between the two probes
• S = the cross sectional area of the sapwood at the location of the heated probe (in square meters)
• F = the total sap flow in millimeters per second

• Sampling frequency: annual

• Select 7 Douglas-fir and 7 red alder in a ~70 m transect perpendicular to the stream at the base of WS1. Select 5 Douglas-fir and 3 western hemlock in a ~70 m transect perpendicular to the stream at the base of WS2. Install 2 sensors per tree in WS1 in the outer xylem at approximately 1 m above the ground at a depth of 0-20 mm. Install 1 sensor per tree in WS1 in the inner xylem at approximately 1 m above the ground at a depth of 20-40 mm. Install up to 3 sensors per tree in WS2 in the outer xylem at approximately 5 m above the ground at a depth of 0-20 mm. Install up to 2 sensor per tree in WS2 in the inner xylem at approximately 5 m above the ground at a depth of 20-40 mm
• For replacement series plots, select 8 trees (4 Douglas-fir and 4 red alder in mixed plots) in each of 8 plots (4 at each site) for a total of 64 trees (and 64 sensors).

• Andrews Watershed 1
  W -122.25683100, E -122.23581300, N 44.20851700, S 44.19901700
  Altitude: 1027 to 1027 meter
• Andrews Watershed 2
  W -122.24397600, E -122.22974100, N 44.21338500, S 44.20617800
  Altitude: 1079 to 1079 meter
• UNIT L405
  W -122.19824144, E -122.19122322, N 44.25702372, S 44.25284439
  Altitude: 879 to 879 meter
• UNIT L404
  W -122.19891567, E -122.19212205, N 44.25007353, S 44.24364806
  Altitude: 812 to 812 meter

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