OTTER Meteorological and Canopy Chemistry Data Data Description Keywords: humidity, temperature, radiation, weather, leaf chemistry, net primary production, standing biomass, leaf area index (LAI), intercepted photosynthetically active radiation (IPAR) Parameters: Meteorological data (relative humidity, air temperature, solar radiation, precipitation) summarized hourly and monthly. Specific leaf area and leaf chemistry (total nitrogen, phosphorus, amino acids, starch, chlorophyll a and b) summarized monthly for one site and four times per year for others. Average forest canopy percent intercepted photosynthetically active radiation (IPAR). Average trees ha-1. Average basal area (m2 ha-1). Average leaf are index (LAI). Average above-ground biomass (Mg ha-1) (branch, bark, stem, foliage and total). Average above-ground net primary production (Mg ha-1 yr-1) (branch, bark, stem, foliage and total). Site locations and characteristics: Name: Site 1 "Cascade head" Location: 44 03' (N) 123 57' 30" (W) Elevation: 240 Slope (percent) : 12 Aspect (degrees): 130 Dominant Tree Species: Picea sitchensis, Tsuga heterophylla Name: Site 1A "Cascade Head Alder Stand" Location: 44 03' (N) 123 57' 30''(W) Elevation: 200 Slope: 0 Aspect: 0 Dominant Tree Species: Alnus rubra Name: Site 2 "Warings Woods Location: 44 36' (N) 123 16' (W) Elevation: 170 Slope: 13 Aspect: 160 Dominant Tree Species: Pseudotsuga Menziesii Name: Site 3 "Scio Control" Location: 44 40' 30" (N) 123 36' 40 (W) Elevation: 800 Slope: 12 Aspect: 325 Dominant Tree Species: Tsuga heterophylla, Pseudotsuga Menziesii Name: Site 3F "Scio Fertilized" Location: 44 40' 30" (N) 123 36' 40 (W) Elevation: 640 Slope: 0 Aspect: 0 Dominant Tree Species:Tsuga heterophylla, Pseudotsuga Menziesii Name: Site 4 "Santiam Pass" Location: 44 25' 20" (N) 121 50' 20 (W) Elevation: 1460 Slope: 0 Aspect: 0 Dominant Tree Species: Tsuga mertensiana Name: Site 5 "Metolius Control Location: 44 25' (N) 121 40' (W) Elevation: 1030 Slope: 0 Aspect: 0 Dominant Tree Species: Pinus ponderosa Name: Site 5 "Metolius Fertilized" Location: 44 25' (N) 121 40' (W) Elevation: 1030 Slope: 0 Aspect: 0 Dominant Tree Species: Pinus ponderosa Name: Site 6 "Juniper" Location: 44 17' 30" (N) 121 20' (W) Elevation: 930 Slope: 0 Aspect: 0 Dominant Tree Species: Juniperus occidentalis Study plots: See maps, submitted separately. Sites 2,4 and 6 contain one plot each, chosen to represent a uniform and representative sample of the area. Site 1 contains 2 plots, one containing primarily western hemlock and one containing primarily red alder. Sites 3 and 5 contain one fertilized and one unfertilized plot at each location. Study purpose and goals: These data are part of the OTTER (Oregon Transect Terrestrial Ecosystem Research) data set. The OTTER project is designed to study the ability of remote sensing to detect biophysical characteristics of plant canopies at six sites along an east-west transect across central Oregon. Formats 1 and 2 contain meteorological data from weather stations at each of the sites. Formats 3 and 4 contain leaf chemistry data for the sites. The remote sensing information that corresponds with these data sets are on file in the PLDS data storage at the Ames Research Center, Moffett Field, CA (contact Gary Angelici at the Ames Research Center for more information). Experimental/Sampling Design: Meteorological Data: Beginning in the summer of 1989, a meteorological station was established at five sites. The station used for site 5, Metolius, also served for site 6, named Juniper. The meteorological stations (Campbell Scientific Instruments, Inc., Logan, UT) were located no more than 15 km from the forest stand. Air temperature, precipitation, relative humidity and total incident shortwave solar radiation (400-1100 nm) were collected every minute and then integrated or averaged hourly and recorded on an internal data logger. At approximately one month intervals, the data logger files were transferred to the memory on a portable computer. Through the course of the study, we detected some instrument problems. Leaf Chemistry Data: At each sampling period, five branches were shot from the canopy at random locations within each plot. In general, samples came from middle positions within the canopies; exceptions are noted in the data sets. At site 3 samples were taken along the roads bordering the two plots after December, 1989 (in order to obtain 'sun' foliage from this very dense canopy). Before January, 1990 samples from site 3 are probably 'shade' foliage. Samples from all other sites are 'sun' foliage. Leaf samples were taken at all sites within two weeks of each the five OTTER multiple aircraft campaigns for remote sensing data. At site 3 additional samples were taken to provide monthly data. Methods: Meteorological Data: Beginning in approximately June 1990, the relative humidity data from four of the stations (excluding site 4) began to decline from expected values. Readings decreased randomly in discrete steps due to a decrease in the sensor sensitivity resulting from the moist climate of Oregon. The data were corrected using the logic developed by Running and others (1987) in which minimum temperature serves as an approximation of dew point temperature, with relative humidity then varying by a known function with daytime temperature. When this was tested against earlier calibrated data, the procedure provided a good agreement with the observed relative humidities at sites 2 and 3 (R2 = 0.84 and 0.79, respectively). Humidity correction dates (1990) for each station is as follows: Site 1, June 1; Site 2, April 1; Site 3, April 1; Site 4, no correction; Site 5, April 1. Separately, at site 4, named Santiam Pass, heavy snow pack conditions necessitated the removal of the meteorological station for a 5 month period (January 1 to May 8, 1990). Comparable data were obtained from a nearby meteorological station operated by the Oregon Department of Transportation which reports in the NOAA monthly climate data summaries. Leaf Chemistry Data: Foliage was removed from sampled branches and placed on ice after collection. Within a few hours, representative samples were taken for specific leaf area analysis and the remainder of the foliage was frozen at -60 C. Frozen samples were shipped to the Ames Research Center for chemical analysis. At Ames, samples were freeze-fried using a cold trap at or below -40 C at a pressure not greater than 3 PA (0.02 mm Hg) for 48 hr., and stored at room temperature in plastic bags until analyzed. Moisture content of freeze-dried samples was determined by oven-drying at 65 C for 48 hr., and was used to convert chemical concentrations to an oven-dry weight basis. Biochemical Analysis: Reference samples (Standard Reference Material, 1976, 1982) were included in all analyses to ensure uniformity in the methods. At least three references were included in every group of 40 samples analyzed. In addition, 2-4 duplicates of at least three canopy samples were included in all analytical runs; for lignin and cellulose, all samples were run in duplicate. Total nitrogen and total phosphorus were measured with a Technicon Autoanalyzer II after samples were digested in block digester using a sulfuric acid-mercuric oxide catalyst (Technicon Instruments Corporation, 1977). Chlorophyll was extracted in acetone buffered by CaCO3 and concentration determined by standard spectrophotometric techniques. Free amino acids were determined by a colorimetric method using ninhydrin (Lee and Takahashi, 1966). A potassium permanganate method was used on acid detergent fiber to determine lignin (Van Soest and Wine, 1968). Cellulose was measured by loss of weight by ashing of lignin-free fiber. Sugars were removed from tissue samples using methanol-chloroform-water, and the residue was analyzed for starch (Matson and Waring, 1984). Sugars isolated in the water-methanol phase were measured using an anthrone colorimetric procedure (Hazid and Neufeld, 1964). References: Sugar: Hazid, W.Z. and Neufeld, E.F. 1964. Quantitative determination of starch in plant tissue. IN R.L. Whistler, R.J. Smith, and J.N. BeMiller, eds. Methods In Carbohydrate Chemistry. Academic Press, NY. Free Amino Acids: Lee, L. and T. Takahashi. 1966. An improved colorimetric determination of amino acids with the use of ninhydrin. Analytical Biochemistry 14:71-77. Starch: Matson, P.A. and R.H. Waring. 1984. Effects of nutrient and light limitation on mountain hemlock: susceptibility to laminated root rot. Ecology 65:1517-1524. Standards: Standard Reference Materials, 1976, 1982. Citrus leaves (SRM # 1572, DEC., 1982) and pine needles (SRM # 1575, Oct., 1976). National Institute of Standards and Technology, United States Department of Commerce, Gaitherburg, Maryland, 20899. Total Nitrogen/Total Phosphorus: Technicon Instrument Corporation. 1977. Individual/simultaneous determinations of nitrogen and/or phosphorus in BD acid digests. Industrial Method Number 329-74W. Technicon Instrument Corporation, Tarrytown, New York. Lignin/Cellulose: Van Soest, P.J. and R.H. Wine. 1968. Determination of lignin and cellulose in acid-detergent fiber with permanganate. Journal of the Association of Official Analytical Chemists 51:780-785. Specific Leaf Area (SLA): Between 20 and 30 cm2 of leaf tissue was removed randomly from the sample and placed on transparent tape. Projected leaf area was determined with a LiCor 3100 leaf area meter. Then leaf tissue was removed from the tape, dried to constant weight at 70 C, and weighed. Intercepted Photosynthetically Active Radiation (IPAR): We estimated IPAR by measuring the tree canopy transmitted radiance at each site, assuming the remainder is either absorbed or reflected. IPAR for only the trees was measured, with no attempt to estimate the influence of the understory vegetation on radiation interception. To determine tree canopy transmittance of photosynthetically active radiation we used a sunfleck ceptometer (Decagon Devices, Inc., Pullman, WA). The instrument measures instantaneous fluxes of solar radiation in the photosynthetically active region (PAR 400-700 nm). Measurements at all sites were made on cloudless days during July-August 1991. To minimize shadow effects, measurements were taken between 1200 to 1400 local solar time. Depending on the variability of the overstory, below canopy PAR was sampled at least 200 to 60 points along north-south and east-west transects. At each sample point the instrument was held level and turned in a circle to collect 20 measurements of PAR at 150 increments. These 20 measurements were then averaged and stored in the instrument's memory. Total incident PAR was measured in a nearby clearing or road at the beginning and end of the sample period and at intervals of approximately every 10 minutes during the sample transects. Canopy transmittance (Qi/Qo) was calculated by dividing the average below-canopy PAR (Qi) by the average incident PAR (Qo). Percent intercepted PAR (IPAR) was calculated from the formula: IPAR = (1 - Qi/Qo) ù 100 Trees Per Hectare and Basal Area: To establish patterns of above-ground biomass and productivity we sampled trees at study stand at all sites, 1-6. We selected at least 20 circular plots of 50 m2 each randomly in each stand. We measured the diameter at breast height (dbh; diameter at 1.37 m) of every tree >5 cm in diameter in each plot. We used tree counts and basal area measurements for the plots to compute average numbers of trees ha-1, and to estimate the relative contribution each tree species to the total basal area. Leaf Area Index (LAI) LAI was estimated after the method of Pierce and Running (1988), which used the relation: LAI = -ln(Qi/Qo)/k where k is the empirically determined extinction coefficient that for conifers has been found to range between 0.4 and 0.65 (Jarvis and Leverenz 1983). In this study, K was assumed to be 0.5, which is a good approximation for conifers (Pierce and Running 1988). For the alder stand (1A) a K value of 0.6 was used as an average for deciduous canopies (Jarvis and Leverenz 1983). References Jarvis, P. G. and Leverenz, J. W. 1983. Productivity of temperate, deciduous and evergreen forests. Pages 133-144 in O. L. Lange, C. B. Osmond, and H. Ziegler, editors. Physiological plant ecology IV. Springer-Verlag, New York, New York, USA. Pierce, L. L., and S. W. Running. 1988. Rapid estimation of coniferous leaf area index using a portable integrating radiometer. Ecology 69:1762-1767. Above-Ground Tree Woody Biomass To establish patterns of above-ground biomass and productivity we sampled trees at study stand at all sites, 1-6. We selected at least 20 circular plots of 50 m2 each randomly in each stand. We measured the diameter at breast height (dbh; diameter at 1.37 m) of every tree >5 cm in diameter in each plot. We used tree counts and basal area measurements for the plots to compute average numbers of trees ha-1, and to estimate the relative contribution each tree species to the total basal area. Stem, bark, and branch biomass was computed for each species in the sites using allometric relations developed for that species from destructive samples in the Pacific Northwest ((Bormann 1990 (sitka spruce), Gholz et al. 1979 (all other species)). We derived an estimate of total above-ground standing woody biomass by multiplying the measure of average weighted basal area per ha for each species by the biomass regression equations. References Bormann, B. T. 1990. Diameter-based regression models ignore sapwood-related variation in Sitka spruce. Canadian Journal of Forest Research 20:1098-1104. Gholz, H. L., C. C. Grier, A. G. Campbell, and A. T. Brown. 1979. Equations and their use for estimating biomass and leaf area of Pacific Northwest plants. Research Paper 41. Oregon State University, Forest Research Laboratory, Corvallis, Oregon, USA. Tree Foliage Biomass To convert from area to foliage biomass, we applied specific leaf areas (cm2 gm-1 dry weight) measured on foliage samples collected at the sites. In July five branches were shot from mid-canopy from dominant representatives of all of the major tree species at the 6 sites. Representative samples of needles from each branch were analyzed for fresh needle area (one-sided) with the LI-COR leaf area meter (LAI-3100; LI-COR inc., Lincoln NE), and then dryed at 700C to a constant weight and then weighed. The average specific leaf area of the five branches was then estimated and these values were then pooled with the averages for the other tress to provide a site average. These values were then applied to the LAI estimates from light transmittance (ceptometer, K = 0.5) to yield total foliage biomass (Mg ha-1). Above-Ground Tree Net Primary Production (ANPP) Woody tree growth was determined by annual tree dbh changes estimated from measurements of growth rings. Increment cores were taken from a random selection of trees in each sample plot beginning with an initial random choice and then every fifth tree in sequence. Measurements were made of the current-year's growth (1990) and of the previous five years. No significant difference was found between the current year-growth increment and the average of the previous five years for any of the sites. As a result, the five year average growth increments were used to compute the average annual increment for each site. These values were then applied to the species regression relationships and average trees per ha to estimate woody biomass production (Mg ha-1 yr-1). In order to gauge patterns of foliage biomass production across the transect we measured the fraction of new growth in the summer during maximum canopy development. Five branches were collected from each of the species on the sites and specific leaf areas (cm2 gm-1 dry weight) were measured on subsamples of current year age class and on subsamples of all other age classes. These values were then pooled for each site and used to provide an estimate of percent new production. The estimate of percent foliage production was applied to the estimate of total foliage biomass to provide yearly foliage production (Mg ha-1 yr-1). No measurements from Santiam Pass stand (site 4) were collected due to extensive spruce budworm damage. Instead, Gholz's (1982) estimate of new foliage growth fraction for a similar subalpine stand was used to compute total foliage production for site 4. Total annual above-ground net primary production (ANPP) of the trees was calculated by adding the woody biomass increment and foliage production estimates. References Gholz, H. L. 1982. Environmental limits on above-ground net primary production, leaf area, and biomass in vegetation zones of the Pacific Northwest. Ecology 63:469-481. Abstractor: John Runyon, Barbara Yoder Principal Investigator: Richard Waring Date: April 15, 1992