SNF FOREST PHENOLOGY/LEAF EXPANSION DATAEntry ID: SNF_LEAF_EXP
Abstract: The purpose of the SNF study was to improve understanding of the relationship between remotely sensed observations and important biophysical parameters in the boreal forest. A key element of the experiment was the development of methodologies to measure forest stand characteristics to determine values of importance to both remote sensing and ecology. Parameters studied were biomass, leaf area ... index, above-ground net primary productivity, bark area index and ground coverage by vegetation. Thirty two quaking aspen and thirty one black spruce sites were studied. Sites were chosen in uniform stands of aspen or spruce. Use of multiple plots within each site allowed estimation of the importance of spatial variation in stand parameters. Deciduous vegetation undergoes dramatic changes over the seasonal cycle. The varying amount of green foliage in the canopy effects the transpiration and productivity of the forest. Measurements of changes in the canopy and subcanopy green foliage amount over the spring of 1984 have been made. From above the subcanopy, photographs of the aspen canopy were taken, pointing vertically up. The photographs were taken at two locations in sites 16 and 93 on several different days. Foliage coverage was determined by overlaying grids with 200 points onto the photos of the canopy. The number of points obscured by vegetation were counted. These counts were adjusted for the area of the branches, which had been determined by photos taken before leaf out. The number of foliage points were then scaled between zero, for no leaves, to one, for maximum coverage. Subcanopy leaf extension was measured for beaked hazelnut and mountain maple, the two most common understory shrubs. For selected branches on trees in sites 16 and 93, the length and width of all leaves were measured on several days. These measurements were used to calculate a total leaf area which was scaled between 0 and 1 as with the aspen. The aspen canopy measurements have been combined with the subcanopy measurements and are available in this data set (i.e., SNF Forest Phenology/Leaf Expansion Data). These measurements of leafout show that the subcanopy leaf expansion lags behind that of the canopy. Subcanopy leaf expansion only begins in earnest after the canopy has reached nearly full coverage.
Data Set Citation
Dataset Originator/Creator: GOETZ, S.J.HALL, F.G.HUEMMRICH, K.F.NICKESON, J.E.STREBEL, D.E.WOODS, K.D.
Dataset Title: SNF FOREST PHENOLOGY/LEAF EXPANSION DATA
Dataset Release Date: 1996
Dataset Release Place: Oak Ridge, Tennessee, U.S.A.
Dataset Publisher: Oak Ridge National Laboratory Distributed Active Archive Center
Data Presentation Form: Online Files
Dataset DOI: doi:10.3334/ORNLDAAC/180Online Resource: http://mercury.ornl.gov/ornldaac/send/query?term2=180&term2attribut...
Start Date: 1984-05-10Stop Date: 1984-06-12
ISO Topic Category
Data Set Progress
Role: TECHNICAL CONTACT
Phone: (301) 405-1297
Fax: (301) 314-9299
Email: sgoetz at geog.umd.edu
University of Maryland Dept of Geography LeFrak Bldg
City: College Park
Province or State: MD
Postal Code: 20742
Role: DIF AUTHOR
Phone: (865) 574-7447
Email: uso at daac.ornl.gov
ORNL DAAC User Services Office Oak Ridge National Laboratory
City: Oak Ridge
Province or State: TN
Postal Code: 37831-6407
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 1996-10-24
Last DIF Revision Date: 2012-09-11