LOCATION:
Bartlett Experimental Forest (C1, C2, C4, C6, C8, C9), Hubbard Brook (HBM, HBO, and HBCa), and Jeffers Brook (JBM and JBO).
METHODS:
We collected green leaves of American beech (Fagus grandifolia), yellow birch (Betula alleghaniensis), sugar maple (Acer saccharum), white birch (B. papyrifera), red maple (A. rubrum), pin cherry (Prunus pensylvanica), quaking aspen (Populus tremuloides) and bigtooth aspen (P. grandidentata) from 11 MELNHE stands in 2021 and 2022 during the last week of July and first week of August. Leaves were usually collected from three trees of each species in each plot, and we collected 9 leaves on average from each tree using a 12-gauge shotgun. Whole leaves with petioles attached and with minimal disease and insect damage were retained for chemical analysis.
Prior to chemical analysis, the selected leaves from each tree were weighed, scanned using a flatbed scanner to determine surface area with ImageJ, then dried and weighed again for dry mass. We also photographed the leaves collected from each tree to serve as a record for comparison.
We measured the area of all leaves from each tree at once using a binary image at 300 DPI in ImageJ. We also measured the area with and without holes. In cases where a leaf margin was torn (e.g., small insect bite at edge of leaf) and drawing a line to approximate where the margin would be would yield a more accurate area than leaving it as is, we closed the margin by drawing a thin line in ImageJ and calculated the leaf area with and without holes. This data package includes the copies of the images with fixed margins in a separate zipped folder.
In 2021, we measured both damaged and undamaged leaves for 20 trees to help assess the effect that damaged leaves might have on trait values. This data package contains the leaf area scans and photographs of those samples as well. The leaf area scans are in a separate zipped folder.
Area and mass measurements, nutrient concentrations, and other trait measurements can be found in the following EDI data package: https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-hbr.313.1