BLOOMINGTON, Ind. -- Deep in the woods of Brown County, Mark Sheehan and Peyton Joachim don vests full of equipment and hike up hills and scurry down ravines. They stop on the uphill side of almost every tree to measure its diameter using a special measuring tape, and then either check an existing tag or place a new aluminum tag around the base of each tree.
They are working in 90-degree heat, with insects buzzing around their heads, to document all the trees in the five plots, called quadrats, that remain. In all, there are 625 20-meter quadrats within the 62 acres that are being studied as part of a Smithsonian Institution-funded project that is collecting data from forests around the world for scientists to study. The project, Forest Global Earth Observatories network or ForestGEO, has 51 long-term forest study sites in 22 countries around the world. At each site, the same precise measurements are taken of trees, with that data being compiled by researchers at the site and then uploaded to a database.
From June through August, Sheehan, a technician in the Indiana University biology department, led a four-person team that cataloged each tree with a diameter of 1 centimeter or more at breast height, which is 4.5 feet from the uphill side of the tree's base. Since classes at IU began in late August, it's been Sheehan, Joachim and a few others who worked to complete the project in late September.
When the project is completed, almost 30,000 trees will have been measured.
The 62-acre area of the forest can only be reached by hiking for almost an hour or riding in a jeep down a rutted, log-strewn dirt road. Large old-growth trees tower overhead, shading the forest floor where the researchers climb the hillside to begin cataloging trees in a new quadrat, this one on a hillside not far from a grove of young pawpaw trees.
"It's the oldest trees and it's the least disturbed area," Sheehan explained of the plotted area. He estimated some of the trees - red and black oak, black gum and pignut hickory - could be 160 years old.
"The work that we're doing is only descriptive work," he said. "It all gets put into a database that can be mined by researchers all over the world."
This is the second time the trees within the plot have been cataloged. The first time was in 2012, and that information is now part of the ForestGEO database.
Besides updating all the data that was given in 2012, this time Sheehan and the others are describing the trees to provide researchers with more than just the diameter and species of the trees. Specific terms must be used to describe the various aspects of the trees, including descriptions of the trees' canopies and how close a tree's branches and leaves are to the ground. This will help researchers better understand the role of each tree in the forest.
"A lot of people are tapping into the data to do these large data analysis and comparative studies," said Keith Clay, an IU distinguished professor of biology who served as director of the Lilly-Dickey Woods preserve from 2002 to 2014. The scientists are studying tree growth, patterns of mortality and those relationships in comparison to climate change and other factors, Clay said.
Clay and others at IU are eagerly awaiting the final data from this summer to be cataloged so they can begin to see what changes have taken place at Lilly-Dickey Woods.
"We're particularly interested in the drought of 2012," he said. "It was obvious, in collecting the data, that a lot of the trees had died (since 2012). Whether it's due to the drought or not is going to be hard to determine."
Clay said some species may have had higher mortalities in the past five years, including smaller sugar maple trees.
"This is something that climate scientists have said would happen with warming temperatures," he said. "Some species will not be able to handle the climate changes."
Clay said the data won't be available anytime soon.
"It's a huge effort, entering it in and double checking it and then analyzing it," Clay said. "I suspect it will be a couple years before we have a good handle on what's changed from 2012 to 2017."
Since Brown County is at the edge of the forested areas, with prairies just a little further west, Clay said data from Lilly-Dickey Woods may be crucial to researchers. "You might expect that the forest here could be right on the edge of the climate change," he said.
For each of the forests in the ForestGEO project, the people who contributed data are considered authors when a research paper or article is published. Clay, Richard Phillips, a professor of biology at IU and director of the IU Research and Teaching Preserve, and Dan Johnson, who led the 2012 tree census while he was a graduate student at IU, were authors in a recent article in Science magazine using data from the Lilly-Dickey Woods. The article shares results of a study that analyzed more than 3,000 species of trees in 24 forest plots around the world. The study found that young trees in areas with high concentrations of the same species did not fare as well as trees growing in areas with a more diverse grouping of tree species. The hypothesis presented from the study is that seedlings are more likely to be attacked by diseases and pests if they are near their parents, Clay said.
Another study using data from Lilly-Dickey Woods is looking at the role of big trees in a forest and how they contribute to the growth and biomass of the forest, Clay said.
"The pace of the people using the data is picking up," he said. "It's a good thing for IU and the teaching preserve."
Source: The (Bloomington) Herald-Times, http://bit.ly/2xRfW0m
Information from: The Herald Times, http://www.heraldtimesonline.com