Field Journal: What forest ecology research looks like on the ground

Julia Tatum, a first-year Environmental Science graduate student at Western Washington University, scans the dense forest underbrush around her, decides on a direction, grabs the end of a cloth measuring tape, and pushes off into the thicket to mark the edge of her sample site with surveyor’s tape.

After three steps, Tatum is completely lost from view, the colors of her t-shirt and braided hair swallowed by greenery so dense it almost seems unnatural. But here, along the banks of the Nooksack River’s South Fork near Acme, Washington, amid almost impenetrable swales of gooseberry, salmonberry, salal and sword fern, it is perfectly natural and, according to Tatum and her undergraduate research assistant, Nicole VandePutte, par for the course.

“This isn’t even that bad,” the disembodied voice of Tatum says from the underbrush 10 feet ahead. “At least it’s not blackberry.”

Just the word “blackberry” causes VandePutte to flinch as she remembers past sample plots from her summer of work with Tatum that were not nearly as hospitable as this one.

“Blackberry is the worst,” she confirms, as the breeze causes a momentary shower, shaking the drops from last night’s rain from the tree canopy onto the forest floor.

 

Building a forest inventory

Tatum and VandePutte have been collecting data for this project since July 1 at sites up and down all three forks of the Nooksack: the North Fork, Middle Fork, and now the South Fork.

Funded by the Nooksack Tribe, Tatum’s project involves a detailed tree inventory from 100 plots just like the one she and VandePutte are preparing to sample.

Tatum scans for the retroreflector target barely visible on the tree in the middle of the picture.

Every tree in each sampling site with a diameter of 10 centimeters or larger is laboriously cataloged and inventoried to build a riparian-habitat database that the tribe can use in its salmon restoration efforts; the Nooksack is home to all five native salmon species: chinook, coho, chum, sockeye and pink salmon, as well as steelhead, the anadromous form of the rainbow trout.

“It is vitally important to build a baseline of knowledge about the state of these riparian forest areas along the three forks of the river,” Tatum said. “An inventory of these trees gives the tribe something to work with and better understand where the healthy riparian zones are, and where there might be areas that need active intervention.”

Healthy riparian habitat provides shade to the river, keeping its water cooler — vitally important for salmon, especially as temperatures continue to rise and the glaciers and snowfields that feed to the Nooksack shrink.

Each plot, once it is measured, is then surveyed using a Leica total surveying station borrowed for the summer from the WWU Geology Department. The total station uses lasers to measure vertical and horizontal angles and distances, perform triangulations and calculate slope angles.

“This isn’t even that bad,” the disembodied voice of Tatum says from the underbrush 10 feet ahead. “At least it’s not blackberry.”

The total station sits at the center of each plot, and once the edges are identified, VandePutte takes another tape measure, the total station’s mirrored retroreflector target (which looks like a bright orange wizard’s staff) and heads to the first tree. She calls out its species, the diameter of its trunk in centimeters, and whether it is “dominant,” meaning the top of the tree reaches the top of the canopy and could be viewed from above.

“Bigleaf maple … 44 … it’s dominant,” says VandePutte over the din of a pileated woodpecker hammering a nearby deadfall.

Tatum records all this information in her log. VandePutte then holds the staff up to the trunk; Tatum squints through the eyepiece of the total station as its laser rangefinder attempts to find the retroreflector atop the staff. Because of the dense understory, finding an unobstructed path from the total station to the target is often quite a difficult task; my job is to be the designated fern flattener and salmonberry pusher.

“Up a little. A little more. To my left a little. OK, can you turn it to face me a bit?”

Once Tatum sees the target, she presses a button and the rangefinder attempts to connect with the target atop the staff; a beep signals the connection has been made and the tree’s location logged via GPS.

“Got it,” says Tatum, and VandePutte begins moving to the next tree. This process is repeated for the 30 or so trees within the sample plot. Once all trees are sampled, the edge tape is retrieved, the total station broken back down and stowed away into the backpack that Tatum swings onto her shoulders.

She breaks out her compass.

“Trail is back THAT way,” she says, pointing, and VandePutte moves off to find the easiest route. They are working today on sampling sites off of the 1,000 Puddles Trail at the end of the Saxon Road. They have completed two sampling sites already today and have two more to do, but first it is lunchtime — so the pair find a soft place to sit and break out the Tupperwear as a bald eagle calls from a snag perched over the river.

“We’ve seen plenty of those this summer,” said Tatum, a native of Port Angeles.

With their sampling season drawing to a close, the pair reflected back on the almost three months of fieldwork completed for the project, recalling with a laugh the day a bobcat ran right through their plot.

“It never even gave us a second look,” she said. “Of course, the first thing we wondered was what was chasing it … but we never found out.”

They’ve seen a couple of bears (all very well behaved, added Tatum) and a coyote, but mostly they have seen trees, thousands of them, in all shapes and sizes, on flat river bottoms like today to terrain on the North Fork so steep it was almost impossible to sample.

VandePutte, an Environmental Science major from Seattle, said she leapt at the opportunity to apply for the summer job working for Tatum; she knew it would be invaluable fieldwork experience.

“It’s been an amazing summer … I have learned so much,” she says, adding that working on this project has opened her eyes to what project-based fieldwork is all about.

Tatum said the competition for VandePutte’s position was fierce, and was easily the most stressful part of preparing the project.

“I had over 20 applications,” Tatum said. “So many qualified students applied. It was a really tough choice, but Nikki has just been incredible. I don’t know what I would have done without her.”

 

Next steps: analysis and comparison

Tatum said once the fieldwork is done she will compare the data they have so laboriously gleaned since July with the LIDAR imagery of the same sample sites shot by the U.S. Geological Survey; one of her crucial determinations will be how the LIDAR imagery jibes with the field database.

“I came back to Western just so I could work on this project for my thesis,” says Tatum; the hundreds of hours spent gathering data this summer haven’t diminished her zeal for the project, they seemed to have focused it even more keenly.

“Getting a better understanding of how remote surveying with LIDAR can be used on stand-assessment projects like this one, especially when we are comparing it to freely available USGS LIDAR data, is why I am doing this work,” she says.

A raven croaks from a nearby treetop as the river rumbles down its cobbled path a stone’s throw from where we sit; the Nooksack itself remains completed hidden by the wall of greenery, an apt metaphor for the team’s summer of hard work.

“Data remains a mystery until you collect it,” says Tatum. “And we have certainly been collecting it.”

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