Don’t call them tree-huggers – more like big tree-measurers

  • Dode Gladders, a forester and field specialist with UNH Cooperative Extension, looks up at a tree as he led a training session Friday for the New Hampshire Big Tree Program. GEOFF FORESTER / Monitor staff

  • Dode Gladders (left), a forester and field specialist with UNH Cooperative Extension, and Jim Sargent measure a Tulip tree on the grounds of the Canterbury Shaker Village on Friday. GEOFF FORESTER photos / Monitor staff

  • A group of Merrimack County officials take part in a New Hampshire Big Tree Program training session Friday.

  • Dode Gladders, a forester and field specialist with UNH Cooperative Extension, looks up at a tree the group is about to measure as he led a training session with Jim Sargent on Friday, April 26, 2019 for the New Hampshire Big Tree Program. GEOFF FORESTER—Monitor staff

  • Dode Gladders, a forester and field specialist with UNH Cooperative Extension, looks down as he works on measuring a Tulip tree on the groumd of the Canterbury Shaker Village as he led a training session Friday, April 25, 2109 for the New Hampshire Big Tree Program. GEOFF FORESTER—Monitor staff

  • In this March 24, 2017 photo, Kevin Martin, state coordinator for New Hampshire's Big Tree Program, measures the circumference of a European Beech tree in Portsmouth, N.H. The program encourages residents to search their city's streets, backyards and woods for the state's largest trees. (AP Photo/Michael Casey) Michael Casey

  • Jose Sanchez of Miller Amusements prepares the lighted sign for the Orbiter ride at the Deerfield Fair Monday. The fair runs Thursday through the weekend.

Monitor staff
Published: 4/26/2019 6:04:05 PM
Modified: 4/26/2019 6:03:55 PM

When it comes to determining the biggest trees in the county or state, accuracy is important. But don’t get carried away.

“Crown spread can be a little subjective. No two people would measure it the same,” said Dode Gladders, a forester and field specialist with UNH Cooperative Extension, as he led a training session Friday for participants in the New Hampshire Big Tree Program.

Crown spread is a forest term for the diameter of a tree’s branches at their widest. It is the least significant of three measurements used to calculate total tree size for the national Big Tree program, along with circumference of the trunk and the tree’s height.

Combining those three gives a score used to determine the “biggest” tree – not necessarily tallest or widest or heaviest or oldest – for that species in your area. Some 50 people volunteer to hunt down and confirm these super specimens throughout the state’s forests and streets.

“We have one of the strongest, if not the strongest, Big Tree programs in the country,” said Mary Tebo Davis, a Natural Resources Field Specialist for UNH Extension who ran Friday’s training session at Canterbury Shaker Village. “We have all these volunteers, a state coordinator, county coordinators, and measurers.”

Ah, measurers – how do they do it?

Measuring trunk circumference is straightforward: At 4 ½ feet above the ground, run a tape measure around the trunk. Unless there’s a branch in the way, it’s easy. Assuming you have the equipment.

“I had to use a dog leash one day because I didn’t have a tape measure with me,” said Sue Lichty, a Sullivan County measurer and one of more than two dozen people who showed up for Friday’s training.

Trunk circumference is a necessary number to nominate a tree for the New Hampshire Big Tree Program. Any tree can be submitted via the website at; if it appears to be a reasonable candidate for a record, trained volunteers will gather more data.

Scores of tree species are listed for each of the state’s 10 counties, and the state itself. They even include some invasive species, such as the huge Norway maple next to the Soldiers Memorial Arch in front of the State House in Concord, which is the biggest such invader we known of in New Hampshire.

Tree height is a little trickier to determine. It requires a device called a clinometer, which looks like a cross between a stopwatch and a monocular. You stand 100 feet away, look through the clinometer to the base of the tree and then at the top of the tree, noting the two listings on the clinometer’s internal scale. Those listings, via a little mental arithmetic, give the height.

Gladders asked his troupe of six trainees, plus this reporter, to try their luck measuring the height of a huge, gorgeous tulip tree on the Shaker Village property. We arrived at values ranging from 70 feet to 100 feet; his result was 80 feet, which nobody else got.

“It takes practice,” he said. Just figuring out which branch is the tallest can be difficult.

As for crown spread, it is measured by looking up from the ground, eyeballing where you think the widest spot is in the tree, from drip-line to drip-line. That diameter is measured on the ground, then a measurement is made of the diameter taken at a right angle. Finally, the two figures are averaged.

Especially when trying to estimate crown spread in the middle of the forest with nearby trees in the way, it’s clear how different people could come to different conclusions. This is one of the reasons that crowd spread is the least important of the three measurements in a tallying a score – it gets divided by 4 before it is added in.

What’s the point of all this effort? Everybody agreed at the session that there’s something about being close to a really big tree that just seems worth it.

“These trees have been here 100 – 200 – 300 years. Think of the connection to history, to all that tree has witnessed,” said Donna Miller, a big tree volunteer.

Identifying truly big trees might alter the path of future development. Even the most ardent homeowner or builder might think twice about cutting down a tree if it’s on a website marked as the biggest of its kind in the county.

There are environmental benefits to finding and preserving big trees, too. Most of New Hampshire south of the White Mountains was cleared by 1840 to make sheep pastures, so truly old trees are rare. Those that were spared usually were on property lines, along stone walls, or just inaccessible.

“There are a number of species that focus on large, mature trees. They are needed for habitat,” said Tebo Davis.

“The biggest benefit is the awareness it brings to people. It gets them to look around, to look around in the woods, to pay attention,” she said.

The Big Tree program is run by UNH Cooperative Extension, the New Hampshire Division of Forests and Lands, and the Society for the Protection of New Hampshire Forests.

(David Brooks can be reached at 369-3313 or or on Twitter @GraniteGeek.)

David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog, as well as moderator of Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

Concord Monitor Office

1 Monitor Drive
Concord,NH 03301


© 2021 Concord Monitor
Terms & Conditions - Privacy Policy