Navigation Links
400-year study finds Northeast forests resilient, changing

A joint Harvard-Smithsonian study released today in the journal PLOS ONE reveals how much -- and how little -- Northeastern forests have changed after centuries of intensive land use.

A hike through today's woods will reveal the same types of trees that a colonial settler would have encountered 400 years ago. But the similarities end there. Jonathan Thompson, research associate at the Smithsonian Conservation Biology Institute and lead author of the new study, explains, "If you only looked at a tree species list, you'd have the impression that Northeast forests haven't changed. But once you start mapping the trees, and counting them up, a different picture emerges." Thompson adds, "In some ways the forest is completely transformed."

To draw these conclusions, Thompson and his colleagues compared colonial-era tree records to modern US Forest Service data across a 9-state area stretching from Pennsylvania to Maine.

Their results show stark contrasts between pre-colonial forests and today. Maples have exploded across the Northeast, their numbers increasing by more than 20 percent in most towns. Other tree types have declined sharply. Beeches, oaks, and chestnuts show the most pronounced loss -- big trouble, Thompson notes, for wildlife that depend on tree nuts for winter survival.

Pine numbers have shifted more than any other tree type, increasing in some places, decreasing elsewhere. Thompson pins this variability to ecology and economy: "Pine is valuable for timber, but quick to return after cutting. It has a social and environmental dynamism to it."

The nine states in the study share a similar -- and notable -- forest history: during the 18th and 19th centuries, more than half the forestland was cleared for agriculture and cut for timber. Most farms were eventually abandoned, and during the 20th century, forests returned. Today about 80 percent of the Northeast is forested.

Driving the study is a historical data source that has never been analyzed at such a massive scale: the maps and notes of the earliest colonial surveyors. These scribbles and dots on old records document individual "witness trees" -- trees mapped between 1650 and 1850 to designate property boundaries when towns were first established.

Charlie Cogbill, an ecologist on the research team, spent three decades compiling these early records from the public archives of nearly 1,300 towns. The massive geo-database he built pinpoints the location of more than 350,000 witness trees, forming the basis of this study.

David Foster, co-author of the study and director of the Harvard Forest in Massachusetts, explains, "It is critical to understand the nature and scale of forest change triggered by human impacts. Charlie's effort to amass the witness trees provides a serendipitous window into the region's earliest forests, enabling us to assess the cumulative effect of centuries of land use and climate change."

Even 200 years later, the legacy of colonial farming remains the most powerful factor in determining modern forest composition -- more powerful than regional climate, soil conditions, and many other factors. "To get a sense of how much a forest has changed, the first question to ask is how extensively the area was farmed over the past two centuries," says Dunbar Carpenter, co-author of the study and research assistant at the University of Wisconsin-Madison. If more than half the town was farmed, he adds, local forests have probably diverged a good deal from their pre-colonial condition.

Across the board, reports the study, these changes have made modern forests more homogenous and less responsive to small changes in temperature and precipitation. Despite forest clearing, widespread logging, fires, climate change, invasive pests, and disease, the Northeast remains the most heavily forested region of the country.

"The overriding theme of this forest region is resilience in the face of multiple impacts," notes Foster. "This is an important lesson for the future. If we do not replace forests with houses and pavement, they will endure future challenges as well."

Thompson echoes this theme of resilience. "The Northeast wants to be a forest," he says. "If you stop mowing your lawn, you'll get a forest. That's essentially what we did in the mid-1800s -- we stopped mowing fifty percent of the landscape. What happens ecologically in the wake of that? The Northeast is the first place where we've watched it happen."

And the story is still unfolding.


Contact: Clarisse Hart
Harvard University

Related biology news :

1. UCSF receives $4.5M to study value of gene sequencing in newborns
2. First study to investigate the human genome in multiple sclerosis
3. Red cedar tree study shows that Clean Air Act is reducing pollution, improving forests
4. Penn study: Shutting off neurons helps bullied mice overcome symptoms of depression
5. Type 2 diabetes study to examine role amylin plays in disease
6. Cell study offers more diabetic patients chance of transplant
7. CU study relies on twins and their parents to understand height-IQ connection
8. Rice, MD Anderson researchers win NIH grant to study protein networks
9. Study adds lung damage to harmful effects of arsenic
10. UCI-led study reveals how SARS virus hijacks host cells
11. Human brains are hardwired for empathy, friendship, study shows
Post Your Comments:
(Date:10/29/2015)... Oct. 29, 2015  Rubicon Genomics, Inc., today ... distribution of its DNA library preparation products, including ... new ThruPLEX Plasma-seq kit. ThruPLEX Plasma-seq has been ... of NGS libraries for liquid biopsies--the analysis of ... prognostic applications in cancer and other conditions. Eurofins ...
(Date:10/27/2015)... YORK , Oct. 27, 2015 In ... major issues of concern for various industry verticals such ... is due to the growing demand for secure & ... in various ,sectors, such as hacking of bank accounts, ... for electronic equipment such as PC,s, laptops, and smartphones ...
(Date:10/26/2015)... and LAS VEGAS , Oct. 26, ... , an innovator in modern authentication and a founding ... the launch of its latest version of the Nok ... organizations to use standards-based authentication that supports existing and ... Authentication Suite is ideal for organizations deploying customer-facing applications ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... Israel , Nov. 24, 2015  Tikcro Technologies Ltd. (OTCQB: TIKRF) ... on December 29, 2015 at 11:00 a.m. Israel ... Electra Tower, 98 Yigal Allon Street, 36 th Floor, ... of Eric Paneth and Izhak Tamir to the ... Rami Skaliter as external directors; , approval of an amendment to ...
(Date:11/24/2015)...  Twist Bioscience, a company focused on synthetic ... Bioscience chief executive officer, will present at the ... 2015 at 3:10 p.m. Eastern Time at The Lotte New ... --> --> About Twist ... on Twitter. Sign up to follow our Twitter ...
(Date:11/24/2015)... ... 24, 2015 , ... InSphero AG, the leading supplier of easy-to-use solutions for ... Aregger to serve as Chief Operating Officer. , Having joined InSphero in ... and was promoted to Head of InSphero Diagnostics in 2014. There she ...
(Date:11/24/2015)... - ProMetic Life Sciences Inc. (TSX: PLI) (OTCQX: PFSCF) ("ProMetic" ... , President and Chief Executive Officer of ProMetic, will be ... th Annual Healthcare Conference to be held at the ... st , at 8.50am (ET) and ProMetic,s management team ... presentation will be available live via a webcast accessible at ...
Breaking Biology Technology: