Preparing for the Forests of the Future

A Picnic in Arnot Forest by Alison Mason Kingsbury (1961). Collection of The History Center in Tompkins County, used with permission.

A Picnic in Arnot Forest by Alison Mason Kingsbury (1961). The History Center in Tompkins County, used with permission.

By David Weinstein

Climate change will reshape our forests.

This reality is causing considerable concern among the growing numbers of small private forest owners who cherish and care for their woods.  Additionally, pressure is growing on public and institutional managers to keep the forests under their protection healthy and productive in the face of climate change.  However, neither group is sure what they should be doing to help forests adapt to new conditions.  A new applied research project at Cornell University will give both groups tools to understand what the changes will look like, and which techniques to employ in their forests to aide the adaptation process.

Throughout the forests of the U.S., climate change is exacerbating problems by weakening trees and increasing the prevalence of invasive species such as insects, pathogens, and competing non-native plants.  Warmer temperatures overall typically mean more bugs, weeds and pests that can survive winters (though not this one!).  These factors will greatly change the dynamics of native tree species survival by increasing the numbers of trees that weaken and die.  Climate change is already impeding the healthy development of the forests in the Northeast (see accompanying figure), as damaging insects new to our area have moved up from the south.  This is but one example of the new pressures on our forest resources.

Preparing for the forests of the future

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One great concern is the continued ability of forests to absorb excess carbon dioxide from the atmosphere and store it. Trees are one of our best defenses against worsening climate change as they are effective storage units for carbon, the most common greenhouse gas causing global warming.  It is equally important to ensure that these forests continue to offer opportunities to extract useful products, including building materials and biofuels.

The principle scientist of this effort, I have spent over 30 years examining the ways that forests all over North America develop.  I build and use computer models where I can alter conditions and let the computer evaluate how these changes will reshape the forests.  I’m then able to test management techniques in the models to see which are most likely to keep the forests growing in a healthy manner.

Although the management techniques developed in this research will give insight and opportunity to forest owners and managers throughout the United States, the initial test subjects are close to home, the forests of central New York.  These forests are good ones for first examination because they lie in a dynamic transition zone at the boundary between the northern hardwood forests and more southern central mixed oak forests, a zone where climate change is likely to be particularly damaging.  The forests here play a key role in capturing and removing excess carbon dioxide from the atmosphere and in providing the habitats that support a large diversity of species.

Working with a team of colleagues from the Department of Natural Resources at Cornell University, we are devising a set of methods of managing forests that can be evaluated in a computer model to see which management approaches reduce forest vulnerability to climate change. For example, by augmenting reproduction through protecting seedlings and saplings of species that will eventually fair much better under warmer temperatures, the forest can be given a head start toward its transition.  Modification of habitats within the forest can provide homes for both animal and plant species as they are being forced to migrate from the south to keep pace with a warming climate.  Through targeted harvesting, trees ill-suited to survive are removed to release light, water, and nutrients.  These resources are then available for trees better adapted to the new climates, so that they have a growth edge and become quickly established.

The model we are using was developed by the United States Forest Service for the northeastern region and extensively tested against long-term forest growth data locally for a range of different types of forests. It combines the most current understanding of tree-climate change relationships to help us to design ways to further adapt forests to new climatic conditions. It is being used to identify the vulnerability of each major upland forest type in central New York to the influences of climate change, quantifying which forest types are at risk and what levels of tree mortality are anticipated. This tool projects the long-term consequences of the impacts of changing conditions, and identifies the strategies that effectively reduce the susceptibility of these forests to deterioration.

Although another year of research and development remain before the tool is ready for the public, this project will culminate in an interactive web site that will allow forest landowners and managers to examine different scenarios of the ways climate is likely to change and, as a result, change the forests. This web site will contain a toolbox of resources users can access to identify management options they might employ.

One of the tools in this toolbox, a version of the forest simulation model tailored to run on a web site with a user-friendly interface, will offer a dynamic insight into the interaction between climate change and forests.  Forest landowners will be able to enter descriptions of their own forest, run the simulation model online, and receive visual images of what their forest will look like with the changes likely over the next century.  They will then be able to test management strategies themselves to identify which will meet their goals under climate change.

These tools will allow forest owners and managers to gain an in-depth understanding of the sequence of effects, such as the death of canopy trees, that culminate in major changes. Visualization tools will help users gain confidence in the ways different management techniques could shape the future health of their forests, and to implement strategies for sustainable forest wood and biofuel extraction that are complementary with supporting a diverse set of species and an attractive forest.  By exploring the resources in the toolbox, managers can chart a road map to adapt their forests to thrive under anticipated future climate conditions.

Preliminary test results indicate that many of the services provided to human society by central New York forests can be greatly enhanced by using management strategies tailored for our new age.  For example, management strategies in the model increased the absorption of excess carbon dioxide in a range of different forests by 25%, while other strategies increased biodiversity by 20%, pest resistance by 19%, and biofuel production by 32%.  By employing these management strategies, we can adapt forests that will be much more capable of providing the critical functions needed under future climates.

With much healthier forests that simultaneously resist disease and insect infestations and permit a sustainable harvest, forest owners and managers can help secure the ecosystem and financial benefits of these forests. By accelerating the absorption of excess carbon dioxide, they will position their forests to reduce the climate change problem our world is facing.  This toolbox will help us to adapt our forests to withstand the pressures already being brought by climate change, and create a landscape capable of being both sustainable and biologically productive under these changing climates.

David WeinsteinDavid Weinstein is a senior research associate in the Department of Natural Resources, Cornell University, and a faculty fellow at the university’s David R. Atkinson Center for a Sustainable Future.

Category: Climate Change Forum

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