Tony Cheng is a professor in the Department of Forest & Rangeland Stewardship at and is Director of the Colorado Forest Restoration Institute (CFRI) at Colorado State University. Tony’s primary research interests are in forest governance, policy, and administration, with a focus on collaborative approaches to promote resilient social-ecological systems linked to forest landscapes. In his capacity as Director of CFRI, Tony oversees programs to develop, compile, and apply current knowledge through collaborative, adaptive management approaches to achieve forest restoration and wildfire hazard reduction goals.

What trends are you seeing in forestry research right now?

It varies regionally and by topic. In the western U.S., in the forest ecology space, there seems to be a lot of work on disturbance interactions — the combined effect of changing climate, fire, insect epidemics, and human forest land use. The general story is that each disturbance can exacerbate the impact of subsequent disturbances, to the point where some places that were once forested are not regenerating to be forested again for the foreseeable future. This is especially the case with so-called dry forest types — those species that have evolved to be tolerant to droughts and lower-severity fires and insect outbreaks: Ponderosa pine, Jeffrey pine, sugar pine. Recent large and high-severity fires are not regenerating because: a) the size and severity of fires have created such large tree-less spaces on the landscape that the heavier seeds of these tree species can’t disperse across these spaces; and b) the climatic conditions under which seeds can establish and grow into baby trees (seedlings) are giving way to conditions that prevent seedling establishment and survival, i.e., hot, dry. There’s been a flush of research on this topic and a focus on the western U.S. Globally, there’s a line of research on how tree-level stress caused by changing climatic conditions (i.e., hot, dry) are leading to fairly large-scale and rapid forest die-offs.

On the social science side of forestry research, there’s a lot of interest in how to change forest governance structures and systems to be more participatory, adaptive and informed by risk analysis approaches. This line of inquiry stems from an acknowledgement that, both in the U.S. and globally, forest governance has historically been characterized by “command-and-control” by government agencies to exert management control over what’s viewed as a fairly static system. But with expanding science in the complex dynamics of forest ecosystems, loss of forest productivity and biodiversity, changing economies around forest use and management, grassroots demands for more participation by communities and stakeholders, and compounding, uncertain impacts of climate change, this governance approach is generally seen as a failure. Innovations in more adaptive, participatory forest governance are being spread across the globe, with research following in its path.

Another interesting social and economics research arena is how to better account for the non-market economic values of forest ecosystem services and incorporate those into value chains, either through payment-for-ecosystem-services exchanges or in trade-off analyses using various spatial-analytical optimization techniques. There’s a whole universe of forestry research and I’ve only touched on a few areas that I pay attention to. If you asked some operating in the space of forest biodiversity or conservation genetics, they’d give you a whole different answer!

Are Best Management Practices in forestry changing? If so, in what ways?

Looking back 30 to 40 years or so there’s certainly been a lot more attention to mitigating the effects of timber harvesting operations on biological diversity, wildlife habitat, water quality, aesthetic/scenic considerations, and recreation, among other values. To various degrees, federal, state, and local government policies either require best management practices to be used when approving forestry projects or make BMPs voluntary along with abundant education, technical, or financial assistance. State forestry agencies generally keep an eye on BMPs on non-federal public lands and private lands, while federal land agencies (i.e., US Forest Service) have their own system of measuring compliance. There are several certification programs that institute BMPs, such as the Forest Stewardship Council’s forest certification. There are other alternative forest certification programs, such the U.S. forest industry’s Sustainable Forestry Initiative and the EU’s Programme for the Endorsement of Forest Certification.

In the western U.S., there has been somewhat of a trend towards more ecology-based forestry on federal forest lands managed by the US Forest Service and Bureau of Land Management. These practices seek to mimic forest conditions that would have resulted with natural processes, like fire, windthrow, endemic insect mortality, and the like. Using so-called historic ‘reference conditions’ of forests unaffected by human disruption of natural processes, forest practices can be tailored to produce forest conditions more consistent with natural processes, rather than the more agricultural model of clearcutting and plantations. The ecology-based forestry model isn’t very widespread outside of federal forest lands because it’s not as economically efficient.

How do we measure forest health?

The most common way ‘forest health’ is measured in the U.S. is by estimating tree death by sources of mortality, especially insect and disease infestations. It’s a very tree-oriented basis. But it’s also efficient, replicable, and scalable using aerial detection survey methods that have been around for decades. It’s akin to how we measure the health of human populations with efficient, replicable, and scalable methods, such as percent of the population that are obese or with high blood pressure. These individual measures tell us something about overall population health, but they also miss the holistic nature of what ‘health’ is comprised of. There have also been efforts to measure forest health using “proxies” of an intact, functioning ecosystem. One example of using proxies is measuring the abundance and distribution of “keystone” species, such as the northern spotted owl in the Pacific Northwest’s Douglas-fir and western hemlock forests. If the owl populations are doing well, the entire forest ecosystem is functioning well. The most sensitive forest-dwelling avian and terrestrial wildlife species can make for reasonable proxies of forest health. We can also take measurements of water quality at the base of a watershed to determine if the physical, chemical, and biological attributes of the water vary with changes in forest uses and management. If those measures exceed a certain threshold, then these could indicate declining ecological functioning.

How is GIS being utilized in forestry management and research today?

How isn’t it being used? GIS is essential for any forest manager and researcher. For managers, GIS is a powerful tool to compile, analyze, store, and track over time many types of data for assessing forest conditions, risks, and trends, and for formulating, monitoring, and adapting management plans and activities. As a starting point, a forest manager would compile underlying topographic and soil map data to create an understanding of slopes, aspects, elevations, site productivity, and erosion risks. The manager would then add vegetation data layers to assess what tree species are occurring where on a parcel of land. Additional data on stand age and condition is beneficial to add into this veg layer, if available. GIS data is also often available from state wildlife agencies or state natural heritage programs delineating habitats for plants, birds, and animals of interest. Armed with these — and other data layers of interest — managers are able to make informed decisions about why and where to prioritize forest management activities that achieve the biggest bang for the buck. More advanced queries and analyses can be done in a GIS environment for research purposes, such as designing sampling strategies, or modeling fire behavior, vapor pressure deficit (an indicator of climate-induced plant stress), and forest vegetation change under different climate scenarios. Advances in satellite or airborne (airplane-mounted) remote sensing platforms are capturing forest attributes in ever finer resolutions, in some cases, sub-1 meter resolution. LiDAR is the latest craze (Light Detection and Ranging), but there’s also hyperspectral imaging devices that can capture ever finer bands of electromagnetic light energy to measure things like photosynthetic rates of grass across continents — metrics that one couldn’t imagine 20 years ago. There’s now so much spatial data being generated by satellites, airborne platforms, and drones that can be brought into GIS environments, making GIS indispensable to forest management and research.

What is the role of big data in forestry research today?

One example is that researchers are using wall-to-wall, multi-year satellite imagery to measure forest cover change over the past 4 decades. Brian Buma at University of Alaska-Southeast does a lot of this kind of work (https://link.springer.com/article/10.1007/s10661-017-6364-x). These large datasets can be used at fairly small geographic scales, such as a watershed, and linked with more local sources of data on precipitation, temperature, population growth, and conversion to nonforest land uses associated with either agriculture or urban/suburban growth and development. The data can also be used at the global scale to assess “hot spots” of forest loss risks and vulnerabilities due to natural and/or human disturbances. When paired with inventories and assessments of other biological attributes, like imperiled wildlife, or with data on demographic and economic changes, like poverty or displacement of communities, researchers can draw more confident conclusions about associative or causal linkages between changes in forest cover, biological diversity, and socio-economic and political factors. This wouldn’t have been possible even 10 years ago. Finer-resolution large datasets created by sub-30m resolution imagery (i.e., QuickBird satellites, LiDAR, NAIP — National Agriculture Imagery Program via US Dept of Ag.) also track changes at the tree level to estimate physiological attributes, like tree-level growth rates and carbon storage over time and over large areas. In turn, research results can be used at the international or national levels to drive investment and policy changes to conserve forest lands, or in inventories of greenhouse gas emission vs. sequestration.

How important is good soil and nutrient cycling to forest health?

The short answer: very important. Soil productivity is the foundation of all plant productivity. Surprisingly, many tree species have evolved to survive and thrive on very poor substrates. Check out this photo of a very old bristlecone pine growing out of what’s essentially bare rock. It’s not uncommon to see trees grow out of the tiniest ledges on the sides of sheer cliffs. It comes back to how one defines “forest health”.

What trends are you seeing in the policy arena related to forestry?

One trend witnessed both in the U.S. and globally is the so-called ‘devolution’ of authority over forest management from national governments to subnational governments (i.e., state, county) and community-based institutions and organizations. The theory is that the people and economies most closely tied to and affected by forest use and management have more incentive and are better equipped to steward forest resources compared to a large bureaucracy. The empirical testing of this theory is still being played out. Nonetheless, the US Forest Service is moving to a model of “Shared Stewardship” by which the federal and state governments share roles, resources, and responsibilities for forest stewardship of federal forests. This is being done without any constitutional or statutory changes, mostly through administrative fiat.

A second trend I keep track of is how to ‘economize’ the value of restoring, protecting, and enhancing the growth and sustainability of forests. This relates to one of the socio-economic trends in forest research I see. The logic is that, if society and markets are able to account for the ‘true’ value of forests, we’d see more investment in sustaining forests, rather than exploiting or converting them into non-forest uses (e.g., cattle farms or palm oil plantations). “REDD” has been an evolving policy arena globally. REDD = Reducing Emissions from Deforestation and Degradation. REDD is basically a way for developed carbon emitting countries to tax themselves and pay less developed countries with abundant native forests to not obliterate their forests. Results have been mixed so far, but REDD is still being pursued as one tool in the policy tool box.

What does the future of forestry look like?

Forestry will always have a future because societies all around the world rely on forests for a whole variety of purposes, uses, and values. Forestry as a field of knowledge and practice is equally about the biophysical aspects as it is about the human dimensions — individual uses, cultural values, political institutions, and economic uses associated with forests. Increasing population = increased demand for forests. At the same time, climate change is impacting forests across the planet, some in expected ways with warming and drying, but perhaps some in unexpected ways. For example, there may be places where conditions may become more conducive to forest establishment and growth as a result of changing climate conditions. We just don’t know yet. Because of all these factors, forestry will continue to have a place in the world. The challenge to us in the forestry profession and community is to clearly communicate the roles, contributions, and value forestry delivers to society.