Will a nationwide forest inventory effort help save Colorado’s oldest trees?

Big tree hunters hunted rumors in the San Juan Mountains of southwestern Colorado. They had heard of massive trees hidden in rugged terrain, and during many visits they spotted and then walked the treetops that towered above the rest of the forest. The work, made in 2014 and 2015 by a cohort of arbor enthusiasts, broke a string of records for Colorado’s largest leaf-bearers. They found a 169-foot-tall Douglas fir, a 165.3-foot ponderosa pine, and a world-record blue spruce at a height of 180.6 feet. The wonder, says Austin Rempel, Durango-based senior director of reforestation for American Forests, a 150-year-old conservation organization focused on preserving forest ecosystems, is that “even today, we don’t know where all the old growth is.

A recent executive order could change that. In April, President Joe Biden signed a document calling for new standardized definitions of old-growth and mature forests and a national inventory of these forest types by April 2023. The project aims to protect the last relatively intact stands of forests complexes for the for the biodiversity they preserve and the carbon dioxide they extract from the atmosphere.

In Colorado, where few old-growth forests remain, the effort could make the most difference by protecting mature forests — younger forests that are beginning to show signs of old age — and reversing a centuries-old trend of old-growth disappearing. forests. But protections will not be easy as there is no consensus on which trees to include in either category.

“Creating a definition is very complex for old growth systems,” says Sara Husby, executive director of Great Old Broads for Wilderness, a grassroots national wilderness organization headquartered in Durango, “even in the Colorado, as it will vary depending on the latitude, elevation, vegetation, disturbance, history, and rainfall that the different forests receive here.

Foresters, natural resource managers and conservation groups — here in Colorado and across the country — have wondered how the same labels and criteria can apply to vastly different ecosystems and species. Even the public intervenes, publishes comments (you can provide comments here until August 30) for the US Bureau of Land Management and the US Department of Agriculture, which oversees the US Forest Service. “We’re all wondering what a national definition might look like,” says Marvin Brown, who heads the National Association of State Foresters’ forest management committee. (Colorado’s state forestry office declined to comment until the new definition is complete.) It’s much more complicated.

Tall ponderosa pines in the Hermosa Creek Wilderness area of ​​the San Juans. Photo by Robert T. Leverett/American Forests

Complications arise because trees are not so different from people: “mature” and “old” may be entirely separate traits. For example, a few centuries would be a long lifespan for a ponderosa pine, but that would hardly be considered beyond the first few years for a bristlecone pine, which can live for millennia. In fact, a Rocky Mountain bristlecone pine located in central Colorado has been dated to be 2,435 years old, according to the OldList, a database of ancient trees maintained by Rocky Mountain Tree-Ring Research, a Fort Collins-based nonprofit research organization. When asked about how to reconcile such disparities at a public briefing hosted by the U.S. Department of Agriculture, Linda Heath, director of inventory, monitoring, and research of assessment for the US Forest Service, suggested that the definition could talk about age, size, or species types as concepts, without going into much detail.

“Old-growth” actually originated as a concept in the 1940s. Then it meant slower-growing, older forests and those with larger-diameter living trees. Since the 1980s, however, the US Forest Service has used a broad definition that speaks of “structural attributes,” including tree size; accumulation of dead woody material; a layered canopy; species present; and ecosystem function. “The problem with [the current definition] is that it’s so generic that it doesn’t really allow you to distinguish between what would be considered old growth or what wouldn’t be,” says Gregory Aplet, Denver-based senior science director for the Wilderness Society, in Washington, DC, a nonprofit that campaigns for land conservation. And, generic or not, Aplet says the old growth has “never been quantified, let alone mapped, for Colorado.”

Redesigning mature forests, some say, could really be beneficial in the Centennial State. What counts as mature? It’s not entirely clear either, but in general, mature forests don’t yet host the decadent tumble of trees and layered canopy that might be recognized as old-growth forests, but they might one day. Some experts recommend drawing the line for mature simply based on the age of the tree; others suggest using biomass, such as woody debris or felled trees, as a delineator. (Ask a lumber industry professional, and “mature” is the age at which it makes sense to turn a tree into lumber.)

Conservation groups in Colorado see Biden’s executive order as an opportunity to extend protections — primarily from accidental losses to roads and wildfire mitigation projects — to mature forests for the first time. For example, if some forests are defined as mature, fire mitigation teams could be asked to leave certain groups of trees intact or prioritize protecting larger trees while reducing risk to nearby communities. . Reversing old-growth forest losses and increasing the harvest of large, old Colorado trees — which pull more carbon dioxide from the atmosphere and can store it for their centuries-long lives — starts with preserving these mature forests. .

“If we cut down all the trees before they’re 80 or 100 years old, we’re never going to sprout any old growth again,” says Ellen Montgomery, public lands campaign director for Environment America, a network of 30 state environmental groups. who argues for the new definition of maturity to draw the line at 80. Montgomery, who lives in Colorado, adds: “The situation we find ourselves in now is that, although a lot of it is protected, we are losing the old growth. It’s kind of chipped. So the idea here is to protect old growth and standby forests.

But the new definitions are only a first step in the process. “I don’t think the existence of a definition by itself makes any difference – it’s what you make of it,” says Aplet.

This would mean that policies would have to be developed, either at the federal level or at the local level, once the definitions were established. Forest Service and Bureau of Land Management land managers, for example, could use these new definitions to revise their management plans and redefine their priorities. But these plans are only updated about every ten years and can take years to complete. Other strategies might include establishing tree sanctuaries or restricting tree cutting, perhaps through administrative action, state policy, or federal legislation. Or it might do nothing at all. After all, the president’s order ends with an inventory; it does not say what to do with this inventory.

Perhaps raising awareness will at least steer mature and ancient forests towards better protections. In Colorado now, Rempel says, threats don’t mean chainsaws and logging so much as insect outbreaks, disease, wildfires and drought. Shortly after being found by tall tree hunters, some of these record-breaking specimens were lost in the 416 fire in 2018. A drop of airborne water on these San Juan behemoths could have saved them – so may -be once forest managers know where the oldest and most important trees are (and policies are more supportive of their preservation), they can take steps to help more survive, even if climate change makes conservation more difficult. germination and growth of trees.

“How can it not help,” Rempel says, “if they really enforce it?”