Editor's note: The following article on funding public lands, including the National Park System, was written by Margaret Walls, Research Director and Senior Fellow at Resources for the Future, "an independent, nonpartisan organization that conducts rigorous economic research and analysis." It is republished here with her permission.

As the National Park Service’s 100th anniversary draws near, I’ve been looking back at a pair of 2009 reports on America’s “great outdoors.” An RFF report that I coauthored reviewed the status of public lands, demand for outdoor recreation, and conservation funding trends. The study was in support of the Outdoor Resources Review Group, a 17-member bipartisan commission comprising conservation, public lands, and parks experts. U.S. Sens. Lamar Alexander (R-TN) and Jeff Bingaman (D-NM) were honorary co-chairs, and the commission was created by two long-time elder statesmen in the field, noted environmental lawyer Henry Diamond and Conservation Fund Chair Emeritus Patrick Noonan. The commission released its own report (published by RFF) with a set of recommendations, many of which formed the basis for President Obama’s America’s Great Outdoors initiative, launched in April 2010.

Although the two reports are now seven years old, many of the findings still resonate. Here’s a brief summary—some food for thought as we approach the summer outdoor recreation season.

On the demand and supply of outdoor recreation resources:

* The United States is blessed with stunning scenery, diverse landscapes, and a large amount of open space. However, federally owned lands are disproportionately in the West, while urban areas, which are growing, often suffer from a lack of parks and open space relative to their populations.

* Public lands face a series of threats: conflicts, especially in the West, over uses of the lands; inadequate operations and maintenance budgets; aging infrastructure; new management concerns, such as invasive species; and serious problems related to climate change (sea level rise, drought, and wildfires, to name a few).

* Changing demographics, including an aging population, more racial and ethnic diversity, and increasing urbanization, are altering the demand for outdoor recreation and will continue to do so in the future. Public lands agencies are having trouble keeping up with these changing needs and interests.

* The latest generation of Americans may be losing its connection to the outdoors. Children spend less time on outdoor physical activity and especially in natural settings than in the past.

On funding for conservation and outdoor recreation:

* Federal spending on conservation is not trivial—in the RFF report, we note more than 30 programs totaling $6 billion in 2008. But most of these programs are not focused on outdoor recreation. Many of them pay for easements or other restrictions on private lands. Case in point: over one-third of the spending in 2008 was on the Department of Agriculture’s Conservation Reserve Program, which pays farmers to set aside acreage from production.

* The Land and Water Conservation Fund (LWCF), the primary source of funding since 1965 for federal land acquisitions (such as national parks) and for grants to state and local governments, has declined in importance. Offshore oil and gas lease revenues provide dedicated funding at $900 million per year, but Congress has consistently appropriated far less than this. The state grants program has dwindled to a level that makes it irrelevant in many states.

* Several states have filled this funding gap with programs of their own. We identified 79 individual programs in 43 states—financed with lottery revenues, sales and real estate taxes, and other dedicated revenues—totaling $3.3 billion per year. Over half of these programs were initiated in the 1990s and 2000s.

* Private conservation has also grown dramatically in the last few decades with the rise of national organizations such as The Nature Conservancy and thousands of local land trusts. Conservation tax incentives have helped to spur this movement.

* Park operations and maintenance budgets are inadequate. This is true at the federal, state, and local levels, but we found it to be particularly true for states and localities.

What’s happened in the seven years since these reports were published? The recession, which was just hitting the U.S. economy as the reports were completed, had a devastating effect on state and local government budgets. In many states, the first agencies to see cuts were parks and natural resources agencies. State parks saw huge budget cuts and many of them have not fully recovered.

The same is true of the federal land management agencies. The National Park Service’s deferred maintenance backlog has ballooned to nearly $12 billion. The state conservation programs funded by dedicated revenue sources were hit hard and legislatures in many states diverted what money there was to other programs. Some of those programs are starting to recover but some of the diversions have remained in place. The LWCF Act came up for reauthorization in October 2015 and, after much debate, was renewed for only three years. While the LWCF maintains some bipartisan support in Congress, a minority group of conservative lawmakers wants to stop funding land acquisitions altogether and sell off federal lands to the states. These disputes continue, leaving the LWCF—and support for land conservation more broadly—in limbo.

All of this means we’re a long way from adopting the primary recommendation put forward by the Outdoor Resources Review Group in the commission’s report: Establishing a new, independent trust operating outside of the confines of the congressional appropriations process, with $3.2 billion of dedicated annual LWCF funding (an amount equal to the $900 million authorized in the 1970s adjusted for inflation) serving as base support.

Both of these reports stand the test of time. The RFF report and the numerous background studies that RFF researchers undertook or oversaw are a treasure trove of information about our country’s outdoor resources. If you’re interested in learning more, all of these publications can be found on the RFF project page.