L10. Forest Trends
Welcome to Unit 3 of the course! This unit is all about our most extensively used biorenewable resource in the United States - Wood! Over the next series of lessons you will learn about the status & trends of our forest resources, properties of wood that affect the products we make, forest certification, and more! At the end of this unit you will have an understanding of the processes that go into making forest products, and you will be able to compare the environmental impacts of forest products with those of non-renewable materials.
History of forest resource use
To get started, we have an interesting video from the Bell Museum that details the decimation of Minnesota's forests as people began moving to the state and settling the frontier. After the first land survey in 1848, loggers in Minnesota had free range over the forests for roughly 50 years, and the consequences were devastating.
The Great Hinckley Fire of 1894 inspired a movement to implement forestry regulations. A major turning point came in 1933, when President Franklin Delano Roosevelt created the Civilian Conservation Corps (CCC) to put young men to work during the Great Depression. Over the 9 years that the CCC was active in Minnesota, the men cut and cleared brush to help conserve existing forests and planted 123,607,000 trees. Their efforts helped to revitalize the state's ravaged timberlands.
Today's Forests
As of 2012, forests cover 73% of the land area that was originally forested at the time of European settlement. The United States has 751 million acres of forestland, of which 514 million acres are classified as timberland (Bratkovich, 2012). Note that Forestland is the large category. Things like Timberland, Plantations, Reserved Forestland, etc. are all part of Forestland.
- Forestland - Land at least 120 ft wide and 1 acre in size with at least 10% cover (or equivalent stocking) by live trees of any size, including land that formerly had such tree cover and that will be naturally or artificially regenerated.
- Timberland - Forestland that is producing, or is capable of producing, in excess of 20 cubic ft per acre per year of industrial wood and not withdrawn from timber utilization by statute or administrative regulation.
- Reserved Forestland - Forestland withdrawn from timber utilization through statue, adminsitrative regulation or designation without regard to productive status.
- Other Forests - Forestland that is rated low for wood volume or growth potential.
Table 1. Forest and timberland in the United States
| Type of land | United States | Contiguous U.S. |
| Total land | 2.3 billion acres | 1.9 billion acres |
| Forestland | 751 million acres | 623 million acres |
| Timberland | 514 million acres | 475 million acres |
| Reserved Forestland | 75 million acres | - |
| Other | 162 million acres | - |
Doing some quick math, that means that about 1/3 of the land in the U.S. is covered by forests! Note: this isn't that impressive; there are many countries with a far higher percent of their land covered by forests for example: Suriname (90%), Gabon (85%), Mozambique (78%), etc.
These forested acres supply the 154 million dry tons of forest resources that we use every year in the U.S., which is more than the usage (by weight) than all metals and all plastics combined. It may sound like we're still plundering our forests - but the way we manage them has changed dramatically since the 1800's. Foresters today have a much greater understanding of the natural processes that go on in forests, and an appreciation of the value they provide. In the following video, Katie Fernholz explains how sustainable forestry works, and how foresters make informed management decisions.
If interested, here is that big book (Silvics in North America Links to an external site.) that Katie was talking about. Pretty impressive!
Thanks to sustainable forest management, we are able to meet society's demand for forest products without losing vast quantities of forestland. On the contrary, forestland in the U.S. is actually increasingly slightly every year.
An example of forest renewability is provided by the 60-year-period ending in 2010, during which over 847 billion cubic feet of timber were harvested from U.S. forests, a volume approximately equivalent to a bulk pile of wood (no spaces) measuring 1 mile x 1 mile x 5.75 miles in height! This wood was used in building some 90 million homes and in producing countless other products. And what was the impact on domestic forests? Because forests are renewable, the volume of of wood within domestic forests increased by more than 50 percent during those 60 years. (The Irresponsible Pursuit of Paradise, Chap 8)
In the following video, Jeff Howe gives an overview of some of the trends we are seeing in our forest resources, both in the United States and globally.
At the end of the video, Dr. Howe says "When the forests are valuable, we tend to have forests." He tried to explain it with a story of apples and bananas, but I am not sure if you made the connection.
The reason that our forest resources are increasing is because we use the wood that is being grown. Forests are a business (we will discuss forest ownership below) and the economics of growing and harvesting of trees is based on supply and demand. Land owners will choose to grow trees only if growing trees is profitable. If not, they will convert their land to some other business. This is like any other agricultural crop (e.g. apples or bananas). Farmers will grow what is needed and what is profitable.
This concept is also an important driver for sustainable forest management. If a landowner is in the business of growing trees they will manage their forest to be healthy and productive. Certainly this is not always the case, but in general this is why we continue to expand our forest resources.
Regional Variation & Ownership
Forest distribution varies greatly across the country. Forests dominate the Eastern U.S., northern Minnesota, Wisconsin, and Michigan, and the Pacific Northwest, but are largely absent from the Great Plains/Corn Belt region of the United States. If you remember from lesson 7, this is due primarily to rainfall, temperature, and soil type. Unlike annual crops where there is a lot of human intervention (irrigation, fertilizers, plant breeding, etc.), forests grow where nature suites them. We can't really pick and choose where trees grow. This means deforestation and development in forest areas is really an important topic. Once the trees are gone and the land turned in to agricultural crops or houses, that forest area is lost.
Figure 1. Map of forestland distribution in the United States.
This regional variation also means that the reported national trends in forest growth do not apply to individual regions.
“Although forest area is up slightly on a nationwide basis (1953–2007), total forest area trends vary by region. For example, since 1953, the forest area in the South and Pacific Coast regions are down by 5 and 4 percent, respectively, due largely to urban expansion and development encroaching into forested areas. However, increases in forest area have occurred in the North (7 percent) and Rocky Mountain (6 percent) regions.” (Bratkovich, 2012)
Ownership
It is a common misconception that the state and federal government own most of the forests. That is not true. In fact, only about 37% of forests are on government land (state, federal or local). Interesting also is that there are regional differences in ownership. Most of the forests of the Eastern U.S. are privately owned by families and corporations, while the majority of western forests are federally owned (Figure 2).
Figure 2. Map of forest ownership in the United States.
The image on the right is a blown-up version of the pie chart in the corner of Figure 2.
Why Ownership is Important
Different owners mean that the land is managed to meet different objectives. Public forests are managed (in theory) for the public good, with an increasing emphasis placed on non-wood uses like recreation and maintaining fish and wildlife habitat. This results in increased harvesting on private lands, with private corporate owners managing their land primarily for wood production. Private non-corporate owners approach management in a range of ways, from intensive wood production, to natural forests that are not used for either wood production or recreation.
Unlike many other countries, forest management rules that are mandatory in U.S. public forests do not apply to private forests. Forest management in private forests, especially in the southern U.S., is very lightly regulated compared to the rest of the world (Siry et al. 2010).
Future of Forests
It also wouldn’t be fair to conclude this lesson without discussing some of the concerns related to forest resources in the United States. Here are some additional experts from the Dovetail report by Brakovitch (2012)
Loss of Working Forests (including fragmentation)
Land with trees provides society with numerous benefits including ecosystem services such as filtration of rainwater, habitat for wildlife and pollinating insects, and scenic beauty... Today, forest tracts are smaller than earlier in our history... When forests become fragmented, neglected, or are converted to other land uses the level of ecosystem services, as well as wood and non-wood forest products, often declines. One paradox we are faced with is relatively stable forest area in the U.S. but a decline in the area of working forests that are being managed to provide diverse ecosystem services. When the area of working forests decline, the pressure on other forests to provide these services is increased and can create challenges for sustainability.
Forest Health and Disturbances
[...] total mortality of trees in the U.S. amounted to nearly 7.8 billion cubic feet in 2006, marking the highest level of volume loss recorded to date. In addition to increasing age, wildfire plus insects and diseases are the main factors impacting forest health.
[...] For 10 years (1997 through 2006), the area annually impacted by wildfire averaged about 6 million acres across the U.S. However, between 2004 and 2006 the average was over 8 million acres per year, and there has been an increase in the incidence of severe fire events. [...] The incidence of insect-induced tree mortality has increased three-fold in the past decade.
The Bottom Line
We have a paradox regarding U.S. forests. As a nation, our forest area is stable, growth exceeds harvest, volumes of growing stock are up substantially, and wilderness and other reserved forests has tripled in size over the past six decades. At the same time, specific regions of the country have experienced declines in forest area, timber land area, and growing stock volumes on timber land, and have significant forest health issues that threaten large swaths of forests. The bottom line is that both national and regional (local) perspectives are critical when evaluating the status of, and sustainable outlook for, our forests. Ignoring either perspective can lead to incomplete and erroneous conclusions.
References:
Brakovitch S., et al 2012. Forests of the US: Understanding Trends and Challenges. Download Forests of the US: Understanding Trends and Challenges. (Dovetail Partners Report)
Bowyer. J., 2016. The Irresponsible Pursuit of Paradise.