What should we call farm land at the end of the fall harvesting season? Silly question, right? Just because the land is void of vegetation in the winter does not mean that it is something less than farm land; unless, that is, you work for the U.S. Geological Survey. If that is the case, then what had been a farm is “defarmed” after harvest. It is a brown, barren, and scarred wasteland. At least that is the logic being proposed by M Drummond and T Loveland (great name for an environmentalist) in Eastern U.S. Forests Resume Decline, which was printed in Science Daily.
In this study, once forest land is harvested, Drummond and Loveland remove it from the category of “forest lands”, and put it in a category with the title of “mechanically disturbed”. Even though trees begin to grow back immediately after harvest, and these lands are still set aside for growing trees, the authors remove the “forest” label.
This makes no sense at all. By this definition, forests destroyed by fire, disease, and infestation are no longer forests. How tall do the replanted trees have to be before they qualify as “forests” again? Returning to the farm land analogy, based on this way of thinking, the U.S. and Canada have no farm land between November and April each year – except in the warm weather climates.
Second Thoughts – This post was initially written based on a synopsis covered in Science Daily and it was planned for posting last Friday. Then it occurred to me that the Science Daily synopsis seemed ridiculous. Maybe the wording in the synopsis just made it appear as if the authors of the study were counting harvested forest land as something other than forest land. Maybe the post being planned would misrepresent their work. So the post was held until the original 13 page report that was published in BioScience, could be reviewed. (Available here for the rest of April)
It turns out that the post could have been published on Friday without doing injustice to the fidelity of the study. As the study is reviewed below, keep in mind that the study designers do a lot of estimating, and the authors had a vested interest in the outcome, so we should be skeptical of the data. Nevertheless, even if we assume the data is accurate, the conclusions the authors draw misrepresent the data.
Study Conclusion – The authors conclude that between 1973 and 2000 forest cover in the eastern U.S. declined from 54.7% to 52.4%, a total decline of 4.1% over the 27 year period. According to the report, a total of 3.70 million hectares of forest cover was lost. (See table on page 292 for a list of various changes in land use)
It turns out, however, that if we consider harvested forest lands as forests, as any reasonable person would, then the entire loss of forest cover during the 27 -year period is no more than .50 million hectares. (Even this loss is questionable. The authors show 1.27 million hectares moving from “mechanically disturbed” to shrub land. This is unlikely. Forest land that has been harvested of trees, and has proven economic value as a forest, will not sit idle as shrub land. This is probably just another in-between and temporary category).
The designers of the study were only able to arrive at the inflated number (3.70 million acres of forest land lost) by manipulating the data. As mentioned above, harvested forests were no longer considered forests…until some period of time passed. At some point the study designers add these “mechanically disturbed” lands back into the category of forests. However, and this is the key, they concluded that (over the 27-year period) more land (3.2 million hectares more) went from forests to mechanically disturbed than moved from mechanically disturbed to forests.
The authors are clear in how they arrive at forest cover data. Note the following passages from the study.
The net loss occurred even though reforestation of abandoned fields and pastures continues, in some regions more than others. Most net forest loss occurs as result of mechanical disturbance of forests for timber production, which keeps some land free of forest, and as a result of urban expansion, which is generally a permanent change…
The authors acknowledge the short-lived ephemeral nature of site-specific disturbances…ie tree harvesting. They even go on to point out that the reason more trees were harvested during the 1973-2000 study period than in years previous to the study period is simply due to the surge of timber plantations in the southeast during the ‘50s and ‘60s. Southern pines can be harvested in 20 years or so. Therefore, as these plantation pines grew to maturity and were harvested, more forest land was being harvested (mechanically disturbed) than had been the case prior to establishing these plantations.
Stated differently, there is no intimation that forests are being harvested in a non-sustainable manner.
Discussion – Let’s just logically review the forestry big picture in the east. When most Americans were farmers and were migrating west across the country, forests were cut down along the way to build homes, etc, but mostly for farming. When farming jobs were replaced during the industrial revolution, the less efficient farm lands (particularly in the northeast) were abandoned. Forests have been regenerating naturally for at least the last 100 years. (By the way, this type of migration, and conversion of forests to farmland is the reason for deforestation in the Amazon.)
Forest regeneration slows over time, of course, and at some point the process will be complete. As regeneration is slowing, expansion of urban areas is consuming more forest land. It is possible that the writers of this report are correct in that sense. Perhaps total forest area in the east is declining slightly. If not now, it will certainly happen in the future. But the fact that urban expansion is absorbing some forest land is not something to panic over.
In this report, the authors suggest that 1.91 million hectares moved from forest land to urban “developed” over that 27 year period. Moving in the other direction, however, 3.39 million hectares were changed to forests – from farm land and shrub land.
One more point. Why did the study period stop at 2000 rather than 2009 or 2008 or whenever the latest data was available? My guess is that the trend of reduced forest cover (as measured in this report) began to reverse itself. Remember, once equilibrium (sustainability) is reached with those new plantations from the ‘50s and ‘60s, the negative trend in forest cover stops.
Summary – This study actually demonstrates that the land set aside for forests in the eastern U.S. was little changed during the study period.
Political corruption has always existed in the U.S., but our country has enjoyed relative protection from the kind of institutionalized corruption that is common in many parts of the world – mostly the developing world. Rule of law has been a significant competitive advantage for us.
