GLOBAL WARMING:
Tree and Warm Season Grass Plantings Could Make A Difference
William L. Hoover, Professor of Forestry, Purdue University
The continuing debate about global warming has focused on reduction of carbon emissions. This sacrificial approach has generated a strong backlash, especially from the multitudes who view global warming as the mantra of environmental extremists. A popular bumper sticker among our ilk is "Trees Are The Answer." The question this answers could be "can we make greater use of forests to seize carbon dioxide from the atmosphere and protect the planet from climate change." This is a compromise that even those in the "it's a hoax" camp should be able to support.
Because trees serve as nature's "sink"' for vast amounts of carbon, one is amazed at how little attention the United States is giving to the importance of native and plantation forests in the battle against global warming. President Clinton's three-stage plan to reduce accumulations of greenhouse warming gases includes a number of innovative solutions such as "emissions trading." Economists, by-the-way, are very doubtful that trading among countries will work, even though it's very effective within a country. But the plan makes scant mention of the role of trees and permanent grass cover in mitigating the problem. This, despite the fact that scientists estimate that an all-out effort to maintain the health of forests and plant more trees in this country could offset 20 percent to 40 percent of the estimated 6.2 billion tons of U.S. carbon dioxide emissions.
Indeed, there is growing scientific evidence that forests, and the carbon they
sequester, are undervalued. Recent studies have determined that huge amounts of carbon are
stored in peat and other organic matter in soils, now estimated to account for about
two-thirds of the total sequestered. Indeed, more carbon dioxide maybe taken up by native
forests, tree plantations, prairies, and other ecosystems in the United States than is
released by industrial activities, according to a new study by a team of scientists from Columbia University's Lamont-Doherty Earth
Observatory, Princeton University
and the National Oceanic and Atmospheric Administration.
There's evidence that elevated levels of carbon dioxide stimulate tree growth, and therefore carbon storage. Pilot studies at an experimental tree farm run by Duke University in North Carolina have shown that the growth of 15-year-old loblolly pines increased by 11 percent over a year when the trees were exposed to one and a half times the normal atmospheric concentration of carbon dioxide. Thus, southern pine forests could represent a significant weapon in the battle against global warming, if above-normal growth of the loblolly pines continues over a number of years. In addition, acreage of forest cover is increasing in the Midwest as pasture and other old fields revert back to trees. This process could be accelerated by increasing tree planting. Maybe those of us in the hardwood country haven't caught up with the scientific and practical knowledge available for the culture of southern pine, but we've made major gains over the last 20 years and the pace is accelerating.
What's important to recognize is that the United States already has the know-how to increase carbon storage in several ways.
Changing some timber harvest methods should be a high priority. Today, the great majority of forest-product companies in this country practice sustainable forestry, which is designed to maintain and improve long-term forest health and productivity. But the practice needs to be broadened both in this country and abroad.
Because forest soils and tree roots hold much of the carbon, we must assure that tree
cover is quickly restored after harvesting so they can provide canopy cover to shade soil
and prevent erosion. Environmentalist claims not withstanding, commercial logging using
best management practices followed by prompt natural or artificial reforestation actually
increases carbon retention, and thereby helps minimize the greenhouse warming problem. 
There is, however, another reason for promoting sustainable forestry. Unless the United States makes a serious effort to improve the health of its own forests, developing countries can't be expected to impose adequate controls on slash-and-burn clearing to save their forests.
For instance, 44 percent of the original habitats of Indonesia have been converted to other uses, and even larger portions of its lowland tropical rain forests have been linked to slash-and-burn clearing. These some practices are taking a large toll of forest lands in South America, Africa and Southeast Asia. According to the United Nations, the Earth is losing 42 million acres of tropical forests each year - an area greater than the size of Florida. This happens to provide land for subsistence agriculture, a sustainable practice when population levels are low enough to allow adequate fallow periods for forest recovery. Unfortunately, this is not the case.
From a global worming standpoint, tropical forests are the worst kind to lose, since they are able to absorb twice as much carbon per acre as temperature forests owing to their higher rate of photosynthesis. Estimates are that one-quarter to one-third of greenhouse gases result from deforestation.
Because climate change affects us all, there must be an all-out crusade by public and private sectors alike in the United States and abroad to maintain existing forests as large standing reservoirs where carbon is sequestered. Vast areas of Indiana and other states could be returned to forest and prairie cover by tree and warm season grass planting. The worst case scenario is that some of these lands may someday need to be converted back to crop production. In the meantime the tree and grass cover will be building up soil. The organic matter in forest and prairie soils is added faster than it is oxidized. The opposite is true for tilled soils.
We also need to seek ways to satisfy the apparently primal urge to live in the woods without losing the woods we live in. If the septic system problems can be solved an obvious approach is to concentrate houses, leaving more woodland as commons for woodland residents of the two and four legged variety.
An estimated 4 million to 5 million acres of marginal land once used for
farming has been converted to timberland under the Federal
Conservation Reserve Program. But with the appropriate incentive to landowners more
than 100 million acres of marginal land considered biologically suitable for trees - an
area the size of California - could be reforested.
A nationally coordinated program to plant even more trees in cities and suburbs should be undertaken. By shading homes and public buildings, trees reduce the need for air-conditioning, while storing carbon from automobile exhausts and other fossil-fuel combustion. The savings in air conditioning alone from properly situated trees and shrubs is considerable. Just watch out for power lines and plant appropriate species near them.
Together, these efforts could have a major impact on reducing the adverse effects that might come from global worming. Before we agree to carbon taxes that could hobble our economy, we should pursue all possible alternatives that achieve the same result: less carbon dioxide in the atmosphere.
Whether our political leaders are up to the challenge of facing the global warming issue with an approach that benefits us regardless of its severity, those of us who own land can exercise our private property rights and plant trees and warm season grasses to our hearts content. Isn't American great! We don't have to depend on Washington to solve all our problems.