Missing the Forest for the Trees

We generally think of trees as an asset: They help sequester carbon, prevent erosion, retain a significant amount of stormwater in the tree canopy if there are enough of them, and, in urban areas, can help reduce the heat island effect. Besides, they’re pretty; green spaces can even help increase the value of nearby real estate. Deforestation, which is happening in many parts of the world due to logging, farming, and urban development, can be devastating to local environments and economies. Even so, it seems not everyone is as enthusiastic about trees as you might expect.

This Economist article reports that forested area is increasing throughout most of Europe, and the rapidly growing young forests are adding more volume of wood every day than the entire volume of iron contained in the Eiffel Tower—more than a million cubic meters of wood each day. The percentage of forested land is also increasing in the US and Australia. Environmental regulations and subsidies for planting trees have encouraged this growth in many countries. Even those countries that are falling behind in their tree-planting goals, such as Iceland, are making strenuous efforts to increase their forests.

More efficient farming methods have been responsible, in part, for the expansion of the forests; as some farmland becomes more productive, it simply isn’t economically viable to keep eking out crops on the less-productive land, allowing many of those areas to be returned to forest.

Ireland, which was just 1% forested at the time of its independence in the 1920s, is now about 11% forested and should be 18% covered with trees by 2046, according to government targets. But some farmers argue that newly forested areas are driving them off their land and reducing property values, and others say the types of trees planted—especially Sitka spruce imported from North America—are disrupting the local habitat. The trees are more hospitable to insects than agricultural crops are, and more insects bring more birds—but the birds the new trees attract tend to be crows, which drive out other native species.

In Spain and Portugal, where the percentage of forested land is also rapidly expanding, critics say that poorly managed eucalyptus plantations are contributing to devastating forest fires. If they were better managed, the counter-argument goes, with the underbrush cleared out regularly, this would be less of a problem, but as it is, the imported eucalyptus contributed to fires in those two countries that caused more than 100 deaths last year.

Some countries have had more success. In Israel, for example, decades of afforestation and reforestation efforts—and numerous changes along the way in what is being planted, based on desired land use, survival rates, and susceptibility of some tree species to pests—have resulted in a “near-native” ecosystem, as this article describes. In the last 30 years, the country has particularly pursued diversity, in both the range of species and the ages of the trees in a given area: “a transformation from pure, even-aged forests to a mosaic of mixed, uneven-aged, multiple-use forests, with a greater degree of ecological stability, biological diversity, and landscape aesthetic value.”