nd 2015. This, in turn, eroded at least five separate benefits provided by trees, the report suggests: Lowering energy costs (through shading), stowing away carbon, pulling pollution out of the air, cutting down on runoff of pollution-laden water during storms and increasing the value of homes.
The research notes that the single most devastating insect invasion, so far, appears to be the Emerald ash borer, a colorful green beetle native to Asia that does exactly what its name sounds like — bores holes in ash trees. It’s now in 27 states, and the ultimate cost could be $ 12.7 billion, the group says — because there are 8 billion ash trees in the U.S. that could be felled. Already, “hundreds of millions” have died, and there’s a particular threat to urban areas, where much ash is planted.
“Ironically, in many neighborhoods, ash trees were planted to replace American elms (Ulmus americana) killed in the mid-20th century by Dutch elm disease, an introduced pathogen vectored by an invasive beetle,” the study says.
All of this should worsen, the research suggests — because invasions appear to be correlated with the growth of international trade. The paper therefore suggests the U.S. must get a great deal more defensive in its outlook toward the massive numbers of imported goods that carry with them a pest risk. The researchers in particular single out live plant imports — which number 3 billion per year — and wooden packing crates and pallets, which insects bore into.
The study suggests going so far as banning wood packing materials entering the U.S. (among other policy possibilities), and strengthening of quarantine measures for live plant importations.
“A lot of the attention is focused on stopping the spread of pests that are already here, but we really need to focus on stopping the next one, not the last one,” Lovett says.