MOUNTAIN-CLIMBING TREES

Global warming is leaving trees behind. Some two thirds of forest species in six French mountain ranges have moved at least 18.5 meters higher on the mountainsides per decade during the 20th century. Previous research has demonstrated that plants at the highest elevations on mountains and in the polar regions have shifted to adjust to global warming. The latest result marks the first confirmation that entire ecosystems in lower, more temperate regions are moving as well. The study is in the June 27 Science. —David Biello

LOCATION INFLUENCES VOTERS

The voting location may tip the balance on some election issues. Researchers examined the 2000 Arizona general election that included a proposed tax increase to support school initiatives. After controlling for political preferences and zip codes, the researchers found that voters casting ballots at schools tended to support the measure (63.6 percent in favor) more so than those at nonschool booths (56.3 percent). A follow-up experiment revealed that voters could be subconsciously “primed” with images of lockers and classrooms to vote for a hypothetical tax for school spending. The July 1 Proceedings of the National Academy of Sciences USA contains the findings. —Philip Yam

MARTIAN HIT-AND-RUN

Researchers have long suspected that a massive asteroid caused Mars’s “hemispheric dichotomy”: its crust thins from 50 to 20 kilometers over a south-north span covering 42 percent of its surface. Using gravity data and other measurements, scientists have discovered the hidden outline of the impact—in particular, an elliptical mark spanning 10,600 by 8,500 kilometers. Simulations suggest that the asteroid measured 1,600 to 2,700 kilometers wide, moved at about six to 10 kilometers per second, and struck at an angle of 30 to 60 degrees with the ground. —JR Minkel