This week I am working in the paleobotany collections at the Denver Museum of Nature and Science. A good place to work becomes an even better one if one’s visit aligns with the transit of Venus across the sun. I spent the evening at the museum, watching the one immense object hurtle past another even…

The foresummer has arrived, bringing hot and dry conditions to the desert. Despite the adverse conditions, many species are moving through the reproductive stage of their life cycles. Saguaro cacti are in full bloom – the flowers are especially beautiful at dawn and dusk. This year’s weather has been very favorable, with dozens of flowers…

Around the world, what determines the height plants grow to? Some places have trees a hundred meters high, while others are limited to annual plants shorter than a few centimeters. This range of variation is striking, but also important – canopy height helps us predict competition between species, ecosystem carbon and water fluxes, biomass accumulation,…

A forest can quickly reclaim its own after a disturbance. A decade ago, much of Mt. Lemmon was burned in a fire that destroyed nearly all the understorey and much of the canopy. Today, the scar of the fire remains, but evidence of regrowth is easy to find. Here you can see the broken remains…