In these early April days, you have probably noticed that every excursion through The Arb has been accompanied by lots of wind. April is the windiest month in Minnesota, with a daily average wind speed of 11.8 mph. At the forefront of these windy conditions is the volatility and gradient of the temperature. Air moves from a region of high pressure to one of low pressure, the difference caused by unequal heating of the atmosphere. There is still very cold air in the poles and warm air around the equator which leaves Minnesota in a transition zone. 

While walking on the paths in the Arb you may notice the lingering noise of the leafless trees rustling with the breeze. Wind is important for trees in forests, like the restored forest habitat in The Arb. Root systems tend to form more structural root mass when exposed to persistent prevailing winds from one direction. The tree’s adaptive growth in response to wind movement enhances the rigidity of the soil-root plate, helping to counteract the increasing vulnerability to windthrow as it grows taller. Also, wind increases the amount of pollen in the air and the distance tree seeds can be blown. These are of great ecological importance for the perpetuation of the tree species in the Arb. Nearly all conifers (cone bearing seed plants) rely on wind pollination, as do some hardwood trees including oaks (Quercus sp.) and American elms (Ulmus americana sp.). Consistent wind is very important for the trees and plants in the Arb and is representative of the transitional phase we are in, not just in terms of the weather wise, but also as the winterized Arb begins preparing for a green spring.