top of page

courtesy of Billings WeatherCast


Climate is simply weather statistics averaged over a 30-year span which gives us a good idea of what weather to expect at particular times of the year. Here in the Billings area we are used to the climatic conditions that affect our trees with precipitation, heat and cold, humidity and resulting soil conditions. The Arboretum at ZooMontana experiences what's known as "microclimate"(see below). Each tree is exposed to weather and terrain in a different way. For example, the Sensory garden, and it's trees, is a berm garden 6 feet deep, surrounded by mature trees and because of the grassy areas and water features it traps moisture  and retains heat in a compact environment. 

In contrast about 100 feet away and at a higher elevation is Dottie's Garden. This garden and it's trees is much more exposed both to warm sunshine and wind resulting in a completely different microclimate from the Sensory garden. As a result, it is best suited to "water-wise" trees, plants and xeriscaping. As part of the educational process the Botanical Society at the zoo experiments with different plants, trees and flowers in each garden microclimate to determine what works best for Billings gardeners. 


courtesy of How Stuff Works

Trees affect our climate, and therefore our weather, in three primary ways: they lower temperatures, reduce energy usage and reduce or remove air pollutants. Each part of the tree contributes to climate control, from leaves to roots.
Leaves help turn down the thermostat. They cool the air through a process called evapotranspiration. Evapotranspiration is the combination of two simultaneous processes: evaporation and transpiration, both of which release moisture into the air. During evaporation, water is converted from liquid to vapor and evaporates from soil, lakes, rivers and even pavement. During transpiration, water that was drawn up through the soil by the roots evaporates from the leaves. It may seem like an invisible process to our eyes, but a large oak tree is capable of transpiring 40,000 gallons of water into the atmosphere during one year. 


courtesy of Wikipedia


A microclimate is a local set of atmospheric conditions that differ from those in the surrounding areas. Because climate is a statistic, which implies spatial and temporal variation of the mean values of the describing parameters, it is clear that within a region could occur and persist in time, sets of statiscally distinct conditions, i.e., microclimates. The term may refer to areas as small as a few square meters or square feet (for example a garden bed) or as large as many square kilometers or square miles.
Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavy urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and re-radiate that heat to the ambient air: the resulting urban heat island is a kind of microclimate. Microclimates can be found in most places. Another place this can occur is when the ground is made of tar or concrete; because these are man-made objects, they do not take in much heat, but mainly reradiate it.


Yellowstone Arboretum Initiative

In early 2019 the Yellowstone Arboretum is planning a climate monitoring program to determine the benefits of microclimates on existing and future species. The program will consist of monitoring stations set up at strategic locations throughout the arboretum to record weather trends and the effect it will have on trees within those locations. Each station will have instrumentation to record temperature, humidity, rainfall and wind. At the time of observations those statistics will be compared to current readings as reported by the National Weather Service. Determinations will be calculated to record variations in temperature and humidity and wind direction trends. Those determinations will aid arboretum staff to calculate the correct planting of future species and the maintenance of trees located in close proximity of the instrumentation stations.

New locations coming in 2024

bottom of page