"Perserve, Protect, Enhance and Educate"

Botanical Society of ZooMontana

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"Climate of the Arboretum"

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. See our Billings climate information on the Garden Weather page. 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. That is one facet of the "Plant Select" program.


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 [source: USGS].


courtesy of Wikipedia

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.