Ecological Provinces of Oregon


Oregon can be readily divided into two distinctly different regions: the humid maritime climatic area facing the Pacific Ocean west of the Cascade high mountain range, and the more xeric and sparsely populated 3/4th of the state lying in the rain shadow to the east of the Cascades. Each of these regions contains several distinct Ecological Provinces, each with its own characteristic combination of geologic history and ecological sites.  Ecological sites are sufficiently dependable and descriptive to provide a basic unit for managing natural resources at an individual  location. Understanding how these individual sites relate to each other at the watershed or landscape scale is fundamental to effectively managing larger units of land.

Climate types of Planet Earth.


Weather is of great interest to any one who spends time outdoors. It is also a topic of much interest to biologists and ecologists because it helps to explain and predict the structure of biotic communities. All organisms must operate within their physical environment, of which, weather is an important part. Vegetation types often map closely with climate types, allowing one to infer climate from vegetation and vice versa. The climate profile of an area is our way of expressing average weather present over long periods of time. The most commonly used climate classification system is Koppen's, which uses seasonal average precipitation and temperature patterns to group climates into 5 major groups....

The Sky Above - Global Air Circulation. 


....The earth has a heat problem. More sunlight (energy) falls at the equator each day than at the higher latitudes. In fact, the average daily energy striking Oregon (44oN latitude) on the hottest summer day of the year is about equal to an average day at the equator. Luckily, energy tends to flow from hot areas to colder areas by convection. The temperature difference between the equator and the poles fuels Planet Earth's air and water circulation. Warm air rising at the equator is replaced by cooler air draining  off of higher latitudes (Figure1). This air flow forms a circle of rising air at the equator and a corresponding downward  column of descending air forming the subtropical high pressure zone (Figure2) at around 20 to 30O latitude. A second cell redistributes cold dense air from the poles southward. Although air is trying to travel directly from high to low pressure zones, the earth is rotating under it, giving the impression to those of us seeing it from a fixed point on the earth in the Northern Hemisphere, that air is flowing in a clockwise motion away from high pressure and in a counter clockwise motion towards low pressure cells. This produces the characteristic seasonal zonal winds that are seen on Planet Earth at different latitudes. Because winds redistribute moisture as well as energy, zonal precipitation patterns follow air global circulation patterns with areas of rising air getting precipitation and areas of descending air having relatively little precipitation. Surface winds interact with mountain ranges to produce the world's major climatic zones (Figure 3) with their corresponding vegetation zones (Figure 4). 

Survival in the Great Out-of-Doors.


As our society becomes increasingly urban, people venturing out into the countryside for work or pleasure have become increasingly vulnerable to the inconveniences and downright hazards that nature provides for the unknowing or the careless.  This article offers some simple and practice advice about how to make your field experience safe and pleasurable.

About DoctorRange

Dr. Sharrow's pictureDr. Sharrow is Professor of Rangeland Ecology and Management at Oregon State University, USA, where he has taught undergraduate and graduate level natural resources classes for the past 31 years.

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