Dynamics of Nutrient Cycling

Adapted from: Peter M. Bierman and Carl J. Rosen. Nutrient Cycling and Maintain Soil Fertility in Fruit and Vegetable Crop Systems. Department of Soil, Water and Climate, University of Minnesota. Available at: http://www.extension.umn.edu/distribution/horticulture/m1193.html#nutcyc


Plants require four factors for growth and reproduction: light, water, the right temperature, and nutrients. Plant nutrients are chemical elements that are mostly absorbed by plant roots as inorganic chemicals dissolved in water, and it is important to understand both the biological and chemical processes that …

Diversity in the Forest Understory

Written by Amy Grotta

The understory of a forest is made up of the trees, shrubs, and herbaceous plants that exist below the canopy. In general, the forest understory makes up the largest percentage of plant diversity in a given forest ecosystem. While the canopy, or overstory, may be composed of one to a dozen tree species, depending on the ecosystem, many more plant species tend to be found in the understory (Table 1).

Table 1. Number of plant species …

Biodiversity in Forests

Written by Amy Grotta

Biodiversity refers to the range of life forms and species that exist within a given ecosystem. Different forest types have varying degrees of biodiversity. Tropical rain forests are some of the most biologically diverse ecosystems on the planet. However, even temperate forests consisting of only a few overstory tree species may contain surprising levels of biodiversity when all other life forms found within them are considered (e.g., herbaceous plants, mammals, birds, invertebrates, fungi, etc.).

Species exist …

Understanding Soils in Forests

Written by Sabrina Kleinman

Soil is an important component of forest and woodland ecosystems as it helps regulate important ecosystem processes, such as nutrient uptake, decomposition, and water availability. Soil also represents one of the largest carbon pools on the planet whose alteration can impact carbon storage and carbon emissions. Soil carbon helps soils retain water, increases soil’s capacity for holding on to important nutrients such as nitrogen and phosphorous, and serves as a source of energy for belowground organisms …

What Makes a Tree Unique?

Written by Peter Kolb, University of Montana

A tree is a plant with a tall structure comprised of a stem and branches to support leaves and a root system than anchors the stem as well as procures and stores essential growth elements, such as water and nutrients. Trees are unique from other plants because they can and usually do live for decades and even up to several millennia (the oldest known single-stem tree is a baobab in South Africa measured …

Microflora and Fauna in Forests

Written by Peter Kolb, Montana State University

Forests (Figure 1) are composed of many trophic levels that include primary producers: large and dominant trees, as well as understory shrubs, forbs, grasses, mosses, lichens, and even algae; large and small herbivores such as moose, deer, mice, and caterpillars; carnivores such as cougars, coyotes, weasels, shrews, and cleride beetles; and decomposers, which could include larger animals such as bears that eat carrion but are usually comprised of smaller organisms such …

Insects in Forests

Written by Peter Kolb, Montana State University

Figure 1. Some common tree-inhabiting beetles including large staghorn beetles (center), roundheaded borers (left), and a variety of much smaller bark beetles (right). Photo courtesy of Peter Kolb, Montana State University.

Insects perform many roles within forests as pollinators, herbivores, carnivores, decomposers, and food sources for other organisms. As a group, they are the most abundant and important group in the phylum Arthropoda, and by 1972 more than 900,000 species had already been …