Forest Ecology

What is forest ecology? Study of –Relationships between organisms and their environments –Interactions of organisms with one another –Patterns and causes of abundance and distribution of organisms in forests What forest ecology is not From Gurevitch et al. 2006

Organisms and Their Environment Climate – temperature, precipitation, etc. Climate – temperature, precipitation, etc. –Note the importance of how these variables are measured and expressed Soils Soils Light Light Interactions and combinations Interactions and combinations Niche – the range of conditions in which a species can survive; i.e., where a species’ traits allow it to successfully interact with its environment Niche – the range of conditions in which a species can survive; i.e., where a species’ traits allow it to successfully interact with its environment

Examples of Niche Sugar maple Sugar maple Jack pine Jack pine Larch Larch

Sugar Maple

Jack Pine

Larch

If there aren’t enough resources to meet the optimum amount for each individual, competition will occur, resulting in If there aren’t enough resources to meet the optimum amount for each individual, competition will occur, resulting in –Reduced growth rate for one or both or –Mortality to one of the competitors In many situations, the species will have developed ways to minimize competition, such as In many situations, the species will have developed ways to minimize competition, such as –Get their nutrients and water from different depths in the soils –Flower at different times relative to leaf development What happens when niches overlap?

Trillium Trilliums flower early, before the hardwood trees above them leaf out – thus giving them time to flower before it is too shaded

Forest Communities/Ecosystems All the species of plants and animals interacting with –One another and –Their environments Examples

Spruce-Fir

Northern Hardwoods

Forest Changes Disturbance and Succession –Forests are always changing due to Disturbances Plant growth and mortality –Examples of disturbances –“Recovery” after disturbances

Examples of Disturbance - Fire

Examples of Disturbance - Wind

Disturbance Example - Harvesting

Succession Changes in species composition, structure, and processes following a disturbance Those changes will be driven by the environment and biota Harvard Forest dioramas illustrate a typical sequence of land changes from clearing during settlement to land abandonment when agriculture in New England went down hill (for multiple reasons)

Harvard Forest Dioramas Harvard Forest dioramas illustrate a typical sequence of land changes from clearing during settlement to land abandonment when agriculture in New England went down hill (for multiple reasons)

Presettlement Forests

Early Land Clearing

Height of Cultivation

Land Abandonment

Harvest of Old-Field White Pine

Hardwoods Follow Pine Harvest

Hardwoods Reach Cordwood Size

Old-Field Succession