Forest EcologyForest Ecology

What is 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 What forest ecology is notnotFrom Gurevitch et al. 2006

Organisms and Their EnvironmentOrganisms and Their Environment

Climate – temperature, precipitation, etc.Climate – temperature, precipitation, etc.– Note the importance of how these variables are Note the importance of how these variables are

measured and expressedmeasured and expressed

SoilsSoilsLightLightInteractions and combinationsInteractions and combinationsNiche – the range of conditions in which a species Niche – the range of conditions in which a species

can survive; i.e., where a species’ traits allow it to can survive; i.e., where a species’ traits allow it to successfully interact with its environment successfully interact with its environment

Examples of NicheExamples of Niche

Sugar mapleSugar maple

Jack pineJack pine

LarchLarch

Sugar Maple

Jack Pine

Larch

If there aren’t enough resources to meet the If there aren’t enough resources to meet the optimum amount for each individual, optimum amount for each individual, competition will occur, resulting incompetition will occur, resulting in– Reduced growth rate for one or both orReduced growth rate for one or both or– Mortality to one of the competitorsMortality to one of the competitors

In many situations, the species will have In many situations, the species will have developed ways to minimize competition, such developed ways to minimize competition, such as as – Get their nutrients and water from different depths Get their nutrients and water from different depths

in the soilsin the soils– Flower at different times relative to leaf Flower at different times relative to leaf

developmentdevelopment

What happens when niches overlap?What happens when niches overlap?

TrilliumTrillium

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

Forest Communities/EcosystemsForest Communities/Ecosystems

All the species of plants and animals interacting with– One another and

– Their environments

Examples

Spruce-FirSpruce-Fir

Northern HardwoodsNorthern Hardwoods

Forest ChangesForest Changes

Disturbance and Succession– Forests are always changing due to

DisturbancesPlant growth and mortality

– Examples of disturbances

– “Recovery” after disturbances

Examples of Disturbance - FireExamples of Disturbance - Fire

Examples of Disturbance - WindExamples of Disturbance - WindExamples of Disturbance - WindExamples of Disturbance - Wind

Disturbance Example - HarvestingDisturbance Example - Harvesting

SuccessionSuccession

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 DioramasHarvard 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 ForestsPresettlement Forests

1740 - Early Land Clearing1740 - Early Land Clearing

1830 - Height of Cultivation1830 - Height of Cultivation

1850 - Land Abandonment1850 - Land Abandonment

1910 - Harvest of Old-Field 1910 - Harvest of Old-Field White PineWhite Pine

1915 - Hardwoods Follow Pine 1915 - Hardwoods Follow Pine HarvestHarvest

1930 - Hardwoods Reach Cordwood 1930 - Hardwoods Reach Cordwood SizeSize

Old-Field SuccessionOld-Field Succession