Natural disturbances in forest environments

Type :

Presentation

Pages :

7 pages

Format :

.doc

Published date :

11/21/2008

Category :

Political science

Sub category :

Ecology & environment

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Summary :

Introduction.
Small-scale disturbance: gap phase dynamics.
Changes in microclimate and resource availability following gap creation.
Forest regeneration in gaps.
1. The changes in microclimate and resource availability.
2. Photoblastic germination.
3. Germination in gaps.
Importance of chance effects.
Forest growth cycle.
Large-scale disturbances.
1. Disturbances that result in primary succession.
2. Disturbances that result in secondary succession or recovery.
Conclusion.

Abstract

Disturbance in plant communities has been deﬁned as consisting of 'the mechanisms which limit the plant biomass by causing its partial or total destruction.' In forests, disturbance arises from the agencies of tree damage or death. At small spatial scales, individual trees die standing or fall over, but in both cases a gap in the canopy is created and this initiates a successional process known as the forest growth cycle. The agencies of natural disturbance at larger spatial scales include windstorms, ﬁre, and landslides and these factors vary in their impacts on forests and the ensuing mechanisms of forest recovery. natural disturbance regimes in forests are important because they impact on tree population dynamics, the relative abundance of different species and functional groups, the biomass and carbon content of vegetation, and interactions with other components of the biotic community. Community ecologists have highlighted the importance of disturbance among mechanisms proposed for the maintenance of tree species richness, particularly in species-rich tropical forest communities. Small-scale natural disturbances are an inherent component of all plant communities because plants have a ﬁnite lifespan. In forests, the size of the individual tree at the time of its death and the mode of death determine the scale of the disturbance created.