First resurvey of the Lehigh Experimental Forest

Growth, mortality, and recruitment (shown in red) of dominant tree species in the Lehigh Experimental Forest from 2013-2015. Average tree size and numbers of indivduals included in the survey shown in blue. We will use these data as a springboard for discussion of processes controlling forest dynamics.

Growth, mortality, and recruitment (shown in red) of dominant tree species in the Lehigh Experimental Forest from 2013-2015. Average tree size and numbers of indivduals included in the survey shown in blue.

Inventory of the forest.

Taking inventory of the forest, 2015.

Students in general ecology (EES-152) resurveyed a portion of the Lehigh Experimental Forest, to assess changes in tree growth, mortality, and recruitment since 2013.  No new trees greater than 1.4 m high were documented, and both growth and mortality varied considerably among species.  Over 500 trees were measured, and the plot above shows data for the dominant trees (those with >15 individuals included in the survey).

We will use these data as a springboard for discussion of processes controlling forest dynamics, and will examine some of these issues in greater depth during our discussions and future lab activities.

 

For now, students should answer the following questions:

1. The dbh measurements were converted into estimates of area, assuming that each tree was a perfect circle in cross-section. Why do you think basal area was used to compare growth among the different species? Why was this expressed as the average change in basal area per tree, as opposed to the total change in basal area for all individuals of the species? What factors might have caused the observed differences in radial growth among species?

2.  What does the pattern of mortality and recruitment suggest about the future of the Lehigh Experimental Forest? What factors might have caused the differences in mortality among species during these two years? What factors might be contributing to the lack of new tree recruitment in the forest?

3.  Which species had both very high mortality and very low growth during this time period? Do some research on current threats to this particular species, and summarize your research in a short paragraph.

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Posted on September 17, 2015, in Ecology (EES-152) and tagged , , , , , . Bookmark the permalink. Leave a comment.

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