Field data for exercise on succession

Goal:

The goal of this fieldwork is collect data that will be used later on for an exercise on succession. One question an ecologist has is whether the structure and composition of an ecosystem remains the same or changes through time. To answer this question one must know what is present now and to follow changes through time to explore what changes might be taking place. Ecologists are not simply satisfied with doing this, but would like to predict what changes might take place and then to test their predictions. Thus in determining the structure and composition of an ecosystem, we not only have to know what mature organisms are present, but what immature are present and which of those might take the place of the older ones when they die.

Directions:

To sample the mature vegetation (i.e., trees in this case), carry out point-quarter sampling on your assigned forest. Sample ten points with 10 m inter point distances. Measure dbh by measuring the circumference of the tree at 1.5 m vertical height. Include only trees with a dbh of greater than 10 cm (roughly 31 cm circumference). Only include live trees in your sample.

To sample the young vegetation use the quadrat techniques with 10 quadrats, each being 10 m^2. Use the table of random numbers to move between plots. You can easily construct a 10 m^2 quadrat by reeling out 12.6 m of tape from the tape measure and holding the corners (sides will be 3.16 m long). Count only trees less than 2 cm dbh. Record in your log book species, dbh, and approximate heights. Only count living trees. Notice that if a sapling is not greater than 1.5 m high, you will not be counting or measuring it. Keep a separate count of saplings that are less than 1.5 m high. In that count you only need note species.

Calculations (for now):

For mature and the two categories of immature vegetation calculate absolute densities (#s / ha). Also calculate importance values. Note that for the less than 1.5 m high saplings, the importance value will only be calculated based on relative density and relative abundance. Keep all the data and the calculated values for a later lab on succession.