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Sycamore growth patterns

David Pope
Science Research Fellow, DePauw University
Summer 2004

I measured the effect of location on growth patterns of sycamore trees in and around the abandoned limestone quarry in the DePauw Nature Park.  Sycamore trees grow in quarries, strip-mined lands, and other stressful habitats. I was interested in measuring the effect of stressful growing conditions on the trees.

I hypothesized that sycamore trees located in the Quarry Bottom would grow more slowly, would have lower live limbs, and would be smaller than sycamore trees in other locations. 

I sampled trees from four locations:  Quarry Bottom, Rim Trail, Creekside Trail, and meadow.  Total height, diameter at breast height (dbh), and lowest live limb height were recorded for each tree. The ages were estimated for a group of trees from each location by counting the rings on tree cores or tree discs.

Sycamore trees on the Rim and Creekside Trails were larger in diameter and taller, and their lowest live limb was higher off the ground compared to trees in the Quarry Bottom and meadow.  Trees in the Quarry Bottom and meadow were shorter and had the lowest live limbs.  Trees in the meadow were taller than trees in the Quarry Bottom.

The differences in growth of sycamore trees among the four locations are due to competition, environmental conditions, and time since disturbance.  Sycamore trees are older and larger on the Creekside and Rim Trails; there has been a longer period of time since disturbance in these two areas.  Sycamore trees in the Quarry Bottom have the lowest live limbs; these trees are more spread out and experience less competition from other trees.  Sycamore trees are taller in the meadow than in the Quarry Bottom; competition is more intense in the meadow where trees coexist with grasses, willows, and other plants.  Some ideas for future studies include spatial analysis of sycamores, measuring water and nutrient availability in the soil, and investigating the history of the quarry and the surrounding areas.