Let’s go to see Florida upland hardwood trees at a hummock in the CREW. The second part of this blog will focus on the herbaceous plants of the area.
The cover image shows the landscape at the northern end of trail. It is a live oak hammock.
The word hummock is sometimes written as hammock. There is some controversy regarding the origin of the word and the use of the word in context helps to facilitate understanding. In Florida it describes a fertile area that is easily distinguishable from the surrounding Pine Flatwoods and is characterized by broadleaved trees (here, primarily Laurel and Live Oaks) and often cabbage palms and vines. Another term used is ”upland” which may be only a few inches above the flat plane scrubland. In this observed instance the upland may be 5 to 10 inches above the nearby plane.
The C.R.E.W. is an eponym for the Corkscrew Reserve Ecosystem Watershed. It includes more than 60,000 acres and is the largest watershed in Southwest Florida. The plants in this watershed filter, trap and metabolize compounds in the water that may be toxic in downstream waterways, resevoirs and aquifers. The watershed also provides habitat for wildlife and recreation for guests.
This exploration of the Oak-Palm Hammock in the Cypress Dome Hiking Trail of the CREW Land and Water Trust was done on February 1, 2023.
The walk-about:
I walked northward along the green and yellow path. The general terrain varied from wetlands through mesic to xeric elevated land and extensively through the grass and brush undergrowth. I did see a black bear and continued to keep warily looking for him as we both moved northward. There were no bear citing photo opportunities, however, there were other signs of his behavior.
The trail is part of a diverse woodland ecosystem alongside a broad marsh area. It begins with an open grassy area and gradually parses into pine and palm flatwoods. This area shows signs of extensive fire damage with considerable succession regrowth. There were signs of fire that may have been not a prescribed burn. Extensive scorching up the trees including the tree crowns at least 30 feet above the floor were evident. Many of the trees including the slash pines were burned completely to ground level leaving only stumps. There were, however, numerous scorched trees and palms which survived.
Throughout this morning and mid-day walk with numerous stops the area was remarkably silent. There were no birds, very few insects, and the only mammal was the distant black bear. The air was also very still with a temperature of 58 to 65 degrees F. There was a very gradual rise in ground elevation. This was hardly perceptible except for the reduction in moisture of the ground and the gradual change in the flora. Here was an increased density of slash pines and mixed sabal palms. The understory was shorter than the mesic areas near the pond. These uplands may be as little as 10 inches higher than the flats.
Discussion:
The understory of this live oak hammock shows no scorched or burned trees. Yet, there is very little undergrowth even in the areas of bright sunshine. Without testing I suspect that this is the result of chemistry. The trees may release biochemicals that influence the germination, growth, survival, and reproduction of other plants. These allelochemicals may have beneficial or detrimental effects on the organisms and more widely the ecosystem. These trees may release phenolic compounds with which I have had experience. They may be like the black walnut trees on the family farm in Michigan. I suspect also that the generous load of fallen leaves and fruit of these trees will also acidify the soil upon their decomposition.* Along with a less mesic soil, this allelofication and acidification of the understory may significantly alter the growth of herbaceous plants and grasses. This provides less fuel for fire. The growth and reproduction of these trees does not depend upon fire. They have their own survival advantages.
The concept of allelopathic competition between and among plants suggests that grasses might also reduce the growth of small oaks similar but opposite to the effect seen when the oaks are mature. I could not find published reports of this potential phenomenon.
This map represents my view of the area in the reserve that I walked. It is a landscape map of terrain that represents the change in vegetation. The red line is the marked trail of the combined green and yellow trails in the visitor map. The areas marked with colored crosshatching are approximations of growth areas.
What’s next?
Future visits to this area could be in the months of April and May and at an earlier start time when the plants may be in bloom and when the animals will be more active. Additional equipment should include a small shovel for examination of the soil and more specimen collection should be done for chemical analysis and microscopic examination. More time could be spent if there were less construction traffic. The eastward section of this reserve area was not explored at this time. It may have another diverse plant library including the cypress dome. With permission, the adjacent private property north of the fence line could also be explored.
Thank you for your interest in this blog. Please continue to part two of this series of observations of Florida Hardwood Hammocks. Its focuses on the scrub and understory.
References:
*Determination of Allelochemicals in the Environment surrounding ceratiola Ericides
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#hummock #succession #mutation #climax species #herbaceous understory #CREW