We are back in a shady hammock, this time its an Oak Hammock. There is a large Southern Live Oak a little ways off the trail with smaller ones around. You can estimate the age of this tree by measuring the circumference (in inches), computing the diameter and multiplying by a growth factor specific to the tree species. In the case of the live oak the growth factor can be quite variable so a reasonable age estimate is determined by using 4 as the growth factor. Using this formula, this large oak has survived drought and deluge and poor soild for about 100 years.
Some plants are adapted to mooch off oaks and other plants. Notice the lighter green leaves and spines on the shrub right in the middle of the oaks. This is a Hog Plum (Ximenia americana) and once you identify its light green leaves you can see that it is a substantial shrub that has had to grow long branches to reach the sun. The Hog Plum is a root parasite. Its roots reach out through the soil to find the roots of an oak. When it finds the oak roots, its grows projections, called haustoria, that pierce the root and tap into the sugars that the oak makes for itself.
The Hog Plum produces white fuzzy flowers that form a yellow fruit that is important food for wildlife. Every part of this tree contains cyanide compounds and oils that have been used for medicinal purposes, food, and for tanning leather. So even though it is a moocher, maybe it is giving back a little too.
A few steps further to the right you will notice a Laurel Oak (Quercus laurifolia). This species looks similar to the Southern Live Oaks but the trunk and branches tend to grow more vertically. One of the characteristics used to identify species of live oaks is the hairs on the underside of the leaf. The Southern Live Oak has a dense cover of matted hairs that can be seen under magnification. The Laurel Oak has no hairs or just a few placed in the crook where veins meet as seen in the picture. I saw this referred to as "armpit hair".
