Probably most people travelling from the Gulf Coast of Texas to the Hill Country and beyond notice all the Live Oaks but they probably don't know that the Live Oaks in the Hill Country are not the same as those along the Gulf Coast, and for that matter all the way from the Texas Gulf Coast to the Atlantic states up to Virginia. Digging even deeper into the variations of the Live Oaks, the classical live oak of the Gulf Coast that thrives in the heavy soils all the way to Virginia only exists in the eastern part of the Texas Gulf Coast. Texas has five forms of the Live Oak, one of which is the Quercus Virginiana, and the other are modifications, if you will, of the Q.Virginiana and they are all Quercus Fusiformis. The Latin name of the four variations comes from the observation that a distinguishing factor between the Q. Virginiana and the other four Q. Fusiformis is the long, slender acorn of the Fusiformis
In summary these five are in the Live Oak Complex
- Live Oak (Q. Virginiana)
- Escarpment Live Oak (Q. Fusiformis)
- Q. Virginiana x Q. Fusiformis
- Q. Minima x Q. Fusiformis (small zone of growth along the sandy coast of Texas)
- Q. Oleoides x Q. Fusiformis ( small area of growth along the lower sandy coast of Texas)
From this list, the classic live oak is Quercus Virginiana with its range from just west of Galveston Bay in the coastat counties, all the way to the Carolinas. The Live Oaks of our immediate area run from the Balcones fault line northwestward for about a hundred miles. This is the Quercus Fusiformis. Then to make things even more complex, there is a hybrid that grows in the area between the Fault Line and the range of the Live Oak of the coastal area. So, if driving from the Houston area to the hill country, you would pass through the territory of the Q. Virginiana x Fusiformis. The fact that the Balcones fault line separates the Fusiformis from the Virginiana x Fusiformis would suggest that the abrupt change in soil is the dominant determining factor. Temperature and rainfall may also be a factor as well.
Which brings us to the dilemma of the St. Valentines Day polar blast and the very slow recovery of the Live Oaks in our area. Our observations indicate that some of the oaks are having more trouble leafing out than others. It just so happens that the boundary between the Q. Virginiana and the Q. Fusiformis runs right along the Balcones escarpment, with the Virginiana x Fusiformis being happy and contented with conditions south of us and the Q. Fusiforma content with the conditions north of this line.
But the line between the two variations can move with time and temperature. Of course the line of tolerance on temperature is fuzzy and it depends on the amount of time that the tree experiences at low temperatures. For example, in the Dallas area, where the Live Oak had been planted extensively, it was nearly completely obliterated in the freeze of 1983 when the temperature was below freezing for 12 consecutive days.
Knowing that there is variation in everything in nature, the speedy recovery of some of our Live Oaks compared to that of others right next to them would suggest that at this boundary line between Live Oak varieties is vague and we may have two kinds of Live Oaks in our local forest. If we see some of our Live Oaks die, it may simply be that they were q. Virginiana x Q Fusiformis. Time will tell, but so far, we have spotted only two trees that look in really bad shape.
Another factor causing the decidedly slow leafing out of our live oaks may be caused by abnormal sap withdrawal to the root system from this very cold February and cold spring to boot. We all know that deciduous trees only leaf out when the sap flows up from the roots and that timing is related to moisture and temperature. Who knows, the Live Oak may be right on the edge of being a deciduous tree. But then we wouldn't want to call it a live oak.
As to the pesky but very attractive Huisache, it appears that the few that we had are dead from the freeze. Note all the dead Huisache along the roadside of Old RR12 just after leaving Wonder World Drive at the LaCima entrance. A warming trend brought them up this far from the southern part of Texas and a cooling trend sends them back home.
The same goes for the Palo Verde mentioned in the previous month blog post. It now appears that all the Palo Verdes trunk and limb structurer is dead but the plant is coming back from the roots.
We haven't searched out the fate of the Olive orchards, but it is likely that these trees are gone.
