Let’s get a few myths out of the way first. To begin with, cedar is not really a cedar, but a juniper. The one that grows around here is Ashe juniper (Juniperus ashei), or blueberry juniper. Growing primarily north and west of us is Redberry juniper (Juniperus pinchotii). Like all junipers, they belong to the Cypress Family of Gymnosperms (meaning “naked seed”), which brings us to the second myth.
The blue berries we see on the female trees are not really berries, although everyone refers to them as juniper berries, but they are actually classified as “fleshy cones.” I have read the definitions of berries and cones and examined our junipers, and for the life of me I can’t see why they are not berries, but all the experts say they are cones.
Another myth is that cedar is not native. But here we have hundreds of references in the writings of early explorers and settlers describing cedar and junipers in great detail. And there is fossil evidence of pollen being here since the Pleistocene Epoch (more than 12,000 years ago).
So, cedar is native, natural, xeric, and evergreen, it has very few diseases or pests, and grows in most all habitats in the Hill Country, except for permanently wet areas. All desirable traits for a tree or shrub. So what is the problem?
The problem is not with any individual cedar tree, but with the prolific way it reproduces and forms new trees and thus becomes too numerous for a healthy habitat and crowds out other native grasses, forbs and woody plants.
In the old days, before European settlers arrived in the Hill Country, periodic grass fires and wildfires killed small cedar bushes and thus kept its numbers in check. After Europeans drove off the Native Americans and grazed the grass short, fewer fires meant more cedar. Then after barbed wire was invented in the 1880s, there was a huge demand for fence posts and a lot of the cedar was cut. But beginning in the mid-1900s, the demand for cedar posts declined and T-posts became available. Since neither deer nor anything else likes to eat cedar, and we have many fewer fires, there is no natural control on the spread of cedar in the Hill Country.
There is also the issue of rainwater interception. When it rains, the raindrops first fall on the vegetation, which will keep the drops from hitting the ground. But once the vegetation is as wet as it can get, all subsequent raindrops will strike wet leaves knocking off another drop of water so that the water begins to reach the ground. This is true of all vegetation, with larger plants (trees) intercepting more rainfall than grass or wildflowers. Once the rain is over, the water on the leaves evaporates back into the atmosphere.
It is best not to think in terms of the percentage of rainfall that is intercepted by a particular plant, but to think of the amount of rainfall (in inches) it takes to soak the leaves. Probably, the average cedar bush intercepts the first ¼ to ½ inch of rainfall, after which the rest of the rain hits the ground, which is where we want it. Whether or not a given cedar bush intercepts more rainfall than a given oak tree depends a lot on the relative sizes and density of the leaves. But when cedar becomes so invasive as to form dense cedar thickets (cedar brakes) the rainfall reaching the ground under these thickets is very much less than the amount that fell from the sky.
The bad news is that if landowners do not manage the cedar on their place, it will continue to increase in size and numbers and the rainfall reaching the ground will continue to be reduced. The good news is that of all the brush species one usually thinks about controlling in the Hill Country, Ashe juniper is the easiest to control, because once cut below the lowest green leaf, it will not resprout from the roots, as most all other species will.
Managing cedar doesn’t necessarily require removing all cedar, but controlling its spread and increase. Replacing cedar with native grasses will absorb more rainfall and make for a more productive range and a healthier habitat, but some amount of cedar adds to the diversity of the habitat.
Until next time… Jim Stanley is a Texas Master Naturalist and the author of the book “Hill Country Landowner’s Guide.” He can be reached at jstmn@ .