December 2018 – Native Plant of the Month
Written by Guest Contributor: Elenore Goode
Juniper species, Juniperus ashei etc
The many different sturdy and robust trees of the Juniper genus lend a resilient character to the landscapes they inhabit, gifting them with an abundance of berries, protective evergreen cover, and rich organic matter. The presence of this herbivore and drought resistant tree provides an important source of food for many organisms – from birds, mammals, and insects, to the soil microorganisms and plants – that live in symbiotic relationships with the juniper trees through mycchorrizal connections. The stringy bark of mature trees is a staple nesting material used by the endangered Golden-Cheeked Warbler and other birds. Most wildlife consume Juniper in some way, and though it is overall resistant to deer browse, they will eat more and more of it when there is less other food. Goats will readily eat Juniper, and where they are penned with them, they may even kill trees from overbrowse.
Some plants that love to grow in the rich duff made by the fallen needles of Juniperus ashei and the sub/separate species ovata include:
– White Honeysuckle
– Madrone trees
– Texas Persimmons
– Texas Red Oaks
– Yaupon and Possumhaw Hollies
– Cedar Sedge
– Other hardy Salvia species, Pellitory, etc.
To understand the current distribution and overabundance of Juniper trees relative to other species, we look back to the ecological and land use history of the area, and at current land management methods. Junipers in many habitats are frequently the innocent targets of misguided scapegoating campaigns to blame them for the ecological disasters that they are simply cleaning up after.They are the bandages on the open wounds caused from centuries of overgrazing, burning, and denuding hills of all their vegetation.
In Texas, the past few centuries have seen great habitat losses in terms of species diversity and abundance, soil depth, soil moisture and aquifer levels, and various other further compounding interconnected factors that lend to the overall destabilization of habitat regeneration processes in the ecosystem. The loss of other fruiting species of herb, shrub, and tree from a habitat further propels the expansion of the Juniper, since its berries are one of the most available and reliable food sources that provide food for wildlife throughout winter. Subsequently, these animals distribute the berries across the landscape, especially under the live oaks they like to sit in – if you want fewer new Junipers, start by giving wildlife something else to spread!
In the same way that many of our garden weeds are trying to restore minerals and organic matter to the soil and tell us that something is needed there, many of the places where multitudes of Junipers sprout up are simply in need of some kind of vegetative cover and soil organic matter, due to livestock or deer pressure preventing anything else but Juniper from growing. Restoring the abundance and diversity of the thick and diverse vegetation native to Texas will help prevent so many young Juniper seedlings from appearing.
Juniperus species are highly drought-adapted trees that need and use very little water, which is how they are able to survive in such rugged climate conditions. Juniperus ashei is able to grow in poor, dry and alkaline conditions of the Hill Country where few other plants can, and has proven itself as an incredible early-successional species to set ecological and hydrological functioning back into motion where it has been brought to a near halt in the “moonscapes” created by anthropogenic habitat degradation. Forests are rainmakers, holding onto rainfall in their locality through their body mass, so that the water remains available in that area rather than flowing off to sea, and allows the landscape to maintain local/small hydrological cycles and healthy springs through the respiration of plants. The dominant Juniper forests of many brittle and dryland habitats are essential for holding moisture in the local landscape in the form of biomass and soil moisture levels, and if they were to suddenly be removed, remember that what is also being removed from that place are the effects and potential of a large volume of water that is part of the local water cycle; all the water that is contained within the trees, and the soils they make and keep moist with their shade. Another way forests increase soil moisture is by drawing dewdrops out of the air in certain conditions, and they can then fall to the ground.
Juniperus species act as nurse trees across many different habitats by protecting more palatable plants under their branches and creating rich organic matter from poor substrates for other plants to grow in. They are an integral species in ecosystems that have lost their historic plant diversity, and that are still under unnaturally high deer and livestock browsing conditions due to the feed supplementation of these populations beyond what the local carrying capacity of the land can handle.
The abundance of Juniper trees in the degraded hills and rangelands of Texas speaks to its hardiness amidst the severe erosion, deforestation, and overbrowsing/grazing that have eradicated the more palatable vegetation. On steep slopes, Junipers provide essential coverage for the soil, and their dense layers of branches help break the impact of the heavy and intense downpours common in Texas, helping the rain to percolate into the soil instead of washing it off the hill and contributing to flooding. Rather than focus efforts on opening up more of the historically-abundant forest canopy in a state where we can’t stop complaining about the heat, we should remember that the original forests of Texas were rich with understory grasses and shrubs that thrive in dappled and even deep shade. The lack of species richness in many dense, young, re-growth stands of Juniper is due more than anything to the fact that the seed bank for other species has already been lost from the spot in question by previous poor land management. Most Hill Country plants will happily grow in a Juniper-derived soil when re-introduced properly.
The Juniper species across their habitats must be re-envisioned as what they are: truly vital backbones holding the ecological functioning and integrity of their habitat together, and repairing it from centuries of land mismanagement.
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