Posts Tagged: Bill Tietje
Californians love their oak trees. During vineyard development, Central Coast grape growers often feel compelled to leave an old iconic oak standing, even if it ends up right in the middle of their vineyard. While driving through the Central Coast, it's not unusual to see the pattern of vineyard rows broken by a majestic oak tree. Aside from their beauty, what are some of the ecosystem services that these majestic trees provide?
To understand the potential value of remnant oak trees for insectivorous bats, the researchers placed microphones to detect bat calls within 14 Central Coast vineyards. The recordings revealed 11 species of insectivorous bats foraged within the vineyards and bat foraging activity was 1.5 times greater at the trees compared to open, tree-less areas within the vineyard. And the bigger the tree, the bigger the number of bats it attracted.
“The study results suggest that the large oak tree in my vineyard not only increases the beauty and biodiversity of the agricultural landscape, but also attracts insect-eating bats that can provide natural pest control—a win-win,” said grape grower Jerry Reaugh, who cooperated with the researchers.
Tietje hopes that the free insect-reduction services provided by bats will increase grape growers' incentive to manage and maintain the trees, and even to plant new oak trees in suitable areas around their vineyard, in mutual benefit to both agriculture and biodiversity.
“In addition to their value for insectivorous bats, remnant trees maintain bird and insect diversity by providing food, habitat, cover and stepping stones that facilitate the movement of wildlife within agricultural landscapes,” said Tietje.
This study comes at a time when declining blue oak and valley oak populations are of great concern.
“We hope the study will increase awareness of these beautiful and beneficial trees and make the case for conservation and restoration,” Tietje said. “Preserving and enhancing biodiversity in the midst of climate change is key to ensuring resilience in our landscapes and communities.”
The beauty of rolling hills studded with majestic oaks, other trees and shrubbery isn't the only reason to regenerate vegetation. The trees and shrubs create a much more hospitable habitat for a wide assortment of wildlife. Oak woodland vegetation also protects the quality of California water. The majority of the state’s water flows through oak woodlands in streams and rivers that support fisheries, farms and cities. Plants and trees anchor the soil, preventing erosion and stream sedimentation.
One of the difficulties ranchers face in regenerating trees is supplying water for seedling establishment. Ranches often stretch for thousands of acres. Hauling water to remote sites or installing irrigation can be prohibitively expensive.
Third-generation San Miguel rancher George Work heard about a new tree establishment invention from Holland – a Groasis Waterboxx. Over the years, Work has collaborated with UC Cooperative Extension on oak planting projects and consulted with UCCE experts about squirrel diseases, ranch animal vaccinations and pasture management. He turned to UCCE natural resources advisor Royce Larsen for his thoughts on the Waterboxx.
“Because of Royce here, our Cooperative Extension agent, he provided a little added incentive when I wanted to try this thing,” Work said. “Royce said, ‘I’ll help you.’ Well, that was enough to get the job done.”
Work, Larsen and UC Cooperative Extension natural resources specialist Bill Tietje installed 10 Waterboxxes, which cost about $30 each, in a remote area of the 12,000-acre Work Ranch in southern Monterey County. Other plant regeneration methods – including traditional drip irrigation and tree teepees – were also installed for comparison.
The Waterboxx is a round plastic hat box-shaped reservoir that fits around the seedling trunk. When the seedling is planted, the reservoir is filled with about four gallons of water. A rope on the bottom continuously wicks moisture to the plant roots.
The box is covered with an inward-slanting corrugated top that cools during the night and channels condensed dew and fog into the reservoir, keeping it full of water. The Waterboxx provides a protective barrier around the trunk and shades and cools the soil beneath. At the Work Ranch, the plants are also enclosed in bale-wire fence to keep out wildlife poking around for water or hungry for tender green growth.
“The trees are doing surprisingly well," Larsen said. "In just three months, the seedlings have grown more than two feet."
Larsen said he will continue monitoring the project to see if the self-watering system can establish trees. If successful, UC scientists may study the Waterboxx more thoroughly in a replicated research design in Monterey County, San Luis Obispo County and other parts of the state.
See the components of a Waterboxx in the video clip below.
“The public doesn’t always realize what ranchers are doing and how that benefits everyone,” said Bill Tietje, UC Cooperative Extension natural resources specialist based in San Luis Obispo County. “No one really thinks about it, until it’s gone.”
Many rangeland benefits can be grouped as “ecosystem services.” According to scientists:
- Rangeland plays a role in the state’s water cycling. Eighty percent of California water flows through rangeland.
- The diversity of plants and animals is greater on grazed, managed grassland than on unmanaged grassland.
- Wild raptors overwinter on grasslands managed for beef cattle.
- Half the habitat for the tiger salamander is grazed stockponds, created by ranchers to provide water for their cattle. The stockpond’s edge of clipped grass and the absence of crowding shrubbery mimic the rare species’ natural habitat – vernal pools.
- Rangeland provides habitat for insects that are valuable for pollination.
- Cattle reduce the dry grass that could fuel wildfire.
- Grazing improves the habitat for the Bay checkerspot butterfly, a threatened California insect.
- Rangeland sequesters carbon in the soil.
There are threats to the long term viability of cattle ranches in California that put all these benefits at risk:
The sale of the ranch for development is very attractive for a rancher who isn’t making a sufficient profit on the land. Also, the division of a ranch for inheritance purposes can make it difficult to keep a ranch intact and in the business of raising cattle.
UC Berkeley professor of rangeland management and ecology Lynn Huntsinger said public misunderstanding of and a lack of appreciation for ranching is another way the system is threatened.
“Imposing regulations that aren’t needed and not valuing ranchers as stewards can have a demoralizing effect,” Huntsinger said.
Much of the land grazed by ranchers is public and grazing is supported by public and environmental agencies - the U.S. Forest Service, Bureau of Land Management, parks and preserves - because of the many benefits it provides.