story to find out more.
Charlie Feldhake uses a hemispheric lens to photograph the tree canopy from the
forest floor. The images help determine how much sunlight can reach
silvopasture plants. Click the images for more information about
Shade Trees Can Protect Forage Plants
By Don Comis
August 11, 2005
Giving forage plants, as well as animals, some shade from trees could
be profitable for farmers, especially those farming marginal lands.
Belesky and animal scientist
Neel of the Agricultural Research
Service (ARS) are in their fourth year of raising lambs on oak and conifer
silvopastures, combinations of forages and trees growing together on the same
land. Belesky heads the team of scientists at the ARS
Farming Systems Research Center in Beaver, W.Va.
The scientists have found that some plants do better under moderate
shade than in traditional open pastures. For example, Neel found that
moderately shaded forage has more protein than forages on open pasture during
the heat of July and August.
Silvopastures also seem to buffer drought and other seasonal extremes.
Feldhake found that this buffering includes helping forage plants warm up about
two weeks earlier than usual in the spring and to stay warm enough in late fall
to hold off the hard frost for about two weeks. These effects are greatest
This means silvopastures could provide another four weeks of forage
growth and grazing time. The extra warmth in cool seasons comes from thermal
radiation trapped and returned by the tree canopy.
The silvopastures are designed carefully, from the size of the trees
to the amount and quality of sunlight allowed to reach the forest floor. The
sites have instruments to monitor light, soil temperature, wind speed,
precipitation and soil moisture.
The amount of light-buffering from tree shade has to be just
right--not too much or too little. Researchers in other regions have found that
tall fescue and orchardgrass grown in moderate shade yield better than those
grown in heavy shade. Neel has found that pasture plants do best in up to 25
percent tree shade in the frequently cloudy Appalachian Region.
about the research in the August 2005 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.