Forage Yield and Quality Under Oak Crop Tree Management Mike Demchik University of Wisconsin Stevens Point.

Forage Yield and Quality Under Oak Crop Tree Management

Mike Demchik

University of Wisconsin Stevens Point

The Issue

• 800,000+ acres of woods are grazed in MN• Foresters ignored the potential for wood

from grazed woods• Forage from woods is often low quality and

low yield (200 lbs per acre or less)• Most woodlots are overstocked with trees

and cattle (too many trees or cattle)• Cattle can damage trees

Photo by Randy Cyr

Not always, however

Photo by Thomas Croker

Photo by David Moorehead

Cows in an autumn landscape.Viktor Westerholm (1885) Finland

The Question

Can management of the woodland benefit the forage yield and quality?

The Effect of Canopy Shading

• Cool season and low nutrient plants dominate

• Cool season grasses need and can use less light than warm season grasses

• Warm season grasses grow MUCH faster than cool season grasses- higher yields

• Full canopy can mean less than 100 lbs/acre forage

Side one: How to Improve Forage Growth

• Open up the canopy– More light equals more warm season grasses– More light results in more and better forage

• Seeding- at low yields may not be economically feasible and what do you plant??

Side two: How to Improve Tree Growth and Value

• Open up the canopy

• Select your best trees

• Remove most of the rest

• Use short duration, high intensity rotation during spring or fall (low bugs too)

• Avoiding wet soil (swamps) reduces the amount of soil damage

The Idea

• Crop tree management is the best solution

• Crop tree involves concentrating most of the growth in the stand on the best trees

• The inefficiency of crop tree management is that a lot of light makes it to the forest floor

• This is where you are growing your forage

The Site

• Cass Co., MN, USA• Glossaquic Eutroboralfs soil

– Perched water table Oct-June (1 meter of surface), high levels of soil bases, northern mixed sandy-loam Alfisol

• Natural forest vegetation (25 m2/ha)• Quercus macrocarpa, Pinus resinosa, Betula

papyrifera • Grazed for more than 30 years (possibly 100)

The Project

• Three sites marked for crop tree management • Three sites as controls• Cutting done in winter of 2002-2003• Three fenced sub-plots in each plot (total of

18)• Forage samples taken in early summer and late

fall 2003

The Crop Tree System

• Release the crown on three or four sides

• Target basal area 18.5 m2/ha

• Selecting 50-70 trees/ha as crop trees

• Leave about 15 feet between crowns of crop trees

Before Crop Tree

After Crop Tree

Results (2003)

Crop Tree

kg/ha

Control

kg/ha

Early Season 520 144

Late Season 288 45

Total 809 189

Results (2004)

Crop Tree

kg/ha

Control

kg/ha

Early Season 821 109

Mid Season 512 86

Late Season 84 12

Total 1418 207

Relative Feed Value

• In general, early season feed values and protein were similar and good (suitable for dairy animals)

• Later season values are poorer overall and worse in the unmanaged stands

Conclusions

• Crop tree management has been shown in other studies to be a good method for increasing sawlog value in a relatively short time (10-20 years)

• It appears that this method also increases forage production

Will this Work for Farmers?

• YES! Minnesota has a very long, cold winter• Farmers often burn wood to heat (up to 10

cords/year of mixed hardwood)• Thinnings from 1-3 acres of crop tree can supply a

winter’s firewood• Most farmers are used to “weeding” a garden and

“weeding” their woods appeals to them

Half of my fuelwood for one winter…

Past Extension Efforts

• Forest management for Cow-Calf operators

• Growler series (three sessions included this topic)

• A technical publication

Integrating farming and forestry can be ecologically and economically rewarding as well as result in a beautiful landscape.