Scouting for deer this fall? Scout for deer browse, too.

Severely browsed beech seedling

Many woodland owners take to their woods in October to begin scouting for deer season. A good way to learn more about where white-tailed deer might be found is by understanding what they’re eating. A deer’s diet consists of a variety of crops, herbaceous and woody vegetation, fruits, and nuts. A healthy diet will consist of a variety of different foods. A deer requires an estimated 6 to 8 percent of their body weight daily in forage to stay healthy. For a 150-pound deer, that’s up to 12 pounds of food every day!

Too much browsing pressure, eating twigs and young shoots, from deer can kill or limit the growth of tree seedlings, a fact that foresters and woodland owners know very well. Over decades, deer populations can greatly impact the look of woodlands. Knowing which tree seedlings are growing in your woods and which ones are browsed can give you more details on a deer’s diet.

In Pennsylvania, tree species that rank high on a deer’s list include a number of hardwood trees. Red and white oaks are two of the primary hardwood species that deer prefer to browse, while blackgum, hickory, and yellow poplar are also very high on the preference list. As you move north, species like maple (red and sugar), white ash, and basswood become more preferred species where they are more abundant.

While deer prefer these tree species they also avoid certain plants. Deer will start by browsing the most preferred or palatable trees first. If there are high populations of deer in an area, preferred plants will see more browsing which can lead to other plants, that deer don’t prefer, taking over.

So what does it mean if deer are browsing beech seedlings/sprouts? Likely that deer are getting desperate and other food sources are limited. Evidence of high deer populations can be seen in a woodland that is dominated by beech brush, striped maple, black birch, black cherry, mountain laurel, ferns (primarily hayscented and New York) and invasive exotic plants. Deer avoid browsing these plants because they are not as digestible compared to other vegetation.

More evidence of deer browse impacts is the presence of a browse line on all understory trees, where there are no green branches until about five or six feet up. Another sign may include the presence of seedlings that are severely hedged and not able to grow above 1-foot in height. As well as understories dominated by species that deer avoid. Deer do not readily eat species like ferns, striped maple, beech, ironwood, mountain laurel, blueberry, and spicebush.  As a result, we see these species dominating the forest understory in many areas.

To have a healthy woodland, tree seedlings need to develop into healthy, mature trees. As an example, consider a browse-sensitive species like oak. First, it can take over thirty years for an oak tree to produce acorns. Second, acorn crops only occur every two to five years and truly “bumper” crops much less often. In these good crop years, acorns can make up the majority of a deer’s diet in the late fall. If oaks can never make it from acorn, to seedling, to sapling, to healthy mature tree, the habitat quality for deer can suffer in the long term as oaks are replaced by other, potentially less desirable, species.

Knowing which species are being browsed can also give you insight into which methods can be used to protect seedlings. Although costly, fencing can be constructed around individual trees or larger areas several acres in size. Protecting tree seedlings ensures that you have healthy trees for the future while steering deer towards other food sources.

You may also consider harvesting additional antlerless deer. The Pennsylvania Game Commission’s Deer Management Assistance Program (DMAP) helps landowners meet their forest management goals by allowing hunters to harvest additional antlerless deer from a property during the regular hunting seasons.

Areas with low deer browsing pressure provide diverse wildlife habitats. They support healthy understories, preparing the forest for future replacement following natural tree mortality or planned timber harvests. Habitat repeatedly damaged by over-browsing continues to decline, losing its ability to support additional deer and other wildlife. It is important to reach a proper balance between desired habitat conditions and deer populations.

By Dave Jackson, Forest Resources Educator, Penn State Extension

and

Matt Russell, Associate Professor/Extension Specialist, University of Minnesota

Carbon Capture Forests vs. Fields

Ever wonder what the relative capture of CO2 is from an acre of mature forest vs regrowth vs an acre of pasture or corn? For forests it goes like this: 

After harvest, for a few decades, forests are net sources of Carbon (C) to the atmosphere.  That is because the C capture from the atmosphere is low (no trees, low net primary productivity, NPP) and the C loss from the ecosystem to the atmosphere stays the same or increases after harvest because soil microorganisms keep eating soil organic matter and respiring it as CO2.

Then, at some point a few decades after harvest, things switch because tree C capture from the atmosphere increases to the point where NPP is greater than C losses from soil microbial decomposition.  After this switch, for hundreds of years, forests can be net sinks for atmospheric C.

In theory, at some point, an old growth forest should have net C capture of zero as inputs from NPP balance outputs from microbial respiration. In reality, there haven’t been many observations of this theoretical steady state – most forests have net C capture for centuries, but it becomes low in the oldest forests.

Rain fed agriculture, row crop or pasture, almost always has lower annual NPP than the adjacent mature forest vegetation.  However, whether an agricultural system has negative or positive net atmospheric C capture (the balance of NPP inputs and microbial respiration losses) depends a lot on how management practices have changed soil practices recently. 

Under some circumstances, reducing tillage can briefly turn ag systems into a C sink that accrues atmospheric C for a decade or so.  Conversion from annual to perennial vegetation, row crops to pasture, is even better – creating a large sink for atmospheric C for several decades by increasing storage of soil C. 

Like forests, row crops and pastures that have been under the same management regime for long times capture zero atmospheric C because NPP inputs to soil are balanced by microbial outputs. (This assumes all of the harvested product returns to the atmosphere as CO2 quickly when humans eat them or burn them for fuel). The time scales are shorter for these ag systems.  While forests might take centuries to reach this steady state, ag systems might take less than a century. (Jason Kaye, Professor of Soil Biogeochemistry, Penn State University)

For a comparison of carbon storage and accumulation in US Forests based on region and forest type check out the following paper by the US Forest Service: CarbonStorage and Accumulation in United States Forest Ecosystems

Fun Facts:

A 40 acre woodlot of relatively mature (50-year old) deciduous trees absorbs, or sequesters, approximately 30,000 pounds of carbon dioxide per acre in a typical year. And would be emitting about 22,000 pounds of oxygen per acre. The contribution varies with the age of the forest and species involved. (Timothy J. Fahey, Ecology Professor, Department of Natural Resources, Cornell University)

The EPA has calculated the amount of carbon dioxide emitted by the average car at about five metric tons, more than 11,000 pounds, so a single acre of woods would be countering the emissions of about 2.7 cars. For 40 acres, that would be about 109 cars.

Clemson Forestry Professor Writes Op-Ed on Threat of Forest Parcelization

I came across this piece in the Southern Regional Extension Forestry News. Great article highlighting the problems associated with parcelization which I highlighted in my previous post on urban sprawl on farmland. This post points out the same problems are occurring on forestland. 

Clemson University Forestry Professor, Dr. Thomas Straka, wrote an opinion article published by The Hill. Straka argues that wildfires and public lands aren’t America’s only forestry problem. Rather, the rapid parcelization that is occurring across the nation is a threat to family forests. Parcelization results from forest holdings being broken down into smaller parcels. Ultimately, smaller land holdings and more landowners will result in contradictory management goals/styles. Straka contends that these management problems will negatively affect the nation’s timber supply and provides recommendations on how to reduce parcelization impacts. I provided the article below.

Wildfires and public lands aren't America's only forestry problem

By Thomas J. Straka, opinion contributor — 07/22/19

Wildfires and contentious public land policy in the American West, sparking debate about climate change and forest management practices on public timberlands, seem to be the only forestry issues in the news. This suggests that problems with America’s forests are centered on federal land ownerships. Actually, forests owned by average folks are more likely to be a future problem. Lots of regular people own forests. These are called family forests and their future is important for the clean water, wildlife habitat, recreational opportunities and timber they produce.                   

The majority of the nation’s forests (443 million of 766 million acres) are in private ownership. Nearly two-thirds of that private forest is owned by families and individuals, mostly in small holdings. These became the family forests and the nation’s largest forest ownership group (owning 38 percent of forest, while the feds own only 31 percent).

Over the last 20 years, the number of family forest owners increased by over 1 million (to nearly 11 million). Considering just owners with more than 10 acres (eliminating the large backyards), average tract size of a family forest is 66 acres. That’s small by forestry standards.

At the time of the nation’s settlement, just over 1 billion acres was forested; today it is about three-quarters of that. This forest area has remained relatively stable over the past century.  Shifts in land use have helped maintain that stability; population growth and urban development ensure that won’t continue indefinitely.

To read the rest of the article click here.