forestry

Pennsylvania Invasive Plant Information

Penn State Extension has released updated guides to the invasive plants of Pennsylvania — these are excellent free info for landowners struggling with non-native plants taking over their properties.  

A synopsis of the threats posed by these invasive plants, from the Invasive Plant Sheet Series announcement:

The term “invasive” is used to describe a plant which grows rapidly, spreads aggressively, and […] degrade native environments by causing a decline in native plant species diversity. They degrade wildlife habitats for native insects, birds, and other wildlife and threaten rare species. In addition, invasive plants have been shown to inhibit forest regeneration success, and slow or halt natural succession. Once well established, invasive plants require large amounts of time, labor, and money to control or eradicate.

Invasive Plants of Pennsylvania

Japanese Knotweed - Invasive Plant in Pennsylvania - photo by Dave Jackson
Japanese Knotweed - Invasive Plant in Pennsylvania - photo by Dave Jackson

Once Pennsylvania landowners learn how to ID these invasive plants, they can effectively “implement control measures to help prevent further spread and habitat degradation,” hopes David Jackson, Penn State Forest Resources Educator, and co-author on many of the species sheets.

Direct links to the species most problematic in the Cook Forest State Park area are in the bullet list above – or find an links to all the invasive plant species fact sheets via the button above.   

Even MORE information, including the most effective methods of control, are indexed at the Penn State Extension Invasive & Competing Plants page

Acorns: Science & Mysteries

Penn State Forest Stewards series article – written by Jim Finley, Professor Emeritus, Forest Resources Management, Center for Private Forests at Penn State.

Oaks are economically important tree species in Pennsylvania and across the East. Acorns, or mast – a word derived from old English which means “forest food,” are important to wildlife. Oak-borne mast production varies from year to year. Much research has sought to predict masting years, when big acorn crops occur, and shed light on what leads to poor years – or early acorn abscission (detachment) – like you may have seen this season.

Science and Mysteries of Acorns - Pennsylvania Forest Stewards article

Oaks separate into two groups, popularly referred to as red and white, and learning to identify the difference between the two groups is easy.

Red oaks – e.g. Northern red oak, pin oak, scarlet oak, and black oak – have small “bristles” on the lobes and tips of their leaves. White oaks – e.g. white oak and rock, or chestnut, oak – lack these bristles, and have rounded leaf lobes.  (CFC note: the image above is of a white oak.)  There are other differences that are more difficult to recognize, such as acorn structure and wood anatomy.

The Process of Creating an Acorn –
and the Trials of 2020

Both red and white oaks produce female and male flowers on the same tree, unlike ash which has male and female trees. The process of producing an acorn starts late in the growing year when the male flowers form as the tree’s growth slows toward the end of summer. That is the end of the first year (year 1) in the process. Then, in the second year (year 2), as the tree comes out of dormancy, female flowers form in the axil of the leaf stem and the twig and remain dormant. As the spring leaves begin to unfold, the male flowers emerge and are very apparent as rather-long, drooping, greenish-yellow catkins. These appear about two weeks before the much smaller female flowers emerge.

White Oak Acorn Production

For the white oaks, as the male and female flowers emerge in year 2 as described above, pollination and fertilization should happen. The pollen from the male flower, which is wind-disseminated, lands on the style, which is part of the female flower. When this happens, the pollen initiates the development of a pollen tube that transfers male cells into the ovule to complete fertilization and the process of acorn formation should start in earnest. For this to happen, it is ideal to have warm days and cool nights. 

If temperatures are not right, fertilization may fail, and the female flowers will abort, which results in low acorn initiation. Alternatively, if temperatures become too hot or drought conditions occur, white oak acorns may abort, which is likely apparent in mid-June to mid- to late-July; perhaps that is the reason for reported early acorn drop this year. The other big threat to white oak acorns is late spring frosts, which also happened this year, and would again remove the fertilized flowers.

Trees and Dry Conditions

Penn State Forest Stewards series article – written by Allyson Muth, Interim Director, Center for Private Forests at Penn State.

Many areas across the northeastern US are experiencing dry and drought conditions, Pennsylvania included. As of July 28, two-thirds of Pennsylvania was in an abnormally dry to moderate drought condition. Yet, tallied across the state, we are very close to the total predicted rainfall for an average year to date. Depending on where you look in Pennsylvania, the regions are somewhere between 25% below, to as much as 26% above annual precipitation. These numbers don’t sound like they would result in two-thirds of the state be in abnormally dry conditions. So, how does that work?

PAFS article tree health during drought

Climate Change

Climate change models for Pennsylvania have consistently predicted the pattern that we’re seeing this summer. Less frequent, but more intense rainstorms, with extended drought periods occurring between those large rain events. The result is highly variable and uneven conditions across the state. Conversations with landowners in the south central region have shared their recent 4-inch rain storm events and subsequent flooding. In many other Pennsylvania regions, rains came early, and we’ve entered a dry summer period with rather infrequent rain events.

Pennsylvania is known for its waterways – over 86,000 miles of streams, creeks, and rivers. We usually have ample water during the growing season. We rarely have the water conservation requirements that the US West and Midwest implement to conserve water for human consumption. But when it’s this dry, do we need to worry about the trees?

Contributing Factors

Healthy, established trees can normally withstand relatively long periods of drought, so long as there are intervening months or years that are more favorable. However, recently planted trees, or trees with small soil footprints (rootprints?) are more susceptible to decline under these dry conditions. 

Forest Resilience in a Changing Climate

Penn State Forest Stewards series article – written by Jim Finley, Professor Emeritus, Forest Resources Management, Center for Private Forests at Penn State.

So far for most Pennsylvanians, Winter 2020 has been a non-event. Depending on where you live, temperatures are considerably above normal and snowfall below normal. Individual perspectives might lead to interpreting these two statistics as either positive or negative. No snow equals no shoveling. Warm temperatures equal more time outside. Or, no snow equals no sledding or skiing. Warm temperatures equal more ticks.

Thinking more broadly than personal values or needs; Is this winter’s weather a harbinger of a future driven by climate change? If so, how will Pennsylvania’s forests respond?

PA Forest Stewards - Jim Finley on Climate Change 2020

For sure, weather is fickle. Mark Twain purportedly said, “Climate is what we expect, weather is what we get.” It seems something is happening to the climate and, whether you attribute it to human activities or just unexplainable variation, Pennsylvania’s forests are facing challenges.

Forest Resilience in a Changing Climate

Aldo Leopold, a 20th century mid-western conservationist, and author of The Sand County Almanac and many other writings about our relationships to the land and natural systems, was a keen observer of change that others seemed to miss. He wrote, “One of the penalties of an ecological education is that one lives alone in a world of wounds. Much of the damage inflicted on the land is quite invisible to laymen . . . in a community that believes itself well and does not want to be told otherwise.” Simply, he was saying that the more one knows about ecology, the more apparent change is and that many will neither see nor believe that it matters. Many resource professionals as well as laypeople are seeing change in many areas of our environment. As Leopold suggests though, many of these changes and linkages may not be obvious to less than “keen observers.”

Disturbance and change are part of natural systems. Resilience is the ability of a system to recover after disturbance, which determines its ability to persist and function over time. The degree and extent of a disturbance logically affects the capacity of a natural system to recover. For example, in a typical winter, forests often experience damage from wind and ice. Most commonly this is local damage and a few trees experience broken limbs and some trees tip over. The ability of the forest to function across a larger landscape continues unabated – some trees benefit from increased light and growing space from the loss of their neighbors – the forest almost ignores the event.

Service Foresters

PA DCNR service forester program for landowners

DCNR service foresters – at no cost to the landowner – will walk your property, and give sound advice on the following:

  • Woodland review & improvement 
  • Tree planting
  • Control of forest pests & invasives
  • Wildlife – habitat & management
  • Woodland recreation
  • Educational & cost-share programs
  • Forest management 
  • Timber harvest 
  • Riparian & water quality practices 

Under the Cooperative Forest Management Program of the DCNR Bureau of Forestry, a Service Forester will assist you in understanding and planning the care and management of your woodland – a service to help you gain the maximum in benefits and enjoyment from this resource acreage.  While they can’t mark or sell timber, and don’t compete with private consulting foresters, they provide an educated, disinterested opinion and help you progress to the next step of managing your woodlot wisely and sustainably. 

To connect with your county’s service forester, contact: 

Clarion, Jefferson, Armstrong, Butler, Beaver, Lawrence & Mercer counties: 

Clear Creek Forest District 8
158 South Second Avenue
Clarion, PA 16214
(814) 226-1901
fd08@state.pa.us

Forest, Venango, Warren, Erie, & Crawford counties:

Cornplanter Forest District 14
323 North State Street
Warren, PA 16365
(814) 723-0262
fd14@state.pa.us

Some Litter Is Necessary

Penn State Forest Stewards series article – written by Jim Finley, Professor Emeritus, Forest Resources Management, Center for Private Forests at Penn State.

Well once again, Pennsylvania’s forests are a mess – full of litter. Following the annual spectacular display of colors, fallen leaves, twigs, and branches “litter-ly” despoil our forest floors with layers of brown discarded leaves. What a mess!

2019-11 PAFS article Jim Finley on leaf litter

Depending on your awareness of litter’s value and your aesthetic sensibilities it can result in different appreciation levels. If you are a gardener, you would welcome, collect, compost, and hoard tree leaves. If your taste leans toward green grass lawns, you may abhor fallen leaves. Either way, you will likely gather them up; however, there are some who want to leave them in situ and mow them into increasingly smaller pieces to foster quicker decay hoping they will benefit that lawn.

Forests full of fallen leaves are a gift trees give to themselves. No one rakes or mulches them; nonetheless, they do slowly disappear. Estimates are that a mature hardwood forests produce an estimated 2,000 and 3,000 pounds per acre of litter annually. While most of this (about 70%) is leaves, it also contains twigs and branches, which may be partially decomposed prior to falling. It is amazing that through natural decomposition processes, tons of leaves contribute to forest vitality and health in so many ways.

 

Scouting for deer browse

Penn State Forest Stewards series article – written by Dave Jackson, Forest Resources Educator, Penn State Extension and Matt Russell, Associate Professor/Extension Specialist, University of Minnesota

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!

PAFS series - Dave Jackson on Deer Browse

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.

What is Forest Fragmentation & Why is it a Problem?

by Michael Snyder, forester & Commissioner of the Vermont Department of Forests, Parks, and Recreation. 
Generously permitted for re-publication by Northern Woodlands magazine – original article here

forest fragmentation photo by Pok Rie from Pexels

Forest fragmentation is the breaking of large, contiguous, forested areas into smaller pieces of forest; typically these pieces are separated by roads, agriculture, utility corridors, subdivisions, or other human development. It usually occurs incrementally, beginning with cleared patches here and there – think Swiss cheese – within an otherwise unbroken expanse of tree cover.

Over time, those non-forest patches tend to multiply and expand until eventually the forest is reduced to scattered, disconnected forest islands. The surrounding non-forest lands and land uses seriously threaten the health, function, and value of the remaining forest.

Any large-scale canopy disturbance affects a forest, but it is important to distinguish between a forest fragmented by human infrastructure development and a forest of mixed ages and varied canopy closure that results from good forest management. The former is typically much more damaging to forest health and habitat quality, usually with permanent negative effects, whereas the latter may cause only temporary change in the forest.

The effects of fragmentation are well documented in all forested regions of the planet. In general, by reducing forest health and degrading habitat, fragmentation leads to loss of biodiversity, increases in invasive plants, pests, and pathogens, and reduction in water quality. These wide-ranging effects all stem from two basic problems: fragmentation increases isolation between forest communities and it increases so-called edge effects.

When a forest becomes isolated, the movement of plants and animals is inhibited. This restricts breeding and gene flow and results in long-term population decline. Fragmentation is a threat to natural resilience, and connectivity of forest habitats may be a key component of forest adaptation and response to climate change.

Edge effects are even more complicated. They alter growing conditions within the interior of forests through drastic changes in temperature, moisture, light, and wind. Put simply, the environment of the adjacent non-forest land determines the environment of the forest fragment, particularly on its edges. This triggers a cascade of ill effects on the health, growth, and survivability of trees, flowers, ferns, and lichens and an array of secondary effects on the animals that depend on them. Ecologists suggest that true interior forest conditions – you know, where it’s hard to hear cars and lawnmowers and it remains cool, shady, and downright damp even during a three-week drought – only occur at least 200-300 feet inside the non-forest edge.

And so a circular forest island in a sea of non-forest would have to be more than 14 acres in size to include just one acre of such interior forest condition. Put differently, reports indicate that the negative habitat effects of each residential building pocket within a forest radiate outward, affecting up to 30 additional acres with increased disturbance, predation, and competition from edge-dwellers. This may not matter to generalist species like deer, raccoons, and blue jays, which may actually benefit from fragmentation, but it is hell on interior-dependent species like salamanders, goshawks, bats, and flying squirrels. The smaller the remnant the greater the influence of external factors and edge effects. A wise person once likened it to ice cubes: the smaller ones melt faster.

Moreover, as forest fragments become ever smaller, practicing forestry in them becomes operationally impractical, economically nonviable, and culturally unacceptable. In turn, we lose the corresponding and important contributions that forestry makes to our economy and culture. The result is a rapid acceleration of further fragmentation and then permanent loss.

Here is the tricky part: when fragmentation occurs in a heavily forested region like ours, at least in the early going we are still left with a largely pleasant condition. We sense that we still have lots of woods where we can work, hunt, ski, and walk the dogs. And to most of us, this seems good enough, even when the perforations expand and those woods are the scattered remains of a fragmented forest.

But is it enough? At some point when the larger forest is highly fragmented, the size, integrity, and connectivity of those wooded remnants deteriorate beyond recovery and they are no longer adequate for native forest plants and wildlife. After all, when the Swiss cheese has more holes than cheese, the whole sandwich suffers.

aerial forest fragmentation - Tom Fisk on Pexels

Fallen Giants of Cook Forest

Courtesy of Dale Luthringer, Cook Forest State Park Naturalist: 

It is with great regret that I inform you that both the Longfellow Pine & the Seneca Pine succumbed to a microburst on 4 May 2018.

A fast moving microburst came through the area early Friday evening with winds reported near 70 mph.  Firsthand accounts state the duration of severe heavy wind in the park was likely a mere 5 minutes.  I was in Erie at the time [and] spoke to a park patron on the trails on Monday, who was from Toronto where his high rise work building experienced winds in the 120km/hr range resulting in several windows being blown out.

Many tall pines are down, and to conduct a complete assessment will take time, but a preliminary brief cruise of trails in the heart of the Cathedral note mostly all recently felled trees suffered trunk failures, with most trunk failures being at the 40-60 ft height range.  There are still two tall upper 160 ft class pines standing near where the Longfellow was that I haven’t measured in close to 10 years.  Maybe one of them might make 170.  The Burl King (~11 x ~160), located a stone’s throw NW of the Longfellow appears to have come down in either one of last year’s May 2017 microburst events.

The Cornstalk Pine (~14 x ~135) adjacent to the Seneca Pine is still standing, but appears to have lost some of its crown.  I’m hoping the Cook Pine (~12 x ~165) is still standing.

So as it stands, the current tallest pine in Cook Forest and PA is one between the Seneca & Mohawk Trail last measured at 9.6 x 170.5 several years ago.  The current statistics I have for the PA state champ would have to reside at Heart’s Content, ANF, with the Heart’s Content Pine, last measured at 12.9ft CBH x 160.5ft high.  I will be measuring the Heart’s Content Pine in a couple weeks due to programming being held their soon.  It’ll take me some time to see the Cook Pine to check on its current status.

We are looking at getting cross sections for both the Longfellow and Seneca Pine.  The Longfellow’s cross section will have to be taken at over 60ft up from its base, but the Seneca’s should prove more fruitful with a cross section that should come from the 20-25ft height range.

At their greatest dimensions, the best I’ve been able to do for both trees were:

  • Longfellow Pine = 11.2ft CBH x 184.7ft high (previous tallest tree known north of the Great Smoky Mountains
  • Seneca Pine = 12.6ft CBH x 174.1ft high (previous Pennsylvania State Champ)

Both the Longfellow and Seneca have been in decline for years.  The Longfellow was still putting on height, but close to 20% of its bark circumference had rotted near the base.  The Seneca Pine was in much worse shape, with thinning crown and near 50% of its bark circumference rotted near the base.  

Even in death these massive trees tell a story and serve a purpose.  Still, it is sad to see these monarchs pass into the next stage of the forest cycle.  Nothing or no one lives forever.  Something we all need to be reminded of from time to time.

The mantel for tallest tree in the Northeast now passes to Cook Forest’s sister, the Mohawk Trail State Forest [in NW Massachusetts].