Pawpaw, Asimina triloba, is a small understory tree very common in Appalachian forests. The fruit, prized by people and possums alike, has a custardy texture and flavor. The fruit, as well as the tree, is called Hoosier banana, at least in Indiana. Pawpaw is a member of the family Annonaceae, an important family of mainly tropical trees and shrubs. Pawpaw has many tropical characters, from its strange purple flowers to its broad, undissected leaves.

Here are some photos of the amazing flowers and young fruit of pawpaw. Click the pictures for really big images. The purple flower is especially glorious at full screen.

Have you every looked closely at tree leaves in spring?  Our eyes are drawn to showy flowers and flitting birds, but a close look at emerging leaves shows some astonishing beauty. The most interesting thing about spring leaves is the intricate folding.  Leaves are often folded in half (as in redbud and hickory) or have complicated, compact folding schemes (as in oak and ash). Watching leaves emerge from their tight folding in buds to become full-grown leaves is fascinating.

Next time you are outside, have a look at some growing leaves. Visit the same plants over a few days and you will be amazed at the rapid changes you see.

Here are a few pictures of spring leaves in development (I will add more later).  Click on the pictures to see a high-resolution version.

bitternut hickory, Carya cordiformis. Leaflets are folded in half as the rachis (leaf stem) grows.

Yellow buckeye, Aesculus flava. Leaves emerge with the flowers. Leaflets are tightly rolled.

Eastern redbud, Cercis canadensis. Leaves are folded in half as they emerge, quickly unfolding.

northern red oak, Quercus rubra. Bright red leaves are compactly folded along sinuses. The leaves transition from red to green as they unfold.

Two pictures of green ash, Fraxinus pennsylvanica.  Leaflets are folded in half and folded against the rachis, spreading and unfolding as they develop.

My article on trees, ice storms and power is available at the Lexington Herald-Leader.  Comments on the article are welcome at Sustainable Kentucky.

You may want to see the first part of my slide show “Ice, Trees and Power”  Part 2 will be available this evening.

The worst ice storm in Kentucky’s history struck the state in early February 2009, wiping out power to nearly 1 million homes and businesses. In urban areas, most power outages were caused by trees striking power lines. In my op-ed piece to appear in the Lexington Herald-Leader, I argue that most damage due to ice storms could be avoided with better urban forest management.

This slide show describes the damage done to trees by the ice storm. In the second part of this presentation, I will describe how future damage can be minimized by better forest management.  (Note: For best results, please click the View Full Screen button at the bottom of the screen.

The stimulus bill includes $650 Million for Forest Service capital improvement and maintenance. Much of stimulus money will go to correct the huge backlog of Forest Service deferred maintenance. Forest Service programs to be funded include:

priority road, bridge and trail maintenance and decommissioning, including related watershed restoration and ecosystem enhancement projects; facilities improvement, maintenance and renovation; remediation of abandoned mine sites; and support costs necessary to carry out this work.

Abandoned mine lands (AML) consist of land where mining operations ceased before the 1977 Surface Mining Control and Remediation Act of 1977 became effective. There may be over 500,000 abandoned mines in the US, including nearly 40,000 mines within the boundaries of National Forests. While many abandoned mine lands are hazardous to people and the environment, they can often be quite productive when restored. It will be interesting to see how much of a stimulus the Forest Service AML projects receive. Many of these projects are ‘shovel ready’ and could employ people immediately.

Picture: Abandoned mine showing toxic water flow. Courtesy US Abandoned Mine Lands Portal

The $790 billion stimulus bill, now out in final form, does not include funding for urban forestry improvements that were in the original House version of the bill. The original bill included funding within wildlands fire management that could provide urban forestry funding:

$550,000,000… for State fire assistance hazardous fuels projects, volunteer fire assistance, cooperative forest health projects, city forest enhancements, and wood to energy grants on State and private lands

However, the final bill (available at the House Appropriations web site) now says:

$250,000,000 is for State and private forestry activities including hazardous fuels reduction, forest health and ecosystem improvement activities on State and private lands using all authorities available to the Forest Service: Provided, That up to $50,000,000 of the total funding may be used to make wood-to-energy grants to promote increased utilization of biomass from Federal,State and private lands…

Photo: Street trees in Lexington, KY. Photo by Tom Kimmerer

Flower of witchhazel, Hamamelis virginiana.  Witchhazel is the only native shrub that flowers in the winter in the eastern US. It is commonly found along streambanks and in coves and other rich, moist sites.  Witchhazel is the source of the astringent and cleansing agents sold as Witch Hazel. 

Witchhazel is pollinated by the winter moth, Eupsilia spp., which is active on warm winter days. This insect should not be confused with the non-native winter moth, Operophtera brumata, which is a harmful pest species in the northeastern US.

Sustainable Kentucky and Trees, Climate and People are experiencing technical problems. We will have both sites repaired shortly and apologize for the inconvenience.

Phenology is the study of the timing of natural events. Phenology observers record the date and location of important seasonal events, such as bud burst, flowering, insect emergence and animal migration. Once a Victorian hobby, phenology has never been of much interest to Americans. The USA National Phenology Network (USA-NPN) aims to change that by creating a network of observers, from school children to scientists, to systematically collect and report phenology data.

By combining phenology data with short- and long-term climate and weather data, scientists are better able to track the impact of climate change on the natural world. The USA-NPN was launched in Spring 2008 as a collaboration between the US Geological Survey, the University of Arizona, the University of Wisconsin – Milwaukee and Project Budburst of the University Corporation for Atmospheric Research.

The creation of a national phenology network is not only of benefit to scientists. It can help connect people with nature in a way that is useful to our understanding of climate change. Because of the technical complexity of most science, it is more and more difficult for citizens to be scientists. In the 19th century, many scientific observations were made by hobbyists. The national phenology network offers the promise of restoring the tradition of the amateur scientist.

Phenological observations are easy to make. All you need is a calendar, notebook and perhaps a ruler. The USA-NPN is trying to systematize observations by creating several projects at different levels of sophistication. Project Budburst is suitable for anyone, regardless of experience, and is especially suitable for schools. Project Budburst provides activity guides for native trees and shrubs, native flowers and ornamentals. A set of 18 widely-distributed native species, known as calibration plant species, has been selected to create an extended network of observations with sufficient overlap among observations to allow species responses across the entire country to be compared.

Anybody who is concerned about the impacts of climate change/global warming on our environment should join this effort.  For the investment of a few hours a year, you could help create a very important database that will help scientists study the impacts of global warming on the natural world. Sign up for Project Budburst today!

Picture: Red maple flowers. Picture by Tom Kimmerer

USA National Phenology Network | The Pulse of Our Planet

Is climate change bringing an earlier spring?  Article in SFGate.com

Invasive woody plants are a major problem in forests worldwide. Invasive trees and shrubs are often fast-growing with light, wind-dispersed seed or bird-carried fruit. They are able to quickly colonize disturbed sites and may prevent native species from germinating or growing. Here in central Kentucky, almost every forest patch near urban areas is so choked with bush honeysuckle that native species are not able to regenerate.

Buy why are invasive species so prevalent?  Conventional wisdom is that North America was a biological island before European settlement, and species introduced from Europe and Asia are able to establish themselves here and create conditions that allow them to perpetuate themselves.

An alternative view is that human activities do two things – bring new species into an area, and create the ecological conditions for those species to thrive. Sometimes this is easy to see. Royal paulownia (Paulownia tomentosa) and tree-of-heaven (Ailanthus altissima) are invasive Asian trees in eastern North America, but they are almost never found in mature forests. Instead, they quickly colonize areas that are disturbed by fire, plowing, or other human activities. 

Joshua King and Walter Tschinkel of Florida State University have done experiments with the exotic fire ant, Solenopsis invicta, comparing the success of this invasive species in disturbed (mowed or plowed) and undisturbed forest habitat. They found that plowing reduced the abundance and diversity of native ants and allowed fire ants to become established. In the undisturbed forest, fire ants were unable to invade the habitat of native ants.

These experiments show that fire ants are ‘passengers’ rather than ‘drivers’ of ecological change. King and Tschinkel say that fire ants and other invasive species should be described as ‘disturbance specialists’. 

If their results can be generalized, land managers may want to pay more attention to disturbance than to invasive species. Invasive species have proved difficult or impossible to control in many habitats. It may be better for land managers to focus on minimizing the kinds of disturbances that favor disturbance specialists.

Pictures:

• Paulownia tomentosa, an invasive tree, Pennsylvania Department of Conservation and Natural Resources – Forestry Archive, , Bugwood.org
• Red imported fire ant, Solenopsis invicta, Russ Ottens, University of Georgia, Bugwood.org

Articles

• Fire-Ant Invasions Are Ecological Karma, Brandon Keim, Wired Science
• King, JR, WR Tschinkel 2008 Experimental evidence that human impacts drive fire ant invasions and ecological change. PNAS DOI: 10.1073/pnas.0809423105