Living Lighter on the Land
With lengthening days, we are living lighter on the land this month by harnessing the power of the sun. In our cold frame, thickly insulated with hay and oriented to receive maximum light, the plants are growing so quickly that I have begun to harvest extra greens for our chickens. The girls have rewarded us in turn with up to four eggs a day (from 4 laying hens), and are churning through our compost in search of what bugs are active in March. Next month, I will introduce to you our new and improved solar array, powering the Armstrong Education Center at 100%!
In the Armstrong kitchen, we ate salad from the cold frame all winter long with the exception of a few weeks in January (see Early 2014 North American Cold Wave). I went out often to brush off snow but didn't dare open the door, as I could see though the frozen condensation that the plants were wilting at their tips. The greens pictured here were planted as seed in October: Cavolo kale, Spring broccoli raab, Mizuna, Rossimo lettuce, Red giant mustard, Speckled lettuce, and Renegade spinach. A few Red chard transplanted in have not fared well. The Mizuna and lettuces recently began flowering and so were cleared out to make room for kale and spinach that had somewhat languished beneath. We should have greens for months yet.
The cold frame is serving double duty as our germinator and seedling incubator too. So far, I have started Utah tall celery, Curley parsley, Common chives, Clear dawn onions, Broccoli, and Long Island Improved brussels sprouts, in addition to native species Bladdernut and Groundnut. For most plants (especially New York natives), temperature is not the limiting factor so much as light, and only the sunniest of window sills are adequate. I find it easier, and a lot cleaner, to set up my grow space outside or in a basement/workshop area under lights. LED lights are most efficient, but must be in the correct spectrum for plants to use the light.
See how we grow vegetables, flowers, and native trees and shrubs in the Armstrong Working Backyard our May 3 Plant Swap and Volunteer Work Session. To get started sooner, click here for instructions on making a cold frame and starting seeds. See also our lineup of events in our partnership series Birds & Bees: Wildlife Needs, aimed at educating our community about the role of native plants to native wildlife, including what you can do to foster their habitats on your own property!
If you haven't started planning for this year's garden, now is the time to begin! Nurseries and serious gardeners have already started sowing under lights, and by the end of this month, we can often plant spinach, radish, and sugar snap peas here in New York. Taking some time now to plan what, where, and when you will plant can save you work in the long run and increase the useful yield of your garden. By timing crops to mature in batches, for example, you can produce abundant harvests from May to November, and even beyond with help from a cold-frame or other frost protection.
We recently hosted a Garden Planning Workshop at the Armstrong Education Center, the center of our public programming for education on Living Lighter on the Land. In case you missed it, I will present here some of the material we covered and will also direct you to a webpage I created which serves as something like a resource library for topics covered at PRLC workshops: Land Stewardship in Action Wiki. Feel free to copy the Wiki and add to it for your own purposes.
We covered the basics outlined below and then expanded our conversation based on the specific cases presented, such as fertilization for raised beds that are filled with coir and perlite rather than soil and compost (probably best to take a soil test first). Events like this are a great place to have your specific questions addressed by a group of knowledgeable people. Please see the events calendar on our website for information about our May 3 Plant Swap and Volunteer Work Session, and stay tuned for a planned series in April and May that will teach you how to provide quality habitat for local wildlife using native plants, trees, and shrubs on your property (and get Certified for your efforts by the National Wildlife Federation).
Garden Planning Basics:
- Prepare the soil. It is important to meet the needs of whatever plants you wish to grow, but drastically amending soil can be costly and time-consuming. (link for soil testing services)
- Decide what you want to grow. My advice is to dream big and then whittle your list down according to how much space and time you have. Put everything else on a vision board for later inspiration.
- Map your planting areas. Note the soil and light conditions, and choose plants with similar requirements. Consider planting "companion plants" that grow well together. Some gardeners plan for height variation or for "seasonal interest." I make multiple maps for early season, mid-season, and late season.
- Schedule planting and other tasks such as feeding, mulching, and harvesting. Remember that as some plants reach their harvest point, others can be sown beneath for repeat harvests all season long.
A List of Gardening Tasks for Early Spring:
- Gather materials: Seeds, trays, leaf mold or other sowing medium
- Turn the compost pile so that it is ready when you need it
- Turn the leaf pile to speed up its composting
- Build a trellis for peas
The week starting Feb. 28, under protection, plant onions, leeks, scallions, chives, celery, celeriac, artichoke.
The week starting March 7, under protection, plant all of the above plus arugula, spring raab, and parsley
The week starting March 14, under protection, plant all of the above plus lettuce, early cabbage, kale, collards, broccoli. Direct sow spinach, peas, arugula, and spring/summer onions.
The week starting March 21, under protection, plant the above plus peppers, tomatoes, eggplant, chard, bok choy. Continue to sow plants listed through April.
The week starting March 28, direct sow spring raab, radishes, spinach, peas, arugula, and spring/summer onions
The week starting April 14, direct sow lettuce, carrots, parsnips, spring raab, radishes, spinach, peas, arugula, and spring/summer onions. Transplant lettuce, parsley, scallions, and chives.
The week starting April 28, direct sow chard, beets, lettuce, carrots, parsnips, spring raab, radishes, spinach, peas, arugula, onions. Transplant early cabbage, kale, collards, broccoli, tatsoi, bok choy, arugula, lettuce, spring raab, parsley, chives
To be continued…
In the northeast, home heating is the largest residential energy expense and accounts for up to half of all housing-related carbon emissions. How can you, the conscientious citizen, stay warm in winter without leaving your environmental concerns out in the cold? Answering this question is a top priority at the Pound Ridge Land Conservancy’s Armstrong Education Center, where I live and work out of the Armstrong House, an older home retrofitted with cutting-edge technologies to be a model for low-impact 21st century living. Former Living Lighter on the Land blog posts have covered green energy topics including the costs/benefits of wood heat (March 4, 2013) and radiant heat (Dec. 19, 2012). In this edition of the blog, I will explore some of the options for efficient home heating with recommendations from my own experience at Armstrong.
No matter what energy source you use, the first and most important thing you can do to limit consumption and pollution is to insulate and air seal your home. Caulking and weatherstripping are simple and cost-effective ways to get started. According to the Alliance for Green Heat, heating results in an average of 345 million metric tons of carbon each year, whereas air conditioning, the second largest sources of emissions, accounts for about 147 million, both of which are reduced by investments in home insulation. It pays for itself too – insulating your home can lower energy bills by up to 50%. Renovations at the Armstrong House included the spraying of soy based foam insulation in the walls and ceilings and extensive sealing of cracks and energy leakage points like power outlets. We also installed a low emissive reflective insulation and housewrap. The goal is to create a continuous thermal barrier envelope that reduces air exchange and conductive heat loss. Remember that better quality insulation has higher R value (or thermal resistance), regardless of thickness. Options include spraying insulation from the inside, through holes in the walls, but better coverage is achieved by removing the siding on the outside. In the photo below, notice the dark areas on the roof where snow has melted. These are indicative of heat loss due to a discontinous thermal barrier.
One simple piece of technology to consider for your green home is a heat exchanger. We have a ventilation-specific heat exchanger on our air filtration system at Armstrong that is 70% efficient. This means: In winter, cold air from the intake pipe is first heated by outgoing air before it circulates through the house. In summer, the heat from warm outdoor air is removed by the outgoing exhaust stream. The two air streams remain separate throughout.
No matter what source of energy you use, the above suggestions can help to lower your costs and emissions, which is often more feasible for the homeowner than converting to another heat source. However, adding a wood or pellet stove to your existing system can be a sound investment. I am going to put my neck right out there and say that I am a fan of heating by wood. Not only does it lend a wonderfully cozy feeling to one’s home, it gives one the excuse to get outside and take a breath of fresh air while loading up an arm’s worth for the day. Controversy over wood burning’s contribution to air pollution seems to be dampened by arguments for its overall benefit to local economies and a reduction in the amount of oil and gas being transported from a distance. Plus, there has been a lot of progress in stove efficiency, prompted in part by a contest and partly by pending legislation from the Environmental Protection Agency, which proposes new standards for efficiency for stoves sold after 2015.
The Wittus Twinfire is an award-winner made by the same local company that generously donated our stove at Armstrong: it has an efficiency rating of 93% and can reduce wood use by 40%. The secret is called two-stage gasification: it heats wood in one compartment in the relative absence of oxygen, releasing combustible gases into a separate compartment where they meet air and efficiently release their energy with very little emissions.
We have burned about a cord and a half of wood in our stove this winter, and we harvested it from storm-blown trees on the property with the help of volunteers. Conservatively speaking, the heat produced by burning that amount of prime oak in our stove is equivalent to burning about 200 gallons of propane (our current fuel for the radiant heat system, until our solar thermal panels are installed). In other words, we have saved $600 by using wood this season and can expect to double that by the time winter is over. Use this handy fuel comparison chart to figure out how much you might save. Keep in mind that prices vary regionally, and that seasoned wood yields more energy (and less pollution) than freshly split, “greeen” wood. Cornell Cooperative Extension can help you to make the transition to wood burning and advise you on safety and maintenance of your wood stove, pellet stove, or boiler. They can also help to advise you on how to manage your woodlot for sustainable fuel harvests.
Brrr! It's cold outside. The Chickadees are as puffed up as they can be and are staying close by their caches of energy-rich seeds and berries. Chickadees will forage and add to their stores as winter progresses, providing hours of entertainment for an attentive birdwatcher. They and other small songbirds need to eat the equivalent of more than 10% of their bodyweight daily just to make it through each night. Perhaps for this reason, a number of birds congregate together in winter in what are known as "mixed foraging flocks" – Titmice, Juncos, Nuthatches, Creepers, Kinglets, and Downy woodpeckers join the Chickadee in sharing food resources while warning of potential predators. Where are all the other animals of winter? Should we be concerned for their welfare in this cold?
On the whole, any animal that makes this region its home is adapted to the extremes of temperature. For example, birds have circulatory systems that separate the cold blood in their legs from the rest of their bodies. The heartbeats of turtles slow to about one beat per minute, and even those living under ice can draw in oxygen through the cloaca. Frogs can freeze and thaw, and some insects produce antifreeze proteins in their blood. The honey bees in our hive at the "Working Backyard" demonstration site at the Armstrong Education Center do not hibernate but instead cluster together in a humming mass to maintain adequate body temperature. They feed upon their stored honey to obtain the energy needed for this near constant activity. With honey bees in precipitous decline, we opted not to harvest any of the sweet stuff for ourselves this year. (For more information, stay tuned to our Events Calendar, including a showing of the documentary "Vanishing of the Bees" on April 11).
The availability of winter food is a good predictor of which animal species hibernate and for how long. Insectivorous bats, grass-loving woodchucks (also known as groundhogs), and fruit-loving chipmunks will all sleep until Spring has sprung. Many more animals lie dormant for short periods and rise to forage on warm days, including skunks, squirrels, beaver, muskrat, and bear. Mammals that do not hibernate, like the Eastern coyote and White-tailed deer, must eat enough to maintain internal body temperatures similar to our own and are therefore surprisingly active in winter and more generalist in their diets. You have probably noticed that deer will eat just about anything vegetative. Coyotes eat a lot of fruit and rodents in addition to young deer. Thinking about the habits and living conditions of the animals sharing our landscape enhances ones connection to place and to the interplay of life, and is increasingly advocated as part of basic childhood education. For conservationists, tracks provide invaluable information about the distribution and health of animals and their habitat use.
I have taken much pleasure in following the tracks of a Red fox around Armstrong Preserve this week, with fresh prints daily leading to new insights about my secretive neighbor, whom I've never actually seen. I am touched by the play of its softly furred prints across the stark frozen surface of the Croton Reservoir, and the way each rear footfall is carefully placed to "direct register" over the preceding one. Tracking is an art and a skill that I have yet to fully develop, but as with most worthy endeavors, the joy is in the work, or in this case the journey. World-famous trackers Tom Brown Jr. and Susan Morse say they have never stopped learning so long as there is a track to follow.
Perhaps you have a local wildlife observation to share. Send me an email, or better yet, join Pound Ridge Land Conservancy this Saturday in welcoming Chris Nagy of the Wild Suburbia Project to the Armstrong Education Center Workshop Series. Chris will share with us Wild Suburbia's successful citizen science project documenting the presence of five large mammal species in Westchester County and surrounding areas.
Winter is here and with it come sightings of some extraordinarily beautiful visitors to our lands and waters. While it is true that most birds migrate south to warmer climes and richer feeding grounds, incoming migrants are just arriving from the Arctic and points north. The Hudson Valley E-Almanac last week reported an irruption of Snowy owls in our area and the rare presence of a Greater white-fronted goose, which had gotten off course when leaving the tundra and found itself amidst a flock of Canada geese. Late season migrants are generally larger-bodied birds, able to take the cold and to take advantage of available prey, seed stores, and habitat niches.
The open waters of our reservoirs are prime winter duck habitat, and clear sight lines make the shore particularly rewarding for viewing the bold breeding plumages and even courtship behavior of more than twenty different Anatidae species (see Audobon's list of birds in Westchester County). On a recent outing at the Cross River Reservoir, which is accessible by trail from both the Armstrong and Richards Preserves, I noted a raft of four Hooded mergansers and separately, a group of Buffleheads and Mallards with one Common goldeneye. From now through February I can expect to see many more, including the lovely Ring-necked duck, Canvasback, Lesser Scaup, and others, which sometimes raft up in the hundreds or even thousands. Were I to venture over to nearest salt-water shore, I might find spectacular seaducks like Common and King Eider, Harlequins, and Scoters bobbing in the surf.
Most of the birds I have mentionnned thus far would be termed "medium distance migrants," because they are resident year-round in North America and move on a predictable, seasonal rotation. True long-distance migrants are rarer and include the Artic tern and Whooping crane, along with a number of "our" small songbirds which actually spend the majority of the year in the neotropics and thus only summer with us here. Of course, some birds don't migrate at all, such as the familiar Northern cardinal, Downy woodpecker, and Black-capped chickadee. They rely on a local abundance of seed, fruit, and insects to sustain them through the winter, and will move short distances (a few hundred miles) if food becomes scarce.
Bird-lovers, hunters, and scientists have come up with various methods to predict the arrival and departure of each species in an area. One of those methods is based on a Cumulative WSI (Weather Severity Index) = – [average daily temperature oC ] + number of consecutive days with average temperature <0 o C + snow depth + number of consecutive days with snow cover. I recommend checking in with the E-Almanac or your local Audobon chapter for recent sightings. We happen to be smack in the middle of the 114th Annual Audobon Christmas Bird Count, an inventory of birds seen by backyard birders from all over the world. Sign up for a New York observation site here, and happy ducking!
I would bet that anybody reading this blog considers him or herself a conservationist, a steward of the land and waters supporting life on Earth. My job as Land Steward for the seventeen parcels protected by the Pound Ridge Land Conservancy is as varied as this landscape, and yet there are common threads that tie together this work and connect to other's efforts to protect plants and wildlife, including your own. In order to survive, all plants and animals need habitat: places to eat, sleep, reproduce, and withstand extreme climate events. They need connectivity between habitat, either as safe passages for travel or for gene-mixing to occur through reproduction (prolonging the long-term health of a species). Our main job as conservationists is to maintain the health of native landscapes so that habitat and connections exist to support the web of life on which we all depend.
Increasingly, my time on the land is taken up with control of plants and animals that are newcomers to our landscape. Not all non-native species are a cause for concern, but those that are classified as "invasive" threaten the health of ecosystems when they out-compete native species and alter the composition of communities. Species that are invasive have the potential to affect food webs and habitats in dramatic and irreversible ways, which is why conservationists worldwide are concerned about the increased mobility of organisms into and out of ecosystems that were previously more "closed" by natural barriers of time and space.
Even species that are technically native to our country as not necessarily desireable in the local landscape, which comes as a surprise to most people, who are accustomed to thinking in terms of political and state boundaries rather than ecological ones. The plants and animals in our community have adapted to one another and to prevailing environmental conditions through eons, and are unlikely to benefit from an influx of new genetic material in the system. In the case of plants especially, specially-raised cultivars can pollute the gene pool of local plants, impairing their ability to serve the animals that have co-adapted to depend upon them.
A prime example is Giant reed, or Phragmites, a local species that has been corrupted by genes from its cousin (native to the Pacific Northwest), resulting in an aggressively spreading rootstock that monopolizes wetlands and vastly reduces biodiversity. It is nearly impossible to find the local and non-invasive variety of Phragmites today. We have been working hard to combat its spread at the Isaacson Preserve, home to a globally rare fen habitat that still holds a healthy and specialized community of plants, insects, and birdlife. Even in PRLC's small protected preserves, life succeeds by adapting to changing conditions we have little control over and which are often too complicated for us to fully comprehend. What we do know is that native species and landscapes are resilient, and that many if not most of our native species can succeed with careful management and remediation of human impacts.
PRLC has been working with numerous local conservation partners to devise a strategy that will limit the further spread of invasive species into sensitive areas. You can help (and learn more) by staying tuned to this blog and by joining us at our Volunteer Work Sessions on the first Saturday of each month (10am-noon). At home, you can help wildlife immediately by replacing nursery-bred cultivars with native species (find out how here, and soon, on our website). Encourage your local municipality to do the same, using New York City as an example of a community that has outlawed the planting of non-native genotypes on city streets in order to protect wildlife in the city and beyond. We are all connected in today's world, and we must work together to protect the integrity of native landscapes to support local flora and fauna, or lose it forever.
The Armstrong Education Center garden reached its peak in early September with an abundance of beans, squash, tomatoes, and okra. Okra you say? You should try it! The plants are vigorous growers with gorgeous red stalks and broad green leaves in tiers. They make a semi-porous hedge over 6 feet tall by October. Ours conveniently hid the tomato plants as they withered and browned and yet allowed plenty of sun through to redden the fruit. Okra makes a beautiful flower too, with large creamy petals around a dark chocolate center. Our bees visited them often.
The success of our garden depends upon bees and other insects to pollinate what plants are not wind-pollinated. Speaking of wind-pollinated crops, corn was a disappointment in our garden this season. Dryness, wind, and climbing bean vines conspired to pull down many of the corn stalks in our Three Sisters plot. Note: Next time, I'll reinforce each mound with a tall stick deeply set in the center to which the stalks can be tied. One of our great surprises was the large yellow pumpkin that can be seen in the photograph above among the okra plants. It must have come from the Great Pumpkin, or more likely as a volunteer from our compost pile. We receive a quantity of compostable vegetable matter from Scott's Corner Market, our local grocery store, and I believe our fabulous melon crop also came in from the market. It's a win-win situation, recycling what is usable and with the benefit of golden, juicy canteloupe in addition to enriched soil.
Our garden also depends upon the support of the community and volunteer help, and we have been lucky to have a volunteer from Fox Lane High School extend her summer internship into fall. Alizah helped us to harvest all season, to keep the plants productive, but recently that takes up the majority of the time we have gardening. There are potatoes to dig, beans to shell, herbs to dry and leaves to wash. It's a good thing she got out in early August and planted our fall garden: mainly roots and greens. We also planted some cover crops of crimson clover in areas that were ready to be cleared (photo on right). All we have to do there is occasionally water and watch the slow progression of plant growth in fall. When the clover is about eight weeks old, we will turn it into the soil as a green manure to aid next year's vegetable crop.
Indoors, we've used a number of methods to preserve some of our bounty. Tomatoes have been frozen, cooked and jarred, dehydrated, and served in all manner of dishes from breakfast to dinner. Zucchini have been baked, broiled, grated, and steamed (they store better when pre-cooked). We have jars of pinto beans and a pantry full of oiled winter squash (the oil retards fungal growth). We even have apples from our tree, which we store apart from other produce because of their tendency to promote ripening. Stay tuned to our events calendar for future workshops on canning and other methods for preserving the fruits of your labor.
As a final note to our fall garden program, we set up the cold frame just this week. It is oriented to receive the most of our winter sun and is insulated with hay and foam from another project. With seed donated by the Pound Ridge Nursery , we should be able to grow greens through the winter. We are ever mindful of resource consumption here at Armstrong, and by growing our own vegetables at home (year round!) we model one easy way to live lighter on the land. It's also great for your body, delivering a fresh complement of nutrients to your every meal. Happy harvest!
The start of Autumn brings me a chance to reflect upon our busy Summer of gardening, field work, and internships at Pound Ridge Land Conservancy. Our programs of land protection and education depend upon the hard work of many helping hands, all of whom are learning to live lighter on the land. We received a grant from a local gardening club, Rusticus, that helped us to sponsor three wonderful summer interns. I will briefly summarize their projects here, along with the work of several volunteers who put in time and effort supporting our goals at PRLC. Stay tuned to our website, www.PRLC.net for greater detail on their accomplishments.
Tuddy (pronouced Too-dee) came to us from Columbia University Graduate School and completed an internship in Native Landscape Design. Her work was based at the Armstrong Education Center, where she analyzed site conditions and researched local ecology to find what plants would work best here to further our goal of establishing native plant gardens that benefit wildlife. She designed plantings for five micro-sites that can be used to educate other area landowners about how to augment the conservation value of their property, without attracting more deer. The over-abundance of deer in our area has resulted in decreased availability of food for other forms of wildlife, and Tuddy's plans address that issue with elegant style. Her designs do not require fencing and showcase plants with varying seasonal interest for humans and animals alike.
Nick grew up in this area and studies plant ecology at College of the Holy Cross. He conducted a baseline assesment of the vegetation community within our proposed deer-exclosure site at the Armstrong Preserve and documented seasonal change in the meadow community at Clark Preserve. Nick's meadow study plots were inadvertantly mowed by the landscaping crew of a helpful and supportive neighbor, but he responded adaptively, as did many of the plants in the meadow, making for a true learning experience. Nick's work will serve as a reference and guide for future projects to be completed at our preserves and on private properties with conservation goals.
Alizah is a rising senior at Fox Lane High School and has a vital interest in sustainability along with a strong work ethic. She provided consistent support in our organic garden, helping with planning, mapping, seeding, weeding, harvesting, and bug-control. She turned our compost and added it to the young and growing plants, watered when it was dry, and enthusiastically shared her learning with visitors to our garden. Alizah's interactive garden map will be used to plan next year's rotation of spring, summer, and fall crops.
Volunteers Kadijah, Scott, and Luke assisted in all of these projects, filling in the gaps to carry us successfully through the summer. Kadijah comes from an urban background and relished her time in the garden, absorbing information with spot-on precision. Scott is intent on learning the ropes of preserve stewardship and continues to provide invaluable help with meadow and forestry projects. Luke gained knowledge of landscape preservation in his hometown and helped to spread the word about our projects and the many events we host.
What is the common denominator that drives these young people's efforts? They are motivated by a desire to serve something greater than themselves, to provide for the greater good of their community and the larger world. Several of them were involved in the Boy Scouts of America as youth, and some continue to be and wanted to pass on this inspirational message to our readers:
"In addition to teaching kids about basic plant and wildlife identification, Scouting engages youth to make the smallest impact possible on the outdoors, to respect the life they encounter, to understand the man aspects of a healthy and balanced ecosystem, and to take the initiative in taking care of the environment in and around their communities. This summer, Pound Ridge's Scout 'Guy' completed a personal service project that earned him the rank of Eagle Scout, an achievement requiring hundreds of hours of service and self-directed commitment. He erected an information kiosk on the Armstrong Preserve that will serve to educate visitors for many years. Three of our other summer interns/volunteers were set on the path of environmental service through scouting and count their experience as a strong impetus for current engagement in conservation efforts. The excellent work done this summer by volunteer Scouts is a testament to the core values shared by these two organizations, and the magnitude of an effect thay have on young people."
I would like to express my sincere appreciation for the help of all our volunteers and interns this summer. I wish them the very best in their future endeavors within our community and beyond.
It always comes as a surprise to me that the first signs of Fall appear now, at the end of August. Sure, we can expect some more hot days, maybe even an Indian Summer, but the leaves are thinning out and beginning to drop already. You may sense a change in the light, which our trees respond to by ceasing production of chlorophyll in their leaves, revealing to us the brilliant colors of fall. Many of us wait for this time of year to find our favorite trees: we seek the red of oaks and cherry, the yellows of ash, hickory, birch, and poplar, or our real stunner, the red-orange-yellow leaves of the Sugar maple. I invite you to join me in practicing your tree identification skills on a Guided Walk and Talk in one of our most beautiful protected forests, the Richard's Preserve on Saturday, October 19, from 10am to noon. You can find information about other guided walks, and other preserves to visit, on our website www.PRLC.net.
You don't need to wait for the leaves to turn to start looking at trees, however. I have recently become fascinated by an aspect of trees that can be studied year-round, and with many stories to tell: their bark. Be it flaky, shaggy, craggy, or peeling, bark is an integral part of a tree's structure, much like the skin on your body. It serves to protect the trees delicate inner layers, where sugars and nutrients flow from roots to tip and back again. Native Americans used the bark of several tree species as powerful medecine, as well as for shelters and canoes. Bark can also help us to identify a tree's species, for every one of our 60 or so species here has a distinctive look that a trained eye can discern. This is especially useful in winter, or when the tree canopy is so high that we can't make out leaf shape.
The evolution of tree bark into its many forms is due to the particular pressures that tree species encounter, or once encountered, in their ancestral habitats. For example, the peeling, papery bark of birches is easily shed to rid the tree of epiphytic plants and mosses that tend to accumulate in the fog-shrouded forests where birches thrive. In areas that are prone to fire, trees like the Pitch Pine grow thick bark at a young age to survive searing heat. While thick bark serves to also deter many of the insects and fungi that parasitize trees, it also limits their expansion somewhat, and impedes photosynthesis. Some trees, like Beech, do photosynthesize through their thin bark, and this gives them a head-start on leaf-out for the summer. It also means that initials and such that are carved into Beech bark can last for the life of the tree, or hasten its demise by allowing entry of tree-killing pathogens.
Trees other than Beech respond to wounding much like your skin does, by growing a thicker layer over the wound. Study the scars on an old tree and you might find that it has withstood damage from hurricanes, fires, wire fencing, and even bear and buck rubbing. Buck will rub their antlers on trees to help them shed their velvet. With the overabundance of deer in southern New York, we find an abundance of Sugar maples afflicted by disease that enters through their wounded bark.
In a healthy ecosystem, bucks and trees can coexist because of a natural balance, the same balance that keeps insects and fungi from killing the trees they need to live on. Human impacts have altered our forest ecosystems in the Northeast to such an extent that equilibrium has been lost. We now face the imminent loss of a number of cherished tree species, including Ash, Beech, and Eastern Hemlock, due to invasive insects that have surmounted the protective layer of bark and tunnel within. The top recommendation for controlling the spread of such invasives as the Emerald Ash Borer, Asian Long-horned beetle, and Hemlock Woolly Adelgid is to never move firewood across property boundaries. Campgrounds such as Ward Pound Ridge Reservation now provide firewood as a deterrant to transporting it. To report a sighting of an invasive insect in New York, or to learn more, click here.
For more information about forestry, trees in general, and bark in particular, I highly recommend Northern Woodlands magazine, published quarterly by the Center for Northern Woodlands Education, Inc. I can't rave enough about what an excellent resource this has been in my own education and teaching career. Many thanks to Michael Wojtech, whose 2011 article on bark inspired me to look upon it in a whole new light.