Global Warming & Biodiesel: Understanding the Changing Organic Soil or 'Duff' in the Circumboreal Forest & Circumpolar Barrens, Newfoundland, Canada.

[Appearing in the summer, August 2007, edition of The Osprey magazine, Natural History Society of Newfoundland & Labrador]

Earlier Osprey Discussion
This is my 5th note in The Osprey magazine concerning our most common vegetation dominated by black spruce, Kalmia angustifolia (Lambkill) and reindeer-caribou lichen (1). I condense earlier information for the general reader in a somewhat anecdotal style. If anyone would like help doing similar work in Canada or the tropics they can contact me: cowboy4444@hotmail.com, 605 Gardiner Rd., RR# North Augusta, Ontario, K0G1R0.

Introduction
By learning the geology, plants and ecology we teach ourselves to read the land as surely as we read a book or map, or learn a language, a language of landscape. The lower trunk and roots of many conifers are often buried in their own rubbish, castoffs from the living tree, needle-leaves, cones, twigs, lichen, moss, dead roots and flakes of bark. This would be like us standing in a thick layer of our own dandruff, peeled skin and fallen hair. One of the keys to understanding the huge boreal forest and circumpolar barrens is to understand the changing organic soil layer. Foresters call it duff (2). In this article I describe the spruce- kalmia barrens and organic soil behaviour and show some options for manipulation.

The monotonous spruce and kalmia vegetation generally intergrade and compete for space. Sometimes we see no spruce trees at all on the barrens and sometimes in very thick, dark spruce forest we have to look hard for a sprig of kalmia in the scant undergrowth. Most of what we do see as we drive across Newfoundland's Trans Canada Highway falls between these extremes. Kalmia is much less common in Labrador where Labrador Tea (Rhododendron groenlandicum) takes over the role as the main dwarf shrub (Day 1995, -98). Rhodora (Rhododendron canadense) mixes in with kalmia on wetter slopes and depressions in Newfoundland. Blueberry (Vaccinium angustifolium) is a most common associate, a very important food of grouse. In Europe heather plants, nibbled by sheep, dominate in similar barrens or heathlands and this introduced plant is now spreading on parts of the Avalon Peninsula, especially near Grates Cove, Conception Bay North (Day 1995).

Dissecting it: The Shrub Layer Cut like a Layer Cake
When flying at very low altitude or viewed from a facing hill one can see that the kalmia-lichen barrens are criss-crossed by trails with damaged and regrown lichen, where hares, moose, caribou and people have passed. The trodden lichen breaks when dry and is slow to regrow. These trails graphically show the intricate land use by these animals. Look for them.

If we cut through the the kalmia layer like cutting down through a cake we pass through the live kalmia shoots often mixed with blueberry shoots, dead stems of both, and then come to a layer of grey-white lichen, the caribou-reindeer lichen, mostly Cladonia/Cladina species. The upper part of the lichen layer is living but the lower part is partly decayed and it envelopes dead leaves dropped from shoots above. This lichen grows only in the moist spring and autumn and during wet weather in summer. Its flammability when dry puts the vegetation at risk. Below the lichen layer we see a layer of decaying leaves and twigs and then we are into the duff organic layer which often contains bits of charcoal from fires long ago. The duff layer ends abruptly as the organic layer builds up like a thick carpet built over the mineral soil. There is very little mixing of the two layers and this is largely due to the fact that introduced European earthworms are not active in this type of soil and do not mix the layers (3). This carpet of duff is mostly dead and it protects the mineral soil from erosive washout from rain and spring runoff.

The extent and weight of duff is truly enormous, extending from coast to coast. It holds a large part of the nutrients in the system and these nutrients are bound in woody organic matter that is very slow to decay. One barren I studied within Terra Nova Park (Ochre Hill) was over 40 yrs. old and the lichen layer and duff were particularly thick. So this mostly dead layer is the major carbon and nutrient reserve, like the dead bark and dead heartwood of trees (and dead coal and peat and petroleum), a reserve of megatons, but a very static one. A warmer global climate may accelerate duff decay or increase forest fire activity and the later could be the major factor in the decline or oxidation of world organic soils.

What Controls Natural Duff Decay in our Region?
The decay of organic material in nature is controlled by a collection of variables and in our Maritime Temperate Region the main ones relate to 1. climate: the short, cool, moist growing season, and 2. the physical & chemical nature of the duff: the acid pH, the paucity of nitrogen, the wood lignins and anti-microbial chemicals, like terpenes, hinder decay (4). Duff, and peatmoss too, are like bottled pickles and wine with their built-in chemicals and conditions (eg. lack of oxygen in peat) that slow decay. The whole thing may be described by a not so complex equation in an engineering or soils journal and I have yet to find them. Getting this data can help us predict the acceleration of duff decay with global warming. Biologists and engineers can cooperate more. Perhaps the soils courses in university Geography and Geology departments can be made joint credits with Biology. This would help. All other conditions being more or less equal it is temperature that controls duff decomposition and further south of Nova Scotia these barrens peter out.

Preliminary Analysis of Spruce & Kalmia Duff Samples at the U. of New Brunswick
This layer in kalmia-spruce forests and barrens can be 10 to 20 or more centimeters thick and is mostly composed of dead material as well as living roots and rhizomes. It is similar to peat which people commonly burn as fuel in Ireland and it can be studied in similar ways.

I brought duff samples for analysis from Butter Pot Provincial Park, to the U. of New Brunswick, 1980. Blocks of duff were cut out of the earth like squares from a cookie tray. I actually used my mothers old bread knife to do this, the best tool for the job. I was interested in...
1. density of this material (dry weight per cubic volume)
2. water content, which fluctuates but does not dry completely every summer
3. caloric content (joules), potential as solid fuel
4. biodiesel: soluble materials extractable using ether solvent (see below)
5. the percentage of the material made up by kalmia rhizomes
6. ash content (quantity of potential fertilizer & pH neutralizer)

Actual numbers are tabulated in my thesis (Day 1981) and need not be discussed here. It is enough for this discussion to say that the duff beneath kalmia is physically very similar to the duff beneath spruce trees but for the presence of rhizomes beneath kalmia. In many respects the duff layer, and peatmoss too from bogs and fens, are like cigarettes, sawdust, a stick of incense or a bowl of breakfast cereal, being mostly organic and airy, behaving physically quite differently from a much denser and heavy, compact mineral soil made up of small stones, sand, silt and clay particles. I had seen these general patterns a few years earlier after charting the small water fluctuation in the mineral soil and the wide fluctuation in organic duff beneath Diapensia, a plant of foggy rock barrens (Day 1978) (5).

Failed Duff Burning Tests at the University of Winnipeg
At the the U. of Winnipeg I collected spruce duff from nearby Birds Hill Provincial Park. The duff layer was just a few centimeters thick and I could see and feel that this crumbly Winnipeg duff had less energy, that it had lost burning power, or calories, with the faster decomposition here in the warmer, southern extremity of Manitoba's boreal forest. In the lab fume hood I ignited samples on a ceramic dish but they invariably went out after smoldering a short time. Now a match or an incense stick will do the same thing, go out, or extinguish, if placed on a ceramic plate, or a flat board or stone. Try it and see. This puzzled me until I realized that the dish, board or stone conduct heat away from the smoldering duff or match or incense, which then extinguishes. Why does this not happen in the smoldering duff on the natural forest floor and barrens? Well, in nature there is no ceramic dish. This was a flaw, or artifact, in my burning test. It is tricky to simulate natural conditions in the lab and future burning tests should have the sample sitting on a bed of duff or a similar material like fiberglass insulation. In nature the burning duff is surrounded by more dry duff or other good thermal insulators such as fragile airy ash, or air, and in nature at midday the duff is sometimes heated strongly by sunlight, and by adjacent smoldering duff. These extra sources of heat, and the insulation preventing heat loss, all contribute to the prolonged burning of natural duff. The same can be seen in a model of this behavior close at hand, a lit cigarette. It burns faster in strong sunlight or if heated by another lit cigarette nearby and it will extinguish if laid down on a hard surface that conducts heat away. Wein & McLean (1983) with other graduate students (self included), sketched a model of the way duff burns and published it. The smoldering fire in duff moves through it like a front or wall but always follows the very dry duff and stops when it meets moist duff until this has been dried off, and then ignited. The bluish smoke is solid duff gasified by heat, a cocktail of hydrocarbons plus water vapor, very much like cigarette fumes.

An Inedible Landscape can be Pushed to Greater Productivity: 4 steps
Global warming is here and active. Nobody knows how good or bad things will become. In an unpredictable future we may need to use the kalmia barrens to get through a troubled period. Kalmia, spruce, lichen and bracken fern make up what is largely an an inedible landscape. Moose will only eat spruce if nothing else is available. Sheep and deer will eventually die if given kalmia, while bracken fern is linked to stomach cancer in humans and cattle. This landscape can be pushed through simple manipulations to be much more biologically productive. The things standing in the way for naturalists or potential farmer-grazers is lack of training and will (inertia, passivity, nay-sayers). There is also ecological guilt or environmental angst. Many naturalists have not thought about this deeply but they instinctively or automatically think, then voice the opinion that the way things are is the way things should remain. This is wrong thinking. When Kalmia barrens are examined in detail, as one would examine the history or profile of an archaeological site, one quickly discovers that these barrens are largely anthropogenic, the product of over cutting and frequent fires and these barrens cluster around old European coastal settlements and the disused railway. The researchers before me, Wilton (forests of Labrador) A.W.H. Damman (forests of Newfoundland) and his student Bill Meades (shrublands or barrens) recognized this in their publications. I looked for myself and it is not difficult to find old cut tree stumps in these barrens, and dead trees and below the duff layer more fallen tree trunks and charcoal from past decades, even centuries. There is no doubt that the kalmia barrens are often the result of past human manipulations (6). Thus I see few objections to potential farmers and foresters using the science described here, and in earlier writings, to convert kalmia barrens to a mixture of plants more edible for domestic and wild herbivores. How can this be discouraged in a province where most of the food is imported and so many people are underemployed? Astonishingly, experimental trials or tests in this direction are very limited and well buried in obscure literature. It took me years to dig bits out of in-house forestry reports. The closest practical trials that have been done is the creation of community pastures around the province and the conversion of peatlands to pasture and vegetable plots carried out by Fred Rayment (retired) of Agriculture (Agrifoods) Canada, Mount Pearl. He used mechanical drainage, lime and fertilizer. I worked with him as a summer student, maybe 1977.

Were I to convert kalmia barrens I'd take the following steps. You will see it is not rocket science but akin to the slash and burn farming method that has been carried out from the Boreal Forest in Sweden to the tropics. Tropical slash and burn practices are recovering from a former bad reputation as they are being followed up with nutrient conservation additives (broken pottery and charcoal), boosted with planted legumes to form a black earth or "terra preta" (Mann 2005).

Four steps for land conversion
1. Burn the area in a dry year when the duff moisture is very low. One has to wait for the year, month and weather to cooperate and government agencies may withhold permission to burn. Unburned patches will have to be re-ignited perhaps by stacking brush. The aim is not to burn all the duff. This would be extreme and rain will carry away much ash. Sometime the goal is to burn the plants but just scorch the duff like a piece of toast. This will conserve most nutrients. Sprouting kalmia can be burned with a portable backpack burner using propane or kerosene. These are easy to make and this method is preferable to using herbicides. The burning releases nutrients (ash) bound up in the organic layer and kills many inedible, poisonous kalmia shoots and their rhizomes. The burning also reduces soil acidity, or raises pH, the ash of basic pH doing this. Locals use the folk term 'ash sweetens the soil'. Of course this has nothing to do with sugars. The blackened duff that remains after the burn is warmed earlier in the spring and this solar heat also reaches deeper into the mineral soil, encourages biological activity, soil microbes, growth of plants.

2. The Option of adding nitrogen fertilizer: Duff is very poor in nitrogen and so benefits from the addition of a general fertilizer (and more limestone powder). This stimulates decay of duff remaining after the burn. Smelly chicken manure is usually free for the asking. Waste fishmeal with pulverized seashells can be used, as can free human urine. Confined pigs or wild boar both fertilize and mix soil layers.

Supporting Lab Evidence, incubated sawdust: My students (with teacher Alan Kirby) used chicken manure in lab trials in the winter of 1995-96, College of the Atlantic, Corner Brook. We prepared large plastic buckets half-filled with moist softwood sawdust. This sawdust is very like duff in texture and organic makeup, in fact it is another good physical model of duff. It is also poor in nitrogen and thus very slow to decompose. We combined this sawdust with a small sample of chicken manure and the mixture became biologically active in the lab at room temperature, noticeably warm to the touch in a few days. The sawdust decayed, and lost mass or density over the winter term of 1996 as this decay, or slow combustion, proceeded. This is a typical soils lab technique, to incubate moist organic material and measure the rate of decomposition under varying conditions.

Supporting Evidence Seen in Nature: Fire Returns Ecosystem to Younger Stage, then Duff Decays and Loses Density
This process of accelerated decay of duff is exactly what happens when a natural fire passes through a forest or barren. Fire resets the ecosystem to a younger stage and for kalmia barrens this happens about once every 40 years, or earlier, after a lichen layer grows up and then flares in a pulse of biomass combustion. The scorched duff becomes open to the heat of the sun and fertilized with ash of basic pH (mostly calcium and silicon salts). The duff begins to decay much more rapidly, with microbial activity, and loses density and strength. I witnessed this dramatic effect at a small burned area inside Terra Nova Park. I would walk across the duff and my feet fell through the rapidly decaying crust just as feet fall through a crust over soft snow. This particular duff layer had been scorched about two summers earlier and had lost so much internal mass through decomposition that it was unable to support my 80 kilos. This is strange but true, experienced by very few naturalists.

3. Final Conversion Option
After the burning and fertilizing, barrens can be seeded with rye or oats and planted with potatoes as was common on marginal land in Boreal Europe, Russia etc. The area could be seeded with adaptable grasses and legumes, alfalfa, clover, trefoil, etc., to encourage pasture development (golf course?). Cuttings of willow, birch, currant and alder (another fixer of nitrogen), and transplants of raspberry and rhubarb also build fertility as they make a richer humus from the deciduous leaves. From this stage herbivores spread nutrients across the landscape in dung and urine. The United Kingdom and Iceland have extensive pasture and cultivated land but Newfoundland has lost a lot of what it had, through abandonment and neglect. Much abandoned pasture has grown back with white spruce (Picea glauca). The whole process of burning, neutralizing the pH and fertilizing the soil is as simple as step-wise gardening. What has held this back is the fact that the land has been kept out of the hands of the people and many leave the province. The provincial government controls most of the land, a modern form of feudalism. What a pity. This needs to change.

4. The Leave it Alone Option.
If left alone kalmia barrens accumulate more and more dead twigs and leaves and a deeper duff layer. One positive development is the growth of a deep layer of reindeer-caribou lichen. If caribou are left unmolested (as on Fogo Islands and the southern Avalon Peninsula), protected from illegal hunting and dogs they can expand their numbers and use this bountiful winter food supply. At present large expanses of lichen barrens go ungrazed by caribou as the herds are still scarce in many parts of the island. The muskoxen of north Labrador will also use this winter food. Lichen could be collected with hand rakes like hay and stockpiled as winter feed for domestic animals, a possibility. It need not be dried. This easy trial has not been tested in Newfoundland with native or exotic herbivores: hare, goats, sheep, cattle, moose or llama.

Relevance outside our Region
These studies are useful outside our region where a duff layer develops under vegetation. This can be found across much of Canada, Alaska, Korea, Hokkaido, Manchuria, Russia, Himalayas, north and alpine Europe, Patagonia, Andes, Tierra Del Fuego, Eucalyptus forests of alpine Australia and Tasmania, and even in the high mountains of east Africa, Borneo and New Guinea.

Sidebar: Biodiesel Biofuels Ecofuels
The needle-leaves and bark of conifers are full of volatile hydrocarbons too and these are used by pulp and paper factories to heat their external combustion boilers. Many people do not realize that a conifer tree is more flammable alive than dead as alive it retains the oils, terpenes and waxes that help it burst into flame. A small amount of yellowish oily biodiesel was extracted from duff in the U. of New Brunswick tests mentioned above. Canada is very rich in biofuels and the challenge is often to make this material into a gas, liquid, powder, pellet or oil-powder slurry to make it more flexible and transportable. The high energy molecules can be dissolved from the needles and bark of conifers using light solvents such as gasoline or ether then added to ecofuels or biodiesel. Industrial pressure-cooker digesters and fermentation systems of many designs are a hot topic now as world petroleum reserves runs out.
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Footnotes:
1 Others dealt with seed banks, kalmia toxins (allelopathy), flammable lichens, and exploding trees.
2 The rhizome layer is also key in marsh vegetation I studied around Ottawa (Day et al. 1988). The big aquatic bulrushes, like Scirpus american, growing at the mouth of the (degraded) Manuels River, Conception Bay, are only seriously damaged when their deeply creeping rhizomes become eroded by water or ice. The similar deeply creeping rhizomes of bracken fern are also difficult to remove from managed kalmia barrens.
3 Promoting worm activity makes more energetic-ecologic sense than using mechanical measures like rotortillers (see discussion about land conversion). It would be interesting to see how long earthworms can survive on a diet of kalmia or spruce duff, a relatively easy experiment. Ants, termites and ground squirrels, like the groundhog of south Labrador, mix soil layers in other ecosystems. Groundhogs are absent from Newfoundland, surrounded by salt water.
4 Honey and propolis, or medicinal bee resin, contain numerous anti-microbial chemicals collected from plants.
5 The big differences in the fluctuating water content when comparing mineral and organic soils is partly an artifact of the way the water content is graphed. Dont mislead yourself like I did. Water is often graphed as a percent of the soil dry weight, but organic vs. mineral soils differ so greatly in dry weight per volume that graphs are distorted. Available water is really key to understanding plant behaviour and total water per volume most important when considering combustion.
6 Historical information, personal observation of over cutting patterns (e. Briggus) & unpublished provincial forest fire maps support this statement. I am not aware of any radio carbon studies which date the development of kalmia barrens. This is neglected.
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Acknowledgement: I was encouraged in the M.Sc. thesis project by Fred Pollet, a director of Federal Forestry, St. Johns, who arranged support for the summer of 1979. This article was written in the village of Arraial d' Juda, Bahia, in coastal Brazil in the winter of 2006-7 where I made many helpful friends.

References Cited:
Day 1978. The Autecology of Diapensia lapponica in Newfoundland. B.Sc. thesis, Memorial University of Newfoundland, Biology Department.
Day 1981 R.T. The Vegetation and Organic Soil Layer in in Kalmia-Spruce Postfire Communities. U. of New Brunswick MSc thesis. [copies at MUN etc.]
Day R. T. et al. 1988. Fertility and disturbance gradients: a summary model for riverine marsh vegetation. Ecology 60: August.
Day R.T. 1995 & -98. Altas of Labrador Plants, Vols. 1 & 2. Ubiquitous Publishing. [copies at MUN etc.]
Day R.T. 1995. Dr. Paul Barclay: 1977 Newfoundland plant collection Collection [Heather in NFLD.] Sarracenia 5 (2):7-8.
Mann, C.C. 2005. 1491: Revelations of America before Columbus. Alfred Knope and Random House.
Wein R.W. & D.A. McLean. 1983. The Role of Fire in Northern Circumpolar Ecosystems. Scope 18, Chichester West Sussex, New York.