What is the correct answer for fire management in our world on our ecosystems? Fire has shaped our earth’s surface greatly and has more so since man started to shape land with it. How does continual intentional fire disturbance affect ecosystems over time? Forest ecosystems are one of the most complex ecosystems on the planet. Diversity in plant matter is not only affected by fire but so are the microbial, bacterial, and fungal genetic resources in the soil. These have an influence on ecosystem characteristics of resistance, stability, nutrient transformations, energy flow, and electrical conductivity. The microbes, as it turns out, are the first ones to colonize and multiply on the scene after a fire. Their presence, type, diversity, abundance, and recovery capacity are the conduits and determinants of the regrowth of an area. These little microbes carve the path to recovery in the soils and therefore in the ecosystem. It turns out that the more we burn the landscape, the more we burn off the diversity in the microbial orchestra that brings life back (1).
These shifts in microbial diversity, etc., have impacts on biogeochemical processes and overall ecosystem functions. Over time, the practice of intentional fires may suppress the very cure that would help the areas withstand the fires. Over time, the continual erosion of plant and soil microbe diversity weakens the areas slowly, softly suppressing the ability to be more complex higher functioning ecosystems. Soil structure diminishes, soil erosion increases, plant and insect matter decrease and pH and conductivity are altered. An ecosystem reaching for better watershed status as well as waterway and aquifer development via plant matter prosperity requires diversity and abundance in its soil structure. If these prerequisites get continually truncated with the continual use of intentional fires, there becomes a perpetual undermining process of the ecosystem. An ecosystem reaching for broader diversity, deeper top soils, fire resilience, watershed development, drawdown of carbon, and moisture to have micro-climate net water positive influence in an area needs to be ‘taken off the fire regime.’ This will improve all of the processes in the soil to engage in deeper rooted plant system growth, soil complexity and genetic diversity development, production of habitat, and potentially other food-related production.
Just as in plants, microbes have the sensitivity for recovery after a disturbance. If you think fire is all good, it might be time to rethink that hypothesis and have an honest look at repeated fire as a means to manage an ecosystem. This process is meant to remove the underbrush of a stressed eco-space where chemical breakdown of heat stress is occurring and the plants have lost their nutritional value, and are dying (or seasonally the plants are wintering off). However, potentially the key is to not let chemical breakdown begin in the first place; to create a space where there is an abundance of flora for increased creature habitat and food whereby the food supply gets readily utilized in the first place and does not go to waste (chemical break down). Instead, the area can be built up for healthy ongoing biological development and use by grazing animals. This keeps plants in an active state and less stressed (ecozone and seasonality specific of course) and the spin-off is more productivity in animal health and development. By introducing graziers as tools to the land, they enable positive feedback loops. Correct and appropriate grazing methods should be employed, including waist-high grasslands being grazed by dense animal impact over a short period of time which simulates the grasslands just enough to prosper and increase propagation. Goats, cattle, sheep, and other ungulates keep the land in biological prosperity. I would argue that if done properly, the animals stimulate the land in a way that actually causes the ecosystem to thrive, they actually help increase soil moisture retention in a space. This type of ‘animal land treatment’ gives natural fertilization, aeration, increased diversity in microbes, bacteria, and fungi in the soil, and plant species giving rise to ecosystem resilience which causes improved water content status and nutrient cycling. All these factors help in mitigation of fire in the first place.
As the world stands right now, I would argue that we have massive tracts of dormant, crusted, and underperforming land and it would be in our best interest to work with these landscapes to promote increased photosynthetic capacity, as well as soil and microbe diversity, enabling drawdown and watershed building. By intentionally recognizing the relevance in maintaining measurable and obvious natural habitats for the purposes of improving environmental productivity, watershed development and honest fire mitigation, and not to mention increasing genetic biodiversity, we will come out ahead. We have been ignoring large tracts of land, including national parks all over the world that have been essentially made impotent with poor management; we have to get more active on the land. It will take work, and we will need the understanding of compatible planting for current ecozones with the idealization of the ecosystem to change and improve the situation. The reason some plants have adapted to certain areas over time does indicate that an ecozone is well established. However, the large encrusted tracts that are ideal grassland to forest succession areas would be fantastic spaces to enact microbial and bacterial diversity and subsequent plantings of grasses, then also shrubs and trees. Not that grasslands are more important than forests; on the contrary, both ecosystems are essential. Grasslands and lightly forested areas make for very good habitats. Arguably, we need to pay attention to the soils that we are building.
There are changing forest management practices in colder climates where the growing rates are slower, we have removed fire barrier species like aspen and replanted with monoculture trees (white pine) planted closer together than historically (to create taller trees as a result of light competition). This causes the ground to change slowly over time. In these second-growth forest situations, grasslands and shrubs may not grow well enough to provide good enough food for wild animals. Biodiversity decreases, altering mineral content in the soil (makes the soil too salty or too mineral-deficient), affecting soil conductivity which affects plant growth. Another recipe for fire, desertification, habitat degradation and/or loss of important genetic resources.
Sandy soil is a poor conductor of heat and electricity due to the lack of minerals and structure that would hold moisture that would enable conductivity and the downward flux of heat to enable plant growth. When sunlight hits sand (which is essentially comprised of silica), most of the energy of that sunlight is absorbed within the first millimeter and it only penetrates a few millimeters down; these few millimeters can get quite hot. There is nothing else in the soil structure that enables the transfer of electrical energy or moisture properties downwards to enable plant growth. Essentially, the soil battery dies. If regular fire is inhibiting the proliferation and diversity of microbes and therefore other interdependent elements in the soil, it is only a matter of time before the desertification process starts to happen. Or at least the crusting process as geologically, there are areas that have higher silt and/or iron-rich soils that are still poor soils if left unintegrated with greater organic matter. Geologically speaking and with understanding sunlight and drainage variability in the soils, we should be able to figure out sensible soil deliberations. If we are sprouting tree sprouts all over the place, we need also to understand the success appropriation of the inherent co-development of soil structures to tree and grassland propagation. For example, in contrast to sand, a higher clay content soil would have much higher water content and be a better conductor of electricity and heat thereby enabling different (better) growth opportunities.
And so it remains that microbes are so necessary for our life serving landscapes. They are like tiny factories helping to regain the properties towards life propagation. They help bring the dirt into action. Dirt without water content is not a good conductor and not good ground as the minerals elements in water are key to conduct the electricity. Conductivity has been found to influence electrical fields and magnetic fields, again all linking the overall vibrancy of an area. Electrical conductivity levels in soils range from 110-570 milliSiemens per meter (mS/m). While too low of a level indicates low available nutrients and too high electrical conductivity levels indicate an excess of nutrients.
Understanding the electrical conductivity (EC) in soil is a prerequisite to the understanding of the soils ability to transmit heat, sound or electricity. As well as the understanding of pH. EC is a measure of how easily a material permits the flow of current. This is a part of understanding the total dissolved solids (TDS) which is measured in parts per million (PPM) derived by a calculation out of the EC value. If the solution has a higher [H+] concentration this means a lower pH, while lower [H+] equals a higher pH.
So now the interrelatedness of fire, soil microbes, moisture capability, organic matter development through biological breakdown of biomass, and electrical conductivity and pH in the soil should be apparent. Again, geographically speaking, understanding what is and what could be are processes of learning how to build soil by helping, transforming, and bringing it into a better state of being.
Electrical conductivity affects plant growth as when there is higher osmotic pressure around the roots, as a function of soil and moisture structure and this prevents efficient water absorption by the plant. So all characteristics of microbes, soil pH, organic matter and heat transfer down into the soil affect plant growth.
Not all fires are equal either, some burn hotter and longer, some are more patchy as a result of different fuel loads, slope and vegetation types, frequency, moisture and temperature in the area. And over time, prescribed burning may have more long term negative effects on the microbe and soil structures than the more intermittent wildfires (1).
When looking at ecozones on the globe also, one has to remember that latitudinally, the sun will hit the surface of the earth in predictable ways causing certain types of ecological patterns to occur. Identifying these patterns is helpful when trying to determine suitable land management ideals in the process of trying to shift plant community structures towards better ecoscapes either after a fire, or to build up resistance against fires. Turning a desertified and formerly barren landscape into a life-giving watershed will require thorough analysis and planning, not to mention a good ten to thirty years to really leave the land in positive legacy shape. After a forest fire, sprouts can come back quickly, but a real tragedy is not fully understanding the implications of what we are doing with our forests overall and not taking in the consequences of how we allow our landscapes to become more and more barren. And also not recognizing the consequences of also losing more genetic diversity from microbes to trees and animals. Paying attention to the honest possible lifespan of trees also makes for wise management as, trees at different areas on the globe do have different longevity, with some known to age to 1000 years old or more while others maybe not so much. We need to pay attention to the trees that we want to nurture through to older ages and recognize how we are potentially damaging ecoscapes too much with our use of fire instead of correctly using animals to ‘pare the land’ for both the biological fruits the land is baring and also to pare the land in response to adaptive fire management and biological prosperity.
There are above ground effects and below-ground effects of fire on ecosystems and we are just beginning to learn the deeper effects of fire management on landscapes not to mention learning also the simultaneous opportunity to build up watersheds. Over time, it seems counter-intuitive to use fire as a means to land management prosperity. Certain situations may prevail wherein intentional fires are potentially a more effective means of helping to improve a challenging landscape. However, we are essentially just beginning to understand and create critical mass on truths that benefit soils and ecosystems towards growing biomass, increasing a land’s photosynthetic capacity, and the implications of moisture drawdown and rainfall circulation as a result of such biomass cultivation. The ability for us to build our landscape structures, improve productivity, prosperity and the lands well being depends on the advancing development of all of this knowledge. We are very much just scratching the surface on understanding a landscapes’ true potentials and their true prosperity.
Shen, J.- et al. Long term repeated fire disturbance alters soil bacterial diversity but not the abundance in an Australian wet sclerophyll forest. Sci. Rep. 6, 19639; doi: 10.1038/srep19639 (2016).