Watershed Response to Western Juniper Control
Timothy L. Deboodt. 2008. Watershed Response to Western Juniper Control. Dissertation for the degree Doctor of Philosophy in Rangeland Ecology and Management, Oregon State University, presented on May 8, 2008.
Full text [here] (4.6 MB)
Abstract:
Western juniper (Juniperus occidentalis) encroachment has been associated with increased soil loss and reduced infiltration resulting in the loss of native herbaceous plant communities and the bird and animal species that rely on them. Hydrologically, however, change in water yield has been linked with the amount of annual precipitation a site received. Studies published in the 1970’s and 1980’s, suggest that a minimum 450 mm (18 inches) of annual precipitation was necessary before an increase in water yield manifested itself following vegetation manipulation.
In 1993, a paired watershed study was initiated in the Camp Creek drainage, a tributary of the Crooked River of central Oregon, to evaluate the impacts of cutting western juniper on the hydrologic function of those sites. The study involved a paired watershed approach using watersheds of approximately 110 hectares (270 acres) each to evaluate changes in a system’s water budget following the reduction of western juniper.
The 30 year average annual precipitation for the area is 350 mm (13.75) and during the study period, annual precipitation ranged from 80 percent to 129 percent of average. In 2005, following 12 years of pretreatment monitoring in the 2 watersheds (Mays and Jensen) all post-European aged juniper (juniper < 140 years of age) were cut from the treatment watershed (Mays).
Analysis indicated that juniper reduction significantly increased late season spring flow by 225 percent (alpha > .05), increased days of recorded ground water by an average of 41 days (alpha > .05) and increased the relative availability of late season soil moisture at soil depths of .76 m (27 inches) (alpha > 0.1).
Reconstructing the Fire History of the Jarrah Forest of south-western Australia
David Ward and Gerard Van Didden. 1997. Reconstructing the Fire History of the Jarrah Forest of south-western Australia. A Report to Environment Australia under the Regional Forest Agreement December 1997.
David Ward is Senior Research Scientist, Department of Conservation and Land Management (CALM) in Western Australia and Visiting Senior Research Fellow, Curtin University, Perth
Gerard Van Didden is a Retired Department of Conservation and Land Management officer
Full text [here]
Selected excerpts:
Introduction
… The jarrah forest is a complicated system, involving humans for thousands of years. Anthropologists tell us of the importance of fire in Aboriginal culture, and there is historical evidence in the letters and journals of early European explorers of south-western Australia that fires occurred as frequently as every 2-4 years, at least in some parts. …
This study reconstructs fire history from marks on the stems of grasstrees (Xanthorrhoea spp). This information meshes with the broad perspectives of history and anthropology, giving a framework within which we can link the concerns of biologists, soil scientists, fire fighters, and managers. In turn, the framework can be used to create a map of consciously linked research questions, relevant to management of the jarrah forest. …
Methods
Grasstree (Xanthorrhoea spp) stems were cleaned with a grinder, so exposing cream and brown growth rings (Ward 1996), which match with internal growth bumps (Lamont and Downes 1979). The grinding also exposed some bands of dark pigment in the old leaf bases. These dark bands occurred consistently at points on the stems where fires were known from CALM records to have occurred; and where fires were likely to have occurred, since the grasstree had flowered at that point. …
Xanthorrhoea thorntonii. Photo courtesy Department of Conservation and Land Management [here]
Some leafbases were carefully removed, washed in alcohol, and cut into 1 centimetre pieces measured from the proximal end. The length of leafbase can vary from tree to tree due to burning away by past fires (Drummond 1847). In this case each leafbase gave 5 pieces. Each year showed the twin band of cream and brown leafbases shown in Figure 1, and these were separated, giving a hundred samples for the decade. These samples were analysed by pyrolysis gas chromatography and mass spectrometry to identify the dark pigment (Challinor 1989, 1995). They were also analysed for zinc, calcium, magnesium, manganese and copper. …
Australian Bushfire Management: a case study in wisdom versus folly
Roger Underwood. 2009. Australian Bushfire Management: a case study in wisdom versus folly
Roger Underwood is a renowned Australian forester with fifty years experience in bushfire management and bushfire science. He has worked as a firefighter, a district and regional manager, a research manager and senior government administrator. He is Chairman of The Bushfire Front, an independent professional group promoting best practice in bushfire management.
One man’s wisdom is another’s folly - Ralph Waldo Emerson
Many years ago, still a young man, I watched for the first time the grainy, flickering black and white film of the British infantry making their attack on the opening day of the Battle of the Somme. The stark and terrible footage shows the disciplined soldiers climbing from their trenches and, in line abreast, walking slowly across no-man’s land towards the enemy lines. They scarcely travel a few paces before the German machine gunners open up. They are mown down in their thousands. They are chaff before a wind of fire.
I can still remember being struck nerveless by these images, and later my anger when I realised what that calamitous carnage represented. It spoke of the deep incompetence of the Generals who devised this strategy of doom and then insisted upon its implementation. It spoke of front-line men led by people without front-line experience. It spoke of battle planners unable to think through the consequences of their plans, and who devalued human lives. It spoke of a devastating failure of the human imagination.
Worst of all, the strategies of the World War I Generals demonstrated that they had not studied, or that they had forgotten, the lessons of history. In the final year of the American Civil war, 50 years earlier, the Union army had been equipped for the first time with Springfield repeating rifles, replacing the single shot muskets they had previously used and still were being used by the Confederate army. The impact on Confederate soldiers attacking defenders armed with repeating rifles was identical to that later inflicted by machine guns on the Western Front. But it was a lesson unlearnt, of collective wisdom unregarded.
None of you will have any difficulty in seeing where this analogy is taking me.
The catastrophic bushfires in Victoria this year, and the other great fires of recent years in Victoria, New South Wales, the ACT and South Australia are dramatic expressions not just of killing forces unleashed, but of human folly. No less than the foolish strategies of the World War I Generals, these bushfires and their outcomes speak of incompetent leadership and of failed imaginations. Most unforgivable of all, they demonstrate the inability of people in powerful and influential positions to profit from the lessons of history and to heed the wisdom of experience.
Effect of low-temperature pyrolysis conditions on biochar for agricultural use
J. W. Gaskin, C. Steiner, K. Harris, K. C. Das, B. Bibens. 2008. Effect of low-temperature pyrolysis conditions on biochar for agricultural use. Transactions of the American Society of Agricultural and Biological Engineers, Vol. 51(6): 2061-2069.
Full text [here]
Selected excerpts:
Abstract:
The removal of crop residues for bio-energy production reduces the formation of soil organic carbon (SOC) and therefore can have negative impacts on soil fertility. Pyrolysis (thermoconversion of biomass under anaerobic conditions) generates liquid or gaseous fuels and a char (biochar) recalcitrant against decomposition. Biochar can be used to increase SOC and cycle nutrients back into agricultural fields. In this case, crop residues can be used as a potential energy source as well as to sequester carbon (C) and improve soil quality. To evaluate the agronomic potential of biochar, we analyzed biochar produced from poultry litter, peanut hulls, and pine chips produced at 400°C and 500°C with or without steam activation.
The C content of the biochar ranged from 40% in the poultry litter (PL) biochar to 78% in the pine chip (PC) biochar. The total and Mehlich I extractable nutrient concentrations in the biochar were strongly influenced by feedstock. Feedstock nutrients (P, K, Ca, Mg) were concentrated in the biochar and were significantly higher in the biochars produced at 500°C. A large proportion of N was conserved in the biochar, ranging from 27.4% in the PL biochar to 89.6% in the PC biochar. The amount of N conserved was inversely proportional to the feedstock N concentration. The cation exchange capacity was significantly higher in biochar produced at lower temperature. The results indicate that, depending on feedstock, some biochars have potential to serve as nutrient sources as well as sequester C.
Introduction:
… There are several lines of evidence that charcoal plays an important role in soil fertility. Charcoal has been identified as an important soil constituent in fertile Chernozems (Schmitdt et al., 1999) and in anthropogenic enriched dark soil (Terra Preta) found throughout the lowland portion of the Amazon Basin (Glaser et al., 2000). Research on tropical soils indicates that charcoal amendments can increase and sustain soil fertility (Steiner et al., 2007). The beneficial effects appear to be related to alterations in soil physical, chemical, and biological properties, such as reduced acidity (Topoliantz et al., 2005), increased cation exchange capacity (CEC) (Cheng et al., 2008; Liang et al., 2006), enhanced nitrogen (N) retention (Lehmann et al., 2003; Steiner et al., 2008b), increased microbiological activity (Steiner et al., 2008a), and increased mycorrhizal associations (Warnock et al., 2007). …
Charcoals produced from wildfire or traditional charcoal production may have different chemical and physical characteristics from pyrolytic biochars created under specific conditions for energy production. …
After forest fires, on average, only 3% of the N in the biomass is found in ash, which contains black carbon or biochar (Giardina et al., 2000). …
Studies of wildfire effects on biomass composition indicate that N begins to volatilize at 200°C, and above 500°C half of the N in organic matter is lost to the atmosphere. …
Conclusions:
Pyrolytic biochar has the potential to be used in agricultural production to sequester carbon and serve as a fertilizer. Although pyrolysis conditions are known to affect the chemical and physical characteristics of biochar, at the relatively low pyrolysis temperatures used in this study, feedstock characteristics had the greatest influence on key agricultural characteristics. Carbon concentrations in the biochars decreased with increasing mineral content of the feedstock. Little DC was leachable from the fresh biochar. A high proportion of the feedstock N was conserved in the biochar; however, the N may not be plant available. Nutrients such as P, K, and Ca are extractable with a weak double acid extractant and may be plant available.
The higher pyrolysis temperature increased nutrient concentrations, except for N, but decreased CEC. Recent literature has shown that natural long-term oxidation of biochar in the soil increases the amount of negative charges on the biochar surface (Cheng et al., 2008). Development and optimization of pyrolysis and post-production treatments to increase CEC or available nutrients is important in order to increase the immediate benefits of biochar applications in agriculture.
Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal
Christoph Steiner, Bruno Glaser, Wenceslau Geraldes Teixeira, Johannes Lehmann, Winfried E.H. Blum, and Wolfgang Zech. 2008. Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal. J. Plant Nutr. Soil Sci. 2008.
Full text [here]
Selected excerpts:
Abstract:
Leaching losses of N are a major limitation of crop production on permeable soils and under heavy rainfalls as in the humid tropics. We established a field trial in the central Amazon (near Manaus, Brazil) in order to study the influence of charcoal and compost on the retention of N. Fifteen months after organic-matter admixing (0–0.1 m soil depth), we added 15N-labeled (NH4)2SO4 (27.5 kg N ha–1 at 10 atom% excess). The tracer was measured in top soil (0–0.1 m) and plant samples taken at two successive sorghum (Sorghum bicolor L. Moench) harvests.
The N recovery in biomass was significantly higher when the soil contained compost (14.7% of applied N) in comparison to only mineral-fertilized plots (5.7%) due to significantly higher crop production during the first growth period. After the second harvest, the retention in soil was significantly higher in the charcoal-amended plots (15.6%) in comparison to only mineral-fertilized plots (9.7%) due to higher retention in soil. The total N recovery in soil, crop residues, and grains was significantly (p < 0.05) higher on compost (16.5%), charcoal (18.1%), and charcoal-plus-compost treatments (17.4%) in comparison to only mineral-fertilized plots (10.9%). Organic amendments increased the retention of applied fertilizer N. One process in this retention was found to be the recycling of N taken up by the crop. The relevance of immobilization, reduced N leaching, and gaseous losses as well as other potential processes for increasing N retention should be unraveled in future studies.
Introduction:
The fertility of highly weathered Ferralsols in the tropics is low, and soil organic matter (SOM) plays a major role in sustaining soil productivity. Thus, long-term intensive use is not sustainable without nutrient inputs where SOM stocks are depleted (Tiessen et al., 1994). Due to low nutrient-retention capacity and high permeability of these soils, strong tropical rainfalls cause rapid leaching of mobile nutrients such as those applied with mineral N fertilizers (Hölscher et al., 1997a; Giardina et al., 2000; Renck and Lehmann, 2004). …
Only relatively small amounts of charcoal are produced by the traditional slash-and-burn technique. Charcoal represents only 1.7% of the preburn biomass if a forest is converted into cattle pasture (Fearnside et al., 2001). Producing charcoal for soil amelioration from aboveground biomass instead of converting it to CO2 through burning might be an alternative to slash-and-burn (Lehmann et al., 2002; Steiner et al., 2004b; Lehmann et al., 2006).
The existence of so-called “Terra Preta de Índio” (Indian black earth) suggests that a human-induced accumulation of SOM can be maintained over centuries (Sombroek et al., 1993). These soils are exceptionally fertile, and their productivity is most likely linked to an anthropogenic accumulation of P and Ca associated with bone apatite (Lima et al., 2002) and black C (BC) as charcoal (Glaser et al., 2001).
Soil respiration in Amazonian plantations treated with charcoal, and mineral or organic fertilisers
Christoph Steiner, Murilo Rodrigues de Arruda, Wenceslau G. Teixeira, and Wolfgang Zech. 2008. Soil respiration curves as soil fertility indicators in perennial central Amazonian plantations treated with charcoal, and mineral or organic fertilisers. Trop. Sci. (2008)
Full text [here]
Selected excerpts:
Abstract:
We assessed substrate-induced respiration and soil chemical properties in order to study the influence of charcoal, nitrogen and phosphorus fertilisation on two different perennial crops in a confounded factorial design on a highly weathered Amazonian upland soil. Each plantation tested three different factors in three different levels making up 27 treatment combinations. Whereas the banana plantation received mineral fertilisation in addition to charcoal applications (3rd factor), the guarana (Paullinia cupana) plantation was fertilised organically using chicken manure and bone meal as the corresponding factors.
Charcoal increased pH, total nitrogen, availability of sodium, zinc, manganese, copper and soil humidity, and decreased aluminium availability and acidity in the mineral-fertilised plantation only. This caused a signifi cant increase in basal respiration and microbial efficiency in terms of carbon dioxide release per microbial carbon in the soil. The microbial biomass, efficiency and population growth after substrate addition was significantly increased with increasing levels of organic fertiliser amendments. We conclude that charcoal is a valuable component especially in inorganic-fertilised agricultural systems.
Introduction:
Without continuous fertilisation, the extremely nutrient-poor Amazonian upland soils show no potential for agriculture beyond a tree-year lifespan of the forest litter mat, once biological nutrient cycles are interrupted by slash-and-burn (Tiessen et al. 1994). Slash-and-burn agriculture is a common practice in the tropics (Giardina et al. 2000; Goldammer 1993) and is considered to be sustainable if adequate (up to 20 years) fallow periods follow a short period of cultivation (Kleinman et al. 1995). Fertilisation is necessary for continuous cropping, but the strongly weathered soils of the tropics have a low nutrient-retention capacity and the intense tropical rains wash easily available and mobile nutrients rapidly into deep soil layers unavailable to most crop plants (Giardina et al. 2000; Hölscher et al. 1997; Renck and Lehmann 2004). …
The widespread existence of an anthropogenic fertile dark soil in the Amazon proves that human soil-manipulation can create permanently fertile soil (Woods and McCann 1999). The Amazonian dark earths (or ‘Terra Preta de Índio’) are found at pre-Columbian settlements throughout Amazonia in patches ranging in size from less than a hectare to many square kilometres (McCann et al. 2001). Today, and as assumed in the past, those soils are and were intensively cultivated by the native population. Their fertility is most likely to be linked to an anthropogenic accumulation of P and calcium (Ca) from bones (Lima et al. 2002), depositions of these and many other nutrients from a variety of human habitation activities (Woods 2003), and black carbon (C) as charcoal (Glaser et al. 2001b; Lima et al. 2002). Amazonian dark earths contain significantly more C, N, Ca and potassium (K) and up to 13.9 g kg-1 phosphorus (P2O Pentoxide 5) (almost 4 g kg-1 available P) (Lima et al. 2002), and cation exchange capacity, pH value and base saturation are signifi cantly higher than in the surrounding Oxisols (Glaser et al. 2000; Zech et al. 1990). Charcoal persists in the environment over centuries and is responsible for the stability of the Amazonian dark earth’s SOM (Glaser et al. 2001a).
