Climate Change 1995 is a scientific assessment that was generated by more than 1 000 contributors from over 50 nations. It was jointly co-ordinated through two international agencies; the World Meteorological Organization and the United Nations Environment Programme. The assessment was completed by the Intergovernmental Panel on Climate Change (IPCC) with a primary aim of reviewing the current state of knowledge concerning the impacts of climate change on physical and ecological systems, human health, and socioeconomic factors. The second aim was to review the available information on the technical and economic feasibility of the potential mitigation and adaptation strategies.

Climate Change 1995

https://dspace.library.uu.nl/bitstream/handle/1874/25546/laanbroek_04_nitrogenasaregulatoryfactor.pdf;sequence=1

Nitrogen as a regulatory factor of methane oxidation in soils and sediments.

https://www.ars.usda.gov/ARSUserFiles/41695/Reprints/Scheutz_2009_409-455..pdf

Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions.

Human interaction with fire and vegetation occurs at many levels of human population density and cultural development, from subsistence cultures to highly technological societies. The dynamics of these interactions with respect to wildland fire are often difficult to understand and identify at short temporal scales. Dendrochronological fire histories from the Missouri Ozarks, coupled with human population data, offer a quantitative means of examining historic (1680-1990) changes in the anthropogenic fire regime. A temporal analysis of fire scar dates over the last 3 centuriqs indicates that the percent of sites burned and fire intervals of anthropogenic fires are conditioned by the following four limiting factors: (a) anthropogenic ignition, (b) surface fuel production, (c) fuel fragmentation, and (d) cultural behavior. During an ignition-dependent stage (fewer than 0.64 humans/km2), the percent of sites burned is logarithmically related to human population (r2 = 0.67). During a fuel-limited stage, where population density exceeds a threshold of 0.64 humans/km2, the percent of sites burned is independent of population increases and is limited by fuel production. During a fuel-fragmentation stage, regional trade allows population densities to increase above 3.4 humans/km2, and the percent of sites burned becomes inversely related to population (r2 = 0.18) as decreases in fuel continuity limit the propagation of surface fires. During a culture-dependent stage, increases in the value of timber over forage greatly reduce the mean fire interval and the percent of sites burned. Examples of the dynamics of these four stages are presented from the Current River watershed of the Missouri Ozarks.

https://www.nrs.fs.fed.us/pubs/jrnl/2002/nc_2002_Guyette_001.pdf

Dynamics of an Anthropogenic Fire Regime

SUMMARY The root and butt rot caused by Heterobasidon annosum is one of the most destructive diseases of conifers in the northern temperate regions of the world, particularly in Europe Economic losses attributable to Heterobasidion infection in Europe are estimated at 800 million euros annually The fungus has been classified into three separate European intersterile species P ( H annosum ), S ( H parviporum ) and F ( H abietinum ) based on their main host preferences: pine, spruce and fir, respectively In North America, two intersterile groups are present, P and S/F, but these have not been given scientific names The ecology of the disease spread has been intensively studied but the genetics, biochemistry and molecular aspects of pathogen virulence have been relatively little examined Recent advances in transcript profiling, molecular characterization of pathogenicity factors and establishment of DNA-transformation systems have paved the way for future advances in our understanding of this pathosystem Taxonomy: Heterobasidion annosum (Fr) Bref, H parviporum Niemela & Korhonen and H abietinum Niemela & Korhonen; kingdom Fungi; class Basidiomycotina; order Aphyllophorales; family Bondarzewiaceae; genus Heterobasidion  Identification: presence of the fungus fruit bodies, basidiocarps whitish in the margins, upper surface is tan to dark brown, usually irregular shaped, 35 ( − 7) cm thick and up to 40 cm in diameter; pores 5‐19, 7‐22 and 13‐26 mm 2 for the P, F and S groups, respectively Small brownish non-sporulating postules develop on the outside of infected roots Asexual spores (conidiospores) are 38‐66 × 28‐50 µ m in size Mating tests are necessary for identification of intersterility groups Host range: The fungus attacks many coniferous tree species In Europe, particularly trees of the genera Pinus and Juniperus (P), Picea (S), Abies (F) and in North America Pinus (P) and Picea , Tsuga and Abies (S/F) To a lesser extent it causes root rot on some decidous trees ( Betula and Quercus ) Disease symptoms: symptoms (eg exhudation of resin, crown deterioration) due to Heterobasidion root rot in living trees are not particularly characteristic and in most cases cannot be distinguished from those caused by other root pathogens Heterobasidion annosum sl is a white rot fungus Initial growth in wood causes a stain that varies in colour depending on host tree species Incipient decay is normally pale yellow and it develops into a light brown decay to become a white pocket rot with black flecks in its advanced stage Control: silvicultural methods (eg stump removal), chemicals (urea, borates) and biological control agent ( Phlebiopsis gigantea , marketed as PG Suspension® in the UK, PG IBL® in Poland and Rotstop® in Fennoscandia) are commonly used approaches for minimizing the disease spread

https://pub.epsilon.slu.se/1365/2/Adomasfin1.pdf

Conifer root and butt rot caused by Heterobasidion annosum (Fr.) Bref. s.l.

Nitrogen losses and soil water acidity after clear-felling of fertilized experimental plots in a Pinus sylvestris stand

There is increasing commercial interest in treating stumps to restrict the spread of root rot [Heterobasidion annosum (Fr.) Bref.] when thinning Swedish coniferous forests during the summer. Both chemical and biological substances are used for this purpose. During the treatment, however, a large proportion of the substance applied is spilled beside the stumps. A field study was conducted on the effects of stump-treatment substances on various ground-vegetation species in a Picea abies (L.) Karst. forest in Sweden. Three different substances commonly used in forestry were studied: urea solution (0.23 kg N m-2), borate solution (10 g B m-2) and a fungal preparation of Phlebiopsis gigantea (Fr.) Jul. spores (1 g spores m-2). The principal objectives were to assess whether any of the substances were harmful to plants and whether plant species differed in their sensitivity. Both borate and urea solution caused severe damage to most ground-vegetation species tested. Bryophytes were affected more strongly than v...

Effects of stump-treatment substances for root-rot control on ground vegetation and soil properties in a Picea abies forest in Sweden.

SW Sweden has very acidic forest soils because of deposition ofair-borne pollutants. Large-scale liming and fertilization have been proposed as countermeasures against a possible future development of forest decline. To test the effects of suggested treatments, liming (3 or 6 t ha1) and fertilization with easily soluble PK (25 or 50 kg P, 80 or 160 kg K ha1) or N(20 kg N ha1 annually in the form of NH4 NO3) were applied in different combinations in four experiments in 30–60 yr-old Picea abies forests in SW Sweden. Four yearsafter the initial application of the fertilizers, samples were taken from the O-horizon and the two uppermost 5 cm thick layersof the mineral soil. Their pH(H2O) and easily extractable Ca, Mg, K, P and inorganic N contents were analyzed. Samples werealso incubated to estimate net N mineralization and potential nitrification rates. Liming increased the pH by 0.6–1 unit in the O-horizon, and by 0.1 unit in the mineral soil. The Ca + Mg content increased by 15–25 kmolc ha1 (4–8 foldincrease) in the O-horizon of the limed plots, while an increaseof 5 kmolc ha1 (two-fold increase) was observed in theuppermost 5 cm of the mineral soil. Liming did not affect extractable P, K or inorganic N contents. Net N mineralization and potential nitrification rates in the O-horizon were enhanced 1.5- and 6-fold, respectively, by liming, but it had no apparenteffect in the mineral soil. N fertilization caused a slight increase (1.5 kg ha1) in the content of inorganic N, buthad no effects on the other variables measured. The amount ofextractable P was raised by 16 kg ha1 in plots given the high P dose (50 kg ha1), but no other effects of PK fertilization were detected.

Effects of liming and fertilization (N,PK) on chemistry and nitrogen turnover in acidic forest soils in SW Sweden

Previous analyses of soil water beneath mounds resulting from scarification have implied that this forestry measure increases leaching of inorganic N. However, more recent soil-water studies have not confirmed this assumption. The soil study presented here examined the pools of inorganic N in different microsites emanating from a simulated disc trenching, i. e. the mound with underlying soil, the furrow bottom and the undisturbed soil. The study was made five years after scarification. The mound itself with underlying soil had a larger pool of inorganic N than the undisturbed soil. This was mainly because of an increase in the embedded humus layer, thus implying a larger net N mineralisation and/or lower losses. However, when pools of inorganic N per hectare were calculated, taking into consideration that a scarified area comprises 25% mounds, 25% furrows and 50% undisturbed soil, there was no increase in pools of inorganic N when compared with an area not subjected to scarification. This observation supports the finding of the more recent soil-water studies mentioned, i. e., that leaching seems not to be influenced by soil scarification. The scarification was made as a split-plot treatment on main-plots in an old experiment with different N doses. Thus, the effect of the previous N fertilisation could also be evaluated. Two N doses were tested beside the unfertilised control: 720N (3 × 240 kg N ha–1 yr–1) and 1800N (3 × 600 kg N ha–1 yr–1). The last fertiliser application was made six years before the clearcutting and 13 years before the soil sampling. The previously fertilised main-plots had larger pools of inorganic N than the control plots.

Hans-Örjan Nohrstedt

Papers

Nitrogen losses and soil water acidity after clear-felling of fertilized experimental plots in a Pinus sylvestris stand

Effects of stump-treatment substances for root-rot control on ground vegetation and soil properties in a Picea abies forest in Sweden.

Effects of liming and fertilization (N,PK) on chemistry and nitrogen turnover in acidic forest soils in SW Sweden

Effects of soil scarification and previous N fertilisation on pools of inorganic N in soil after clear-felling of a Pinus sylvestris (L.) stand.

Effect of liming and N-fertilization on denitrification and N2-fixation in an acid coniferous forest floor