Fires In Pine Forests Research Articles

Changes in the Microbiological and Physico-Chemical Properties of Soils after Fires in Pine and Birch Forests of Central Regions of the Zabaikal Krai

The microbiological and some physico-chemical properties of illuvial-ferruginous soddy-podburs (Entic Rustic Podzols) soils in Scots pine forests and gray-humic typical light loamy soils (Umbrisols) in secondary birch forests of the central regions of the Zabaikal krai have been studied. Fires in soddy-podburs pine forests resulted in decrease in the total exchangeable basis, total nitrogen, mobile forms of potassium and phosphorus, and in increase in the proportion of C : N; while in birch forests, on the contrary, an increase of the mentioned indicators and a narrowing of the C : N proportion in the gray-humic typical soils were observed. The content of humus in the upper soil horizon decreases only in recently burned Scots pine forests after a high-severity fire, while in other sites it increases. A decrease in the soil acidity was observed at all burned sites. High-severity fires lead to a significant decrease in the content of microbial biomass and the intensity of basal respiration, as well as to a change in the structure of ecological and trophic groups of microorganisms in the soils up to a depth of 10 cm of the mineral horizon, while low-severity fires mainly affect the duff. The qCO2 coefficient increased 2–5 times after fires in the duff and 1.5–2 times in the humus horizon only after high-severity fires. In recently burned Scots pine forests, the storage of microbial biomass and microbial production of carbon dioxide significantly decreased up to a depth of 10 cm of the mineral soil layer. In the steppe site formed after the impact of fires in the pine forest, and in the birch forest after a high-severity fire, in the humus horizon the carbon storage of microbial biomass decreased by 15–20%, and the microbial production of CO2 increased by 10–20%, predetermining the predominance of mineralization processes. The considered post-fire transformation of the structural and functional parameters of soil microbiocenosis, as well as a 20–40% decrease in the total carbon storage of microbial biomass in the soils of all sites demonstrate a long recovery period of soils after fires in light coniferous and deciduous forests of the central regions of the Zabaikal krai.

Evolution of vegetation of the Lake Khanka Depression in the southernmost of the Russian Far East in the Holocene

This paper presents recently obtained palynological results regarding to the evolution of vegetation of the Khanka Depression in the Holocene. Radiocarbon-dated pollen records evidence that the evolution of vegetation in this area was more complicated than one has previously thought. As a result of a rapid increase in heat supply in the Early Holocene, the plants of the Manchurian flora, primarily Ulmus davidiana, Ulmus laciniata, Quercus mongolica, and Pinus koraiensis, began to expand to the Khanka Depression. However, Sphagnum mires with Betula grandulosa, Betula pubescens, and sparse forests of Larix, still remained in plains and valleys. Picea jezoensis, Pinus pumila, Betula grandulosa, Betula alnobetula, Betula pubescens, Pinus pumila and Larix were widespread in the mountains. During the Middle Holocene these cold-tolerant plants of the north-boreal flora, completely disappeared. Broad-leaved and fir-pine forests have become widespread. The vegetation of the Khanka Depression compared with modern one was characterized by great diversity of broad-leaved plants. At the beginning of the Late Holocene cooling has caused the expansion of Betula grandulosa, Betula alnobetula, Abies nephrolepis, Picea jezoensis, Betula pubescens, Betula costata, and Alnus hirsuta. The areas of forb meadows expanded on the plains. Larch sparse forests, thickets with domination of Betula grandulosa and Sphagnum mires reappeared. However, some thermophilic plants, such as Pinus koraiensis, Abies nephrolepis, Quercus mongolica, Juglans mandshurica, Ulmus davidiana, and Ulmus laciniata have survived. Since 1 300 cal BP, vegetation of the Khanka Depression began to degrade due to fires, plowing of the land, and deforestation.

Gas-phase pyrolysis products emitted by prescribed fires in pine forests with a shrub understory in the southeastern United States

Abstract. In this study we identify pyrolysis gases from prescribed burns conducted in pine forests with a shrub understory captured using a manual extraction device. The device selectively sampled emissions ahead of the flame front, minimizing the collection of oxidized gases, with the captured gases analyzed in the laboratory using infrared (IR) absorption spectroscopy. Results show that emission ratios (ERs) relative to CO for ethene and acetylene were significantly greater than in previous fire studies, suggesting that the sample device was able to collect gases predominantly generated prior to ignition. Further evidence that ignition had not begun was corroborated by novel IR detections of several species, in particular naphthalene. With regards to oxygenated species, several aldehydes (acrolein, furaldehyde, acetaldehyde, formaldehyde) and carboxylic acids (formic, acetic) were all observed; results show that ERs for acetaldehyde were noticeably greater, while ERs for formaldehyde and acetic acid were lower compared to other studies. The acetylene-to-furan ratio also suggests that high-temperature pyrolysis was the dominant process generating the collected gases.

Глубина прогорания торфа и потери углерода при лесном подземном пожаре

Глубина прогорания торфа и потери углерода при лесном подземном пожаре

The nitrogen reserves in sandy podzols after controlled fires in pine forests of Central Siberia

The influence of ground fires of different intensities on the nitrogen pool in the sandy soils under pine forests of the middle taiga zone after their experimental burning was studied. The contents of total nitrogen and its ammonium form increased due to the input of great amounts of plant falloff during the first year after the fire. Within two years after the fire, the content of nitrogen and the percentages of its forms approached their initial values before the fire. The adverse effect of the pyrogenic factor on the biological activity of the sandy podzols was shown.

Development of current stand structure in dry fir-pine forests of eastern Washington

Stand reconstruction, using live trees and deadwood, provided a four to five hundred year recruitment history for the current stand structure in dry fir-pine forests of northern Washington, USA. The lengthy structural record indicated these dry fir-pine forests were resilient to change, that all forest conditions were transient, and that forests were currently transitioning away from maximum tree density levels. Historically, frequent fires maintained low tree abundance, but fire cycles lengthened in the 1860s as Euro-settlement progressed. Average stand density had already increased to 194% (SD = 116) of 1860 levels by the start of effective fire suppression in 1915. From the 1930s to 1960s, average stand density peaked at 258% (SD = 98) of 1860 levels. By 2000, tree mortality in these overstocked stands had reduced average stand densities to 68% (SD = 19) of maximum levels. However, tree densities in 2000 still averaged 173% (SD = 64) above historical levels. Although there had been significant tree recruitment and a century without fire, the trees present in the historic stands provided 75% (SD = 13) of the basal area in 2000. Numerous understory (< 7.6 cm dbh) trees (252 trees/ha, SD = 97) were present in 1860 stands and these trees contributed more basal area than the historic overstory in 2000. In the absence of fire and without human intervention, the sampled stands have decreased in overall tree density from maximum levels while representation of shade-tolerant species, range and evenness of age-class structure, and abundance of old forest (live tree and deadwood) legacies have increased.

Amphibians and Fire in Longleaf Pine Ecosystems: Response to Schurbon and Fauth

3%ofthisonce-widespreadecosystem remains (Ware et al. 1993). Longleaf pine sa-vannas are home to at least 35 amphibian, 46 reptile, 45bird, and 36 mammal species, many of which depend al-mostexclusivelyonlongleafpinesavannas(Means2004).Manyresearchershaveconcludedthattheseandotheran-imals benefit from maintenance of longleaf pine savannaby prescribed burning (Mushinsky 1985; Engstrom 1993;James et al. 1997). Because natural fires no longer sweepthrough remaining tracts of longleaf pine, land managersmust apply prescribed burns to simulate the rejuvenat-ing effects of fire (Brennan et al. 1998). In the past twodecades, the frequency of prescribed burns has been rec-ommended on ever shorter intervals to restore habitatfeatures eroded by decades of fire suppression (Engstromet al. 1984; Cox et al. 1987; Weigl et al. 1989; Engstrom1993; Tucker & Robinson 2003; Means 2004).Schurbon and Fauth (2003) suggest decreasing the fre-quency of prescribed burns from the current 2–3 years to3–7 years in order to “better maintain diverse amphibianand plant” assemblages in southern pine forests. Theirsuggestion was based on a 1-year study of amphibianssampled at 15 ponds within the Francis Marion NationalForest, South Carolina. We believe that their study designand sampling effort were inadequate and, therefore, thattheir conclusions may be invalid. For reasons elaboratedbelow, we discourage land managers from following theirrecommendationandsuggestthata1-to3-yearfire-returninterval be the goal for prescribed fire in pine forests ofthe southeastern U.S. coastal plain.

Microbial biomass and abundance after forest fire in pine forests in Japan

Microbial characteristics of soil are being evaluated increasingly as sensitive indicators of soil health because of the clear relationship between microbial diversity, soil and plant quality and ecosystem sustainability. This study aimed to determine microbial carbon biomass and microbial abundance after fire to estimate the degree of damage, including the rate of recovery of micro‐organisms, in each area. The study also aimed to establish relationships between microbial biomass and microbial abundance and the physico‐chemical properties of the soil. The study was conducted in three different study areas in Hiroshima prefecture, one unburned area and two burnt areas (one immediately after and one 2 years after fire). anova showed a significant difference in microbial carbon biomass and microbial abundance among the study areas. Microbial carbon biomass and microbial abundance were highest in the unburned area, followed by the area burnt 2 years ago and lastly by the area studied immediately after fire. Carbon biomass was highly correlated with microbial abundance (r2 = 0.950). Carbon biomass and microbial abundance were shown to be significantly correlated to the soil's physico‐chemical properties, such as pH, moisture content, water‐holding capacity and carbon : nitrogen (C : N) ratio. However, the C : N ratio was closely correlated to both carbon biomass and microbial abundance with r2 = 0.705 (P &lt; 0.01) and r2 = 0.560 (P &lt; 0.01), respectively.

Paleoecologic, paleoclimatic, and evolutionary significance of the Oligocene Creede flora, Colorado

Application of multivariate statistical techniques, especially correspondence analysis, results in the recognition of four major communities for the Creede plant assemblages: fir-spruce forest, fir-pine forest, pine-juniper forest or woodland, and mountain mahogany chaparral. Physiognomy of the Creede assemblages indicates a mean annual temperature of &lt;2.5°C. Paleoaltitudinal estimates based on this temperature estimate are inconsistent with physiographic and structural data of post-depositional uplift, unless the climatic effects of a closed basin are factored in; these effects imply that the Creede paleotemperature (and hence paleoaltitude) is applicable to the caldera rim. A variety of data indicate that summers were dry and most precipitation occurred as snow. The stratigraphic sequence of assemblages indicates that significant precipitational change occurred during deposition of the Creede plant-bearing beds.Chamaebatiaria, a shrub that now inhabits dry, open environments, had an ancestral taxon characteristic of the Creede fir-forest communities and strongly indicates a major shift in habitat for this lineage during the Neogene. A second genus,Luetkea, which is now herbaceous, is represented by a probable woody ancestral taxon that was common in the Creede forest communities. Consideration of the adaptive and morphologic histories of the Creede lineages suggests that physiologic adaptation may precede morphologic change. The Creede forest communities have no modern homologues.

Litter dynamics in two Sierran mixed conifer forests. I. Litterfall and decomposition rates

Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forests (giant sequoia–fir and fir–pine) in the southern Sierra Nevada of California. The giant sequoia–fir forest (GS site) was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. &amp; Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Litterfall, including large woody debris &lt;15.2 cm in diameter, at the GS site averaged 6364 kg•ha−1•year−1 compared with 4355 kg•ha−1•year−1 at the FP site. Compared with other temperate coniferous forests, annual variability in litterfall (as computed by the ratio of the annual maximum/minimum litterfall) was extremely high for the GS site (5.8:1) and moderately high for the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fir (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5–15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia–fir forest type may result in higher litter accumulation rates than in the fir–pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (&lt;15.2 cm diameter) decomposition yielded lower decay constants than did the litterbag study and therefore longer times to 95% decay (57 years for the GS site and 62 years for the FP site).

Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. &amp; Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p &lt; 0.05), lignin concentration (r2 = 0.92, p &lt; 0.05), and acid detergent fiber concentration (r2 = 0.80, p &lt; 0.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

The Use of Fires in Pine Forests

The Use of Fires in Pine Forests

The Use of Fires in Pine Forests

The Use of Fires in Pine Forests