Taxonomy and phylogeny of the novel rhytidhysteron-like collections in the Greater Mekong Subregion

During our survey into the diversity of woody litter fungi across the Greater Mekong Subregion, three rhytidhysteron-like taxa were collected from dead woody twigs in China and Thailand. These were further investigated based on morphological observations and multi-gene phylogenetic analyses of a combined DNA data matrix containing SSU, LSU, ITS, and tef1-α sequence data. A new species of Rhytidhysteron, R. xiaokongense sp. nov. is introduced with its asexual morph, and it is characterized by semi-immersed, subglobose to ampulliform conidiomata, dark brown, oblong to ellipsoidal, 1-septate, conidia, which are granular in appearance when mature. In addition to the new species, two new records from Thailand are reported viz. Rhytidhysteron tectonae on woody litter of Betula sp. (Betulaceae) and Fabaceae sp. and Rhytidhysteron neorufulum on woody litter of Tectona grandis (Lamiaceae). Morphological descriptions, illustrations, taxonomic notes and phylogenetic analyses are provided for all entries.

Novel saprobic Hermatomyces species (Hermatomycetaceae, Pleosporales) from China (Yunnan Province) and Thailand

During our survey of the diversity of woody litter fungi in China and Thailand, three Hermatomyces species were collected from dead woody twigs of Dipterocarpus sp. (Dipterocarpaceae) and Ehretia acuminata (Boraginaceae). Both morphology and multigene analyses revealed two taxa as new species (Hermatomyces turbinatus and H. jinghaensis) and the remaining collections as new records of H. sphaericus. Hermatomyces turbinatus is characterized by 1) dimorphic conidia, having circular to oval lenticular conidia and 2) turbinate conidia consisting of two columns with two septa composed of 2–3 cells in each column. Hermatomyces jinghaensis is characterized by dimorphic conidia, having circular to oval lenticular conidia and clavate or subcylindrical to cylindrical conidia and consisting of one or two columns with 6–8 cells in each column. Phylogenetic analyses of combined LSU, ITS, tub2, tef1-α and rpb2 sequence data supports the placement of these new taxa within Hermatomycetaceae with high statistical support.

Non-Destructive Fuel Volume Measurements Can Estimate Fine-Scale Biomass across Surface Fuel Types in a Frequently Burned Ecosystem

Measuring wildland fuels is at the core of fire science, but many established field methods are not useful for ecosystems characterized by complex surface vegetation. A recently developed sub-meter 3D method applied to southeastern U.S. longleaf pine (Pinus palustris) communities captures critical heterogeneity, but similar to any destructive sampling measurement, it relies on separate plots for calculating loading and consumption. In this study, we investigated how bulk density differed by 10-cm height increments among three dominant fuel types, tested predictions of consumption based on fuel type, height, and volume, and compared this with other field measurements. The bulk density changed with height for the herbaceous and woody litter fuels (p < 0.001), but live woody litter was consistent across heights (p > 0.05). Our models predicted mass well based on volume and height for herbaceous (RSE = 0.00911) and woody litter (RSE = 0.0123), while only volume was used for live woody (R2 = 0.44). These were used to estimate consumption based on our volume-mass predictions, linked pre- and post-fire plots by fuel type, and showed similar results for herbaceous and woody litter when compared to paired plots. This study illustrates an important non-destructive alternative to calculating mass and estimating fuel consumption across vertical volume distributions at fine scales.

Secondary disturbance following a deposit of volcanic tephra: A 30 year record from old-growth forest understory

Forest disturbance is usually described by effects on trees, and small disturbances to forest understory are seldom studied. Nevertheless, effective analyses of succession need to consider both stand-replacing and subsequent “secondary” disturbances in both canopy and understory. We estimated characteristics of 13 types of secondary disturbance in old-growth forest understory, and of canopy cover, after the 1980 tephra (aerially transported volcanic ejecta) deposition from Mount St. Helens, Washington. We sampled 100 1-m2 plots at each of four sites for vegetation change and types of disturbance at ten times from 1980-2010; we sampled tree canopy above each plot in 1980 and 2016. The number of canopy gaps increased 23 % and mean gap dimension 68 % during 36 years, mostly from loss of Abies amabilis. Secondary disturbance in understory affected 1.4 % of stand area per year. The areas affected by soil disturbance and effects of woody litter were similar. Erosion, greater in deep than in shallow tephra, peaked in 1981, whereas most litter-caused disturbances increased after 2000. Less frequent litter-based disturbances covered greater area. Our results differ from conclusions about non-volcanic understory disturbances. Secondary disturbances are variable, need more study, and are likely to affect many other systems.

Long-term litter type treatments alter soil carbon composition but not microbial carbon utilization in a mixed pine-oak forest

Changes in litter and nutrient inputs into soil could have significant consequences on forest carbon (C) dynamics via controls on the structure and microbial utilization of soil organic C (SOC). In this study, we assessed changes in physical fractions (250–2000 μm, 53–250 μm, and < 53 μm soil aggregates) and chemical fractions (labile, intermediate and recalcitrant pools) of SOC in the top 20 cm mineral soil layer and their influences on microbial substrate utilization after eight years of experiment in a mixed pine-oak forest. The litter treatments included: control (Lcon), litter removal (Lnil), fine woody litter addition (Lwoody), leaf litter addition (Lleaf) and a mix of leaf and fine woody litter (Lmix). Nitrogen (N) addition (application rates of 0, 5 and 10 g N m−2 year−1, respectively) was also applied. We found that complete removal of forest-floor litter (Lnil) significantly reduced the pool sizes of all SOC fractions in both the physical and chemical fractions compared with treatments that retained either leaf litter (Lleaf) or mixture of leaves and fine woody materials (Lmix). The type of litter was more important in affecting SOC fractions than the quantity of inputs; neither the level of N addition rate nor its interaction with litter treatment had significant effects on both physical and chemical SOC fractions. Microbial respiration differed significantly among the treatments of varying litter types. However, the effectiveness of microbial C utilization inferred by microbial C use efficiency and biomass-specific respiration was not affected by either the litter treatments or N addition. These results suggest that despite significant changes in SOC composition due to long-term treatments of forest-floor litter and N addition in this mixed pine-oak forest of temperate climate, microbial C utilization strategies remain unaffected.

Bridging mapping and simulation modelling in the ecosystem service assessments of boreal forests: effects of bioenergy production on carbon dynamics

Background Increasing the use of forest harvest residues for bioenergy production reduces greenhouse emissions from the use of fossil fuels. However, it may also reduce carbon stocks and habitats for deadwood dependent species. Consequently, simple tools for assessing the trade-offs of alternative management practices on forest dynamics and their services to people are needed. The objectives of this study were to combine mapping and simulation modelling to investigate the effects of forest management on ecosystem services related to carbon cycle in the case of bioenergy production; and to evaluate the suitability of this approach for assessing ecosystem services at the landscape level. Stand level simulations of forest growth and carbon budget were combined with extensive multi-source forest inventory data across a southern boreal landscape in Finland. Stochastic changes in the stand age class distribution over the study region were simulated to mimic variation in management regimes. Results The mapping framework produced reasonable estimates of the effects of forest management on a set of key ecosystem service indicators: the annual carbon stocks and fluxes of forest biomass and soil, timber and energy-wood production and the coarse woody litter production over a simulation period 2012–2100. Regular harvesting, affecting the stand age class distribution, was a key driver of the carbon stock changes at a landscape level. Extracting forest harvest residues in the final felling caused carbon loss from litter and soil, particularly with combined aboveground residue and stump harvesting. It also reduced the annual coarse woody litter production, demonstrating negative impacts on deadwood abundance and, consequently, forest biodiversity. Conclusions The refined mapping framework was suitable for assessing ecosystem services at the landscape level. The procedure contributes to bridging the gap between ecosystem service mapping and detailed simulation modelling in boreal forests. It allows for visualizing ecosystem services as fine resolution maps to support sustainable land use planning. In the future, more detailed models and a wider variety of ecosystem service indicators could be added to develop the method.

Loculosulcatispora thailandica gen. et sp. nov. (Sulcatisporaceae), saprobic on woody litter in Thailand

A new monotypic coelomycetous genus, Loculosulcatispora (type species L. thailandica) is introduced in Pleosporales from woody litter in Thailand. Phylogenetic analysis of combined non-translated loci (SSU, LSU, ITS) and protein-coding regions (tef1-α, rpb2) shows the genus is a distinct lineage in Sulcatisporaceae. Loculosulcatispora is distinguished from other genera in the family, by having 1-celled, oblong, hyaline, smooth-walled conidia with guttules. Comprehensive morphological descriptions and illustrations are provided for the new genus and species.

Land-use change and climate change mitigation potential of agricultural soils in Finland

&lt;p&gt;We aimed to estimate a nation-wide potential to improve the carbon balance of the land use sector by removing part of the current croplands on mineral soil from food and feed production to extensive grasslands or afforestation in Finland. &amp;#160;We combined the existing data on forest and agricultural production, and climate with predictive capacity of YASSO07 soil carbon model to estimate changes of soil carbon stock (SOC) in Finland over the past land use change (LUC) from forest to agriculture in comparison with alternative LUC or continuous agriculture in future.&lt;/p&gt;&lt;p&gt;The model analysis revealed that SOC loss after deforestation during the cultivation period originated mainly from the absence of woody litter input. The non-woody litter input of the forest was comparable to that of the agricultural residues thus the SOC originating from non-woody litter has not changed much during cultivation. The model estimated approximately a 30 year delay in positive soil carbon balance after the afforestation. Longer for Norway spruce than for the Pubescent birch. The comparison of two dominant tree species used for afforestation highlighted a difference in soil versus biomass carbon sequestration. The total forest biomass production and total carbon stock was larger for spruce stands than for birch stands. However, due to larger foliar and fineroot litter input birch stands sequestered more carbon into the soil than spruce stands. The analysis further revealed that extensification of cropland to grassland would not meet 4 per mill soil carbon sequestration criterion needed for achieving Paris climate CO2 reduction target and due to the spatial limitation of afforestation other management measures need to be considered e.g. adding biochar to soils for successful and more permanent CO2 offsetting.&lt;/p&gt;