Comparison of Archaeal Communities in Mineral Soils at a Boreal Forest in Finland and a Cold-Temperate Forest in Japan

AbstractThe boreal forest is among the largest terrestrial biomes on earth, storing more carbon (C) than the atmosphere. Due to rapid climatic warming and enhanced human development, the boreal region may have begun transitioning from a net C sink to a net source. This raises serious concern that old biogenic soil C can be re-introduced into the modern C cycle in near future. Combining bio-decay experiments, mixing models and the Keeling plot method, we discovered a distinct old pre-bomb organic carbon fraction with high biodegradation rate. In total, 34 ± 12% of water-extractable organic carbon (WEOC) in podzols, one of the dominating boreal soil types, consisted of aged (~ 1000 year) labile C. The omission of this aged (i.e., Δ14C depleted) WEOC fraction in earlier studies is due to the co-occurrence with Δ14C enriched modern C formed following 1950s nuclear bomb testing masking its existence. High lability of aged soil WEOC and masking effects of modern Δ14C enriched C suggests that the risk for mobilization and re-introduction of this ancient C pool into the modern C cycle has gone undetected. Our findings have important implications for earth systems models in terms of climate-carbon feedbacks and the future C balance of the boreal forest.

Download Full-text

Distinct Climate Effects on Dahurian Larch Growth at an Asian Temperate-Boreal Forest Ecotone and Nearby Boreal Sites

Forests ◽

10.3390/f13010027 ◽

2021 ◽

Vol 13 (1) ◽

pp. 27

Author(s):

Enzai Du ◽

Yang Tang

Keyword(s):

Climate Change ◽

Boreal Forest ◽

Temperate Forest ◽

Growing Season ◽

Maximum Temperature ◽

Dahurian Larch ◽

Growth Responses ◽

Significant Difference ◽

Growing Season Precipitation ◽

Forest Ecotone

Climate change is exerting profound impacts on the structure and function of global boreal forest. Compared with their northern counterparts, trees growing at the southern boreal forest and the temperate-boreal forest ecotone likely show distinct responses to climate change. Based on annual basal areal increment (BAI) of Dahurian larch (Larix gmelinii Rupr.) plantations with similar ages, tree densities and soil nutrient conditions, we investigated the tree growth responses to inter-annual climate variations at an Asian temperate-boreal forest ecotone and nearby boreal sites in northeast China. Annual BAI changed nonlinearly with cambial age in the form of a lognormal curve. The maximum annual BAI showed no significant difference between the two bioregions, while annual BAI peaked at an elder age at the boreal-temperate forest ecotone. After eliminating the age associated trend, conditional regression analyses indicate that residual BAI at the boreal sites increased significantly with higher growing-season mean nighttime minimum temperature and non-growing-season precipitation, but decreased significantly with higher growing-season mean daytime maximum temperature during the past three decades (1985–2015). In contrast, residual BAI at the boreal-temperate forest ecotone only showed a positive and weak response to inter-annual variations of growing-season precipitation. These findings suggest distinct effects of inter-annual climate variation on the growth of boreal trees at the temperate-boreal forest ecotone in comparison to the southern boreal regions, and highlight future efforts to elucidate the key factors that regulate the growth ofthe southernmost boreal trees.

Download Full-text

The priming effect of soluble carbon inputs in organic and mineral soils from a temperate forest

Oecologia ◽

10.1007/s00442-015-3290-x ◽

2015 ◽

Vol 178 (4) ◽

pp. 1239-1250 ◽

Cited By ~ 26

Author(s):

Hui Wang ◽

Wenhua Xu ◽

Guoqing Hu ◽

Weiwei Dai ◽

Ping Jiang ◽

...

Keyword(s):

Temperate Forest ◽

Priming Effect ◽

Mineral Soils ◽

Soluble Carbon

Download Full-text

Monitoring of forest changes using unsupervised methods: A case study from boreal forest on mineral soils

Scandinavian Journal of Forest Research ◽

10.1080/02827589709355424 ◽

1997 ◽

Vol 12 (4) ◽

pp. 362-369 ◽

Cited By ~ 5

Author(s):

Jari Varjo ◽

Sten Folving

Keyword(s):

Boreal Forest ◽

Unsupervised Methods ◽

Mineral Soils

Download Full-text

Archaeal Communities in Boreal Forest Tree Rhizospheres Respond to Changing Soil Temperatures

Microbial Ecology ◽

10.1007/s00248-011-9837-4 ◽

2011 ◽

Vol 62 (1) ◽

pp. 205-217 ◽

Cited By ~ 19

Author(s):

Malin Bomberg ◽

Uwe Münster ◽

Jukka Pumpanen ◽

Hannu Ilvesniemi ◽

Jussi Heinonsalo

Keyword(s):

Boreal Forest ◽

Forest Tree ◽

Soil Temperatures ◽

Archaeal Communities

Download Full-text

Seven Ways a Warming Climate Can Kill the Southern Boreal Forest

Forests ◽

10.3390/f12050560 ◽

2021 ◽

Vol 12 (5) ◽

pp. 560

Author(s):

Lee E. Frelich ◽

Rebecca A. Montgomery ◽

Peter B. Reich

Keyword(s):

Boreal Forest ◽

Boreal Forests ◽

Temperate Forest ◽

Sudden Change ◽

Wildlife Habitat ◽

Gradual Change ◽

Temperate Trees ◽

Coniferous Boreal Forest ◽

Understory Trees ◽

Overstory Trees

The southern boreal forests of North America are susceptible to large changes in composition as temperate forests or grasslands may replace them as the climate warms. A number of mechanisms for this have been shown to occur in recent years: (1) Gradual replacement of boreal trees by temperate trees through gap dynamics; (2) Sudden replacement of boreal overstory trees after gradual understory invasion by temperate tree species; (3) Trophic cascades causing delayed invasion by temperate species, followed by moderately sudden change from boreal to temperate forest; (4) Wind and/or hail storms removing large swaths of boreal forest and suddenly releasing temperate understory trees; (4) Compound disturbances: wind and fire combination; (5) Long, warm summers and increased drought stress; (6) Insect infestation due to lack of extreme winter cold; (7) Phenological disturbance, due to early springs, that has the potential to kill enormous swaths of coniferous boreal forest within a few years. Although most models project gradual change from boreal forest to temperate forest or savanna, most of these mechanisms have the capability to transform large swaths (size range tens to millions of square kilometers) of boreal forest to other vegetation types during the 21st century. Therefore, many surprises are likely to occur in the southern boreal forest over the next century, with major impacts on forest productivity, ecosystem services, and wildlife habitat.

Download Full-text

Effects of Spatial Resolution on Burned Forest Classification With ICESat-2 Photon Counting Data

Frontiers in Remote Sensing ◽

10.3389/frsen.2021.666251 ◽

2021 ◽

Vol 2 ◽

Author(s):

Meng Liu ◽

Sorin Popescu ◽

Lonesome Malambo

Keyword(s):

Climate Change ◽

Boreal Forest ◽

Spatial Resolution ◽

Temperate Forest ◽

Canopy Structure ◽

Segment Length ◽

Retrieval Algorithm ◽

Vegetation Height ◽

Forest Classification ◽

Burned Forest

Accurately monitoring forest fire activities is critical to understanding carbon dynamics and climate change. Three-dimensional (3D) canopy structure changes caused by fire make it possible to adopt Light Detection and Ranging (LiDAR) in burned forest classification. This study focuses on the effects of spatial resolution when using LiDAR data to differentiate burned and unburned forests. The National Aeronautics and Space Administration’s (NASA) Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission provides LiDAR datasets such as the geolocated photon data (ATL03) and the land vegetation height product (ATL08), which were used in this study. The ATL03 data were filtered by two algorithms: the ATL08 algorithm (ILV) and the adaptive ground and canopy height retrieval algorithm (AGCH), producing classified canopy points and ground points. Six typical spatial resolutions: 10, 30, 60, 100, 200, and 250 m were employed to divide the classified photon points into separate segments along the track. Twenty-six canopy related metrics were derived from each segment. Sentinel-2 images were used to provide reference land cover maps. The Random Forest classification method was employed to classify burned and unburned segments in the temperate forest in California and the boreal forest in Alberta, respectively. Both weak beams and strong beams of ICESat-2 data were included in comparisons. Experiment results show that spatial resolution can significantly influence the canopy structures we detected. Classification accuracies increase along with coarser spatial resolutions and saturate at 100 m segment length, with overall accuracies being 79.43 and 92.13% in the temperate forest and the boreal forest, respectively. Classification accuracies based on strong beams are higher than those of using weak beams due to a larger point density in strong beams. The two filtering algorithms present comparable accuracies in burned forest classification. This study demonstrates that spatial resolution is a critical factor to consider when using spaceborne LiDAR for canopy structure characterization and classification, opening an avenue for improved measurement of forest structures and evaluation of terrestrial vegetation responses to climate change.

Download Full-text

Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

Biogeosciences ◽

10.5194/bg-9-4773-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 4773-4785 ◽

Cited By ~ 16

Author(s):

F. Lidman ◽

C. M. Mörth ◽

H. Laudon

Keyword(s):

Boreal Forest ◽

Stream Water ◽

Spatiotemporal Variability ◽

Forest Landscape ◽

Order Stream ◽

Forest Region ◽

Boreal Streams ◽

Wide Range ◽

Hydrogen Carbonate ◽

Mineral Soils

Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2) up to a fourth-order stream (67 km2). Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, suggesting that the concentrations of uranium and thorium in mineral soils are similar throughout the catchment. The fluxes of uranium and thorium were compared to a wide range of parameters characterising the investigated catchments and the chemistry of the stream water, e.g. soil concentrations of these elements, pH, TOC (total organic carbon), Al, Si and hydrogen carbonate, but it was concluded that the spatial variabilities in the fluxes of both uranium and thorium mainly were controlled by wetlands. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal wetlands that is large enough to control the transport of these elements. On the landscape scale approximately 65–80% of uranium and 55–65% of thorium entering a wetland were estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands was estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40%, indicating that wetlands play an important role for the biogeochemical cycling of uranium and thorium in the boreal forest landscape. The atmospheric deposition of uranium and thorium was also quantified, and its contribution to boreal streams was found to be low compared to weathering.

Download Full-text

Climate-Biome Envelope Shifts Create Enormous Challenges and Novel Opportunities for Conservation

Forests ◽

10.3390/f11091015 ◽

2020 ◽

Vol 11 (9) ◽

pp. 1015

Author(s):

Ryan Toot ◽

Lee E. Frelich ◽

Ethan E. Butler ◽

Peter B. Reich

Keyword(s):

Great Lakes ◽

Boreal Forest ◽

Protected Areas ◽

Temperate Forest ◽

Mixed Forest ◽

Great Lakes Region ◽

Recent Climate ◽

Normal Period ◽

Western Great Lakes ◽

Envelope Model

Research Highlights: We modeled climate-biome envelopes at high resolution in the Western Great Lakes Region for recent and future time-periods. The projected biome shifts, in conjunction with heterogeneous distribution of protected land, may create both great challenges for conservation of particular ecosystems and novel conservation opportunities. Background and Objectives: Climate change this century will affect the distribution and relative abundance of ecological communities against a mostly static background of protected land. We developed a climate-biome envelope model using a priori climate-vegetation relationships for the Western Great Lakes Region (Minnesota, Wisconsin and Michigan USA and adjacent Ontario, Canada) to predict potential biomes and ecotones—boreal forest, mixed forest, temperate forest, prairie–forest border, and prairie—for a recent climate normal period (1979–2013) and future conditions (2061–2080). Materials and Methods: We analyzed six scenarios, two representative concentration pathways (RCP)—4.5 and 8.5, and three global climate models to represent cool, average, and warm scenarios to predict climate-biome envelopes for 2061–2080. To assess implications of the changes for conservation, we analyzed the amount of land with climate suited for each of the biomes and ecotones both region-wide and within protected areas, under current and future conditions. Results: Recent biome boundaries were accurately represented by the climate-biome envelope model. The modeled future conditions show at least a 96% loss in areas suitable for the boreal and mixed forest from the region, but likely gains in areas suitable for temperate forest, prairie–forest border, and prairie. The analysis also showed that protected areas in the region will most likely lose most or all of the area, 18,692 km2, currently climatically suitable for boreal forest. This would represent an enormous conservation loss. However, conversely, the area climatically suitable for prairie and prairie–forest border within protected areas would increase up to 12.5 times the currently suitable 1775 km2. Conclusions: These results suggest that retaining boreal forest in potential refugia where it currently exists and facilitating transition of some forests to prairie, oak savanna, and temperate forest should both be conservation priorities in the northern part of the region.

Download Full-text