Reduced turnover rate of topsoil organic carbon in old-growth forests: a case study in subtropical China

Abstract Background Old-growth forests are irreplaceable with respect to climate change mitigation and have considerable carbon (C) sink potential in soils. However, the relationship between the soil organic carbon (SOC) turnover rate and forest development is poorly understood, which hinders our ability to assess the C sequestration capacity of soil in old-growth forests. Methods In this study, we evaluated the SOC turnover rate by calculating the isotopic enrichment factor β (defined as the slope of the regression between 13C natural abundance and log-transformed C concentrations) along 0–30 cm soil profiles in three successional forests in subtropical China. A lower β (steeper slope) is associated with a higher turnover rate. The three forests were a 60-year-old P. massoniana forest (PF), a 100-year-old coniferous and broadleaved mixed forest (MF), and a 400-year-old monsoon evergreen broadleaved forest (BF). We also analyzed the soil physicochemical properties in these forests to examine the dynamics of SOC turnover during forest succession and the main regulators. Results The β value for the upper 30-cm soils in the BF was significantly (p < 0.05) higher than that in the PF, in addition to the SOC stock, although there were nonsignificant differences between the BF and MF. The β value was significantly (p < 0.05) positively correlated with the soil recalcitrance index, total nitrogen, and available nitrogen contents but was significantly (p < 0.01) negatively correlated with soil pH. Conclusions Our results demonstrate that SOC has lower turnover rates in old-growth forests, accompanied by higher soil chemical recalcitrance, nitrogen status, and lower soil pH. This finding helps to elucidate the mechanism underlying C sequestration in old-growth forest soils, and emphasizes the important value of old-growth forests among global C sinks.

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Compared to Wildfire, Management Practices Reduced Old-Growth Forest Diversity and Functionality in Primary Boreal Landscapes of Eastern Canada

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2021.639397 ◽

2021 ◽

Vol 4 ◽

Author(s):

Maxence Martin ◽

Pierre Grondin ◽

Marie-Claude Lambert ◽

Yves Bergeron ◽

Hubert Morin

Keyword(s):

Boreal Forests ◽

Economic Value ◽

Industrial Scale ◽

Old Growth ◽

Ecosystem Based Management ◽

Old Growth Forest ◽

Old Growth Forests ◽

Boreal Landscapes ◽

The Impact ◽

Primary Forests

Large primary forest residuals can still be found in boreal landscapes. Their areas are however shrinking rapidly due to anthropogenic activities, in particular industrial-scale forestry. The impacts of logging activities on primary boreal forests may also strongly differ from those of wildfires, the dominant stand-replacing natural disturbance in these forests. Since industrial-scale forestry is driven by economic motives, there is a risk that stands of higher economic value will be primarily harvested, thus threatening habitats, and functions related to these forests. Hence, the objective of this study was to identify the main attributes differentiating burned and logged stands prior to disturbance in boreal forests. The study territory lies in the coniferous and closed-canopy boreal forest in Québec, Canada, where industrial-scale logging and wildfire are the two main stand-replacing disturbances. Based on Québec government inventories of primary forests, we identified 427 transects containing about 5.5 circular field plots/transect that were burned or logged shortly after being surveyed, between 1985 and 2016. Comparative analysis of the main structural and environmental attributes of these transects highlighted the strong divergence in the impact of fire and harvesting on primary boreal forests. Overall, logging activities mainly harvested forests with the highest economic value, while most burned stands were low to moderately productive or recently disturbed. These results raise concerns about the resistance and resilience of remnant primary forests within managed areas, particularly in a context of disturbance amplification due to climate change. Moreover, the majority of the stands studied were old-growth forests, characterized by a high ecological value but also highly threatened by anthropogenic disturbances. A loss in the diversity and functionality of primary forests, and particularly the old-growth forests, therefore adds to the current issues related to these ecosystems. Since 2013, the study area is under ecosystem-based management, which implies that there have been marked changes in forestry practices. Complementary research will be necessary to assess the capacity of ecosystem-based management to address the challenges identified in our study.

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Recalling open old growth forests in the Southeastern Mixed Forest province of the United States

Ecoscience ◽

10.1080/11956860.2018.1499282 ◽

2018 ◽

Vol 26 (1) ◽

pp. 11-22 ◽

Cited By ~ 8

Author(s):

Brice B. Hanberry ◽

Robert F. Brzuszek ◽

H. Thomas Foster ◽

Timothy J. Schauwecker

Keyword(s):

United States ◽

Mixed Forest ◽

The United States ◽

Old Growth ◽

Old Growth Forests

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Boreal old-growth forest structural diversity challenges aerial photographic survey accuracy

Canadian Journal of Forest Research ◽

10.1139/cjfr-2019-0177 ◽

2020 ◽

Vol 50 (2) ◽

pp. 155-169 ◽

Cited By ~ 4

Author(s):

Maxence Martin ◽

Nicole J. Fenton ◽

Hubert Morin

Keyword(s):

Sustainable Forest Management ◽

Forest Succession ◽

Structural Diversity ◽

Aerial Survey ◽

Old Growth ◽

Tree Species Composition ◽

Forest Inventories ◽

Old Growth Forest ◽

Aerial Surveys ◽

Old Growth Forests

The erosion of old-growth forests in boreal managed landscapes is a major issue currently faced by forest managers; however, resolving this problem requires accurate surveys. The intention of our study was to determine if historic operational aerial forest surveys accurately identified boreal old-growth forests in Quebec, Canada. We first compared stand successional stages (even-aged vs. old-growth) in two aerial surveys performed in 1968 (preindustrial aerial survey) and 2007 (modern aerial survey) on the same 2200 km2 territory. Second, we evaluated the accuracy of the modern aerial survey by comparing its results with those of 74 field plots sampled in the study territory between 2014 and 2016. The two aerial surveys differed significantly; 80.8% of the undisturbed stands that were identified as “old-growth” in the preindustrial survey were classified as “even-aged” in the modern survey, and 60% of the stands identified as “old-growth” by field sampling were also erroneously identified as “even-aged” by the modern aerial survey. The scarcity of obvious old-growth attributes in boreal old-growth forests, as well as poorly adapted modern aerial survey criteria (i.e., criteria requiring high vertical stratification and significant changes in tree species composition along forest succession), were the main factors explaining these errors. It is therefore likely that most of Quebec’s boreal old-growth forests are currently not recognized as such in forest inventories, challenging the efficacy of sustainable forest management policies.

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Species Association of the Dominant Tree Species in an Old-Growth Forest and Implications for Enrichment Planting for the Restoration of Natural Degraded Forest in Subtropical China

Forests ◽

10.3390/f10110957 ◽

2019 ◽

Vol 10 (11) ◽

pp. 957 ◽

Cited By ~ 2

Author(s):

Liu ◽

Zhu ◽

Wang ◽

Ma ◽

Meng

Keyword(s):

Tree Species ◽

Rank Correlation ◽

Economic Benefits ◽

Natural Forests ◽

Subtropical China ◽

Old Growth ◽

Species Association ◽

Old Growth Forest ◽

Enrichment Planting ◽

Adult Trees

Subtropical natural forests are unique due to their ecological and economic functions. However, most of these forests are highly degraded, which impairs the ability to provide ecological and economic benefits. Enrichment planting is an important approach to restore natural degraded forests. Species arrangement is of great importance to inform enrichment planting. Species association refers to the interrelationship of different species occupying a habitat and is a static description of the organic connection formed by the interaction of species. Species association, therefore, provides a scientific basis for species arrangement in enrichment planting. Additionally, because an old-growth forest is a climax community that has attained great age without significant disturbance, the species association in an old-growth forest can provide valuable information on the reference conditions for forest management. In this study, the species association between dominant tree species (including saplings and adult trees) was investigated in an old-growth forest in the Gutianshan National Nature Reserve in Zhejiang province in subtropical China. The objective of the study was to inform species arrangement for enrichment planting. The result showed that the overall species association exhibited a significant net positive association, indicating a dynamic balance of stable structure and species composition in the old-growth forest. Additionally, the pairwise species association was examined using the χ2 test, the Dice index, and Spearman’s rank correlation coefficient; significant positive and negative pairwise species associations were detected. Based on the species association and the light requirements of the tree species, an optimal species arrangement was determined to support enrichment planting for restoring natural degraded forests. It is expected that the results of this study will contribute to the restoration of natural degraded forests in subtropical China.

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Fertility Status of Groundnut Growing Calcareous Vertisols of Dharwad District, Karnataka

International Research Journal of Pure and Applied Chemistry ◽

10.9734/irjpac/2020/v21i1430243 ◽

2020 ◽

pp. 7-19

Author(s):

V. Manasa ◽

N. S. Hebsur ◽

P. L. Patil ◽

M. Hebbara ◽

B. N. Aravind Kumar ◽

...

Keyword(s):

Organic Carbon ◽

Soil Ph ◽

Calcareous Soils ◽

Chemical Properties ◽

Nutrient Status ◽

Soil Survey ◽

Available Phosphorus ◽

Available Nitrogen ◽

Caco3 Content ◽

Nutrient Index

A soil survey was carried out in different groundnut growing calcareous Vertisols of Dharwad district, Karnataka, India. One hundred surface composite soil samples were collected from five talukas (mandal) of Dharwad district and analyzed for soil chemical properties and nutrient status. The results showed that soil pH, electrical conductivity, organic carbon, free CaCO3 content ranged from 6.9-8.9, 0.15-1.79 dS m-1, 2.40-9.10 g kg-1, 5.8 -22.2 respectively across the regions. Available nitrogen, phosphorus (P2O5), potassium (K2O) and sulphur contents widely varied from 107-268, 18.5 - 56.0 and 386- 876, 14.8- 41.0 kg ha-1, respectively. On the basis of nutrient index values, groundnut growing calcareous soils of Dharwad were categorized as deficient in available nitrogen, medium in available phosphorus and high in available potassium. Most of the samples were deficient in available Fe and Zn whereas DTPA-extractable Cu and Mn were above the critical limits. A significant and positive correlation was found between organic carbon and available nitrogen (r=0.730**). However, a negative correlation was observed between Soil pH and micro nutrients while CaCO3 was negatively correlated with available iron (r=-0.31**).

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Bryophyte Conservation in Managed Boreal Landscapes: Fourteen-Year Impacts of Partial Cuts on Epixylic Bryophytes

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2021.674887 ◽

2021 ◽

Vol 4 ◽

Author(s):

Jeffrey Opoku-Nyame ◽

Alain Leduc ◽

Nicole J. Fenton

Keyword(s):

Species Composition ◽

Coarse Woody Debris ◽

Black Spruce ◽

Woody Debris ◽

Permanent Plots ◽

Old Growth ◽

Clear Cut ◽

Old Growth Forest ◽

Old Growth Forests ◽

Over Time

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.

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Dissolved organic carbon production and flux under long-term litter manipulations in a Pacific Northwest old-growth forest

Biogeochemistry ◽

10.1007/s10533-020-00667-6 ◽

2020 ◽

Vol 149 (1) ◽

pp. 75-86

Author(s):

Lucas R. Evans ◽

Derek Pierson ◽

Kate Lajtha

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Pacific Northwest ◽

Old Growth ◽

Carbon Production ◽

Old Growth Forest

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Impacts of logging on soil organic carbon and heterotrophic respiration in tropical forests in Borneo

10.5194/egusphere-egu2020-10276 ◽

2020 ◽

Author(s):

Sylvia H. Vetter ◽

Yit Arn Teh ◽

Michael Martin ◽

Dafydd M. O. Elias ◽

Terhi Riutta ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Respiration ◽

Net Primary Productivity ◽

Spatial Modelling ◽

Selective Logging ◽

Heterotrophic Respiration ◽

Old Growth ◽

Old Growth Forest ◽

Logged Forest

Selective logging is the practice of extracting selected commercial trees from natural production forests. The intensity of logging correlates with a reduction in biodiversity, wood production and biomass stocks. Less is known about the relationship of logging to soil organic carbon (SOC) and how it changes or recovers over time. Empirical measurements in Borneo provided SOC, soil respiration, aboveground and belowground net primary productivity (NPP) from intact old-growth forest (OGF) as well as from moderately to heavily logged (LOG) forest sites. Soil carbon (C) content and heterotrophic respiration (Rh) was higher in LOG sites than in OGF sites. Moderately logged forest (logged > 10 years ago) contained more SOC than heavily logged forest (logged approx. 7 years ago). NPP was used to estimate the C input to the soil. All these data were used to test the biochemical model ECOSSE (Estimating Carbon in Organic Soils &#8211; Sequestration and Emissions) to calculate SOC for the study sites. The model performed well in simulating the soil respiration of OGF and generated acceptable results for LOG sites in the validation process. The results for logged forests showed an increase in Rh over the first 15 years, with some sites showing either a further increase over the next 15 years or stabilizing at a higher level compared to pre-disturbance conditions for other sites. However, for all modelled cases, a break was observed after 30 years, when Rh decreased to a lower level (but not as low as for OGF) before reaching a new equilibrium. At the same time, SOC begins to increase. Spatial modelling showed the results for Borneo under logged conditions and the potential of storing C if logging was reduced. Only 22% of Borneo is under old-growth forest; the results show moderate to high C losses if this region is subjected to logging. Overall, the results show the disturbance of SOC and Rh through logging over periods longer than 30 years.

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The eastern boreal old-growth balsam fir forest: a distinct ecosystem

Canadian Journal of Botany ◽

10.1139/b04-063 ◽

2004 ◽

Vol 82 (6) ◽

pp. 830-849 ◽

Cited By ~ 31

Author(s):

Mireille Desponts ◽

Geneviève Brunet ◽

Louis Bélanger ◽

Mathieu Bouchard

Keyword(s):

Plant Species ◽

Balsam Fir ◽

Old Growth ◽

Saprophytic Fungi ◽

Old Growth Forest ◽

Second Growth ◽

Old Growth Forests ◽

Gaspe Peninsula ◽

Pristine Forest ◽

Gaspé Peninsula

The objective of this project was to assess the importance of pristine forests in maintaining the botanical biodiversity of the humid boreal balsam fir forest of eastern Canada. The study was based on a comparative analysis of silviculturally mature second-growth stands and pristine forest stands at two stages of development (senescent and old growth) in the Gaspé Peninsula. The structure and composition of the stands was described, and the abundance of structural attributes evaluated. The communities of nonvascular plant species (mosses, liverworts), lichens, and saprophytic fungi were compared. The study demonstrated that the pristine forest landscape studied was composed largely of old-growth and senescent stands. Old-growth forests are differentiated by their irregular structure. The results regarding nonvascular plant species, lichens, and saprophytic fungi show higher species diversity in old-growth forests, corresponding to higher habitat diversity. Species assemblages were comparable between the pristine forests, but different from those of second-growth stands. Rare species are found more frequently in the old-growth forests. The results indicate that the old-growth balsam fir stands of the Gaspé Peninsula constitute critical habitats for maintaining a large number of species threatened by the gradual disappearance of primeval stands.Key words: forest management, biodiversity, old-growth forest, humid boreal fir forest, nonvascular plants.

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