Hemlock loss due to the hemlock woolly adelgid does not affect ecosystem C storage but alters its distribution

Raymer, Poliana C. L.; Orwig, David A.; Finzi, Adrien C.

doi:10.1890/es12-00362.1

Cited by 20 publications

(50 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the objective of this paper is to further our understanding of these fluxes, focusing specifically on aboveground net primary production, decomposition, and soil respiration. This research builds on prior work using a comparative approach showing that there was little change in the quantity but significant variations in the distribution of C stored in biomass, coarse woody debris, and soil pools across a stand-age and species-composition gradient of hemlock to black birch (Raymer et al 2013). …”

Section: Introductionmentioning

confidence: 93%

“…We quantified C fluxes in: (1) a primary (old-growth) hemlock stand .230 years old, representing potential future characteristics of a developing secondary-hemlock stand; (2) a 132-year-old secondary-hemlock stand representing the starting point of HWA infestation for most hemlock forests in this region; (3) a girdled hemlock stand, representing an early stage following hemlock death (5 years); (4) a 18-year-old post-HWA hemlock stand that currently has vigorously regrowing black birch saplings up to 5 m in height; and (5) a black birch stand ;135 years old, growing on former pastureland (Table 1 (Ellison et al 2010) and was intended to simulate a gradual death of standing hemlock Raymer et al (2013). Briefly, the primary-hemlock and post-HWA stands were once used as woodlots and the secondary hemlock, girdled, and black birch stands developed following pastureland abandonment.…”

Section: Stands and Climatementioning

confidence: 99%

“…Ten trees were cored in each plot (200 trees total) in proportion to the relative importance value (RIV) and diameter distribution of the dominant species in each plot (Raymer et al 2013). For each plot, RIV was obtained by averaging the species' relative basal area and relative density (Orwig and Foster 1998).…”

Section: Net Primary Productionmentioning

confidence: 99%

“…Speciesspecific allometric equations (Raymer et al 2013) were used to calculate the production of woody biomass in each plot.…”

Section: Net Primary Productionmentioning

confidence: 99%

“…Foliage biomass increment was estimated from the allometric equations presented in Raymer et al (2013) and foliage turnover was estimated on-site using litterfall dry mass. Litter baskets were 39 cm in diameter and 45 cm high, with an additional 5-10 cm gap between the ground and the collecting fiberglass mesh to avoid litter moisture.…”

Section: Net Primary Productionmentioning

confidence: 99%

See 4 more Smart Citations

Net primary production and soil respiration in New England hemlock forests affected by the hemlock woolly adelgid

et al. 2014

Self Cite

View full text Add to dashboard Cite

Abstract. The abundance of eastern hemlock (Tsuga canadensis) in eastern US forests has declined since the 1950s owing to the introduction of the non-native insect, hemlock woolly adelgid (HWA, Adelges tsugae). In southern New England, eastern hemlock is being replaced by the deciduous tree species, black birch (Betula lenta). To date there is little understanding of whether hemlock loss will fundamentally alter ecosystem C balance and component fluxes. In this study, we use a comparative approach to study potential changes in C fluxes and N cycling associated with HWA-induced hemlock decline and replacement. The stands include primary-and secondary-growth hemlock forests (.230 and 132 years old, respectively), recently disturbed stands (5 and 18 years old) that now have rapidly growing black birch saplings, and a mature black birch stand of age similar to the second-growth hemlock stand. We found that aboveground net primary production was higher in the aggrading black birch stand and significantly so at 18-years post-HWA compared to the secondary-hemlock stand it would likely replace. Rapid forest regrowth was accompanied by significantly higher rates of N uptake from the soil but also higher N-use efficiency because most of the N taken up from the soil was allocated to the production of wood with a high C-to-N ratio. In contrast to patterns of aboveground production, the rate of soil respiration was lowest in the young stands and not significantly different from the second-growth hemlock stand, suggesting little net effect of stand replacement on soil C efflux. The leaf litter decomposition study showed that black birch litter decomposed more rapidly than hemlock litter but that there was no effect of stand type on the rate of decomposition. Analyses of extracellular microbial exoenzyme activity painted a more nuanced pattern of variation among stands, with fine root biomass the only weakly explanatory variable. In combination with our prior work on C stocks, these results suggest that forests affected by HWA in southern New England will remain a sink for atmospheric CO 2 despite reorganization of stand structure and species composition.

show abstract

Section: Introductionmentioning

confidence: 93%

Section: Stands and Climatementioning

confidence: 99%

Section: Net Primary Productionmentioning

confidence: 99%

“…Speciesspecific allometric equations (Raymer et al 2013) were used to calculate the production of woody biomass in each plot.…”

Section: Net Primary Productionmentioning

confidence: 99%

Section: Net Primary Productionmentioning

confidence: 99%

See 3 more Smart Citations

Net primary production and soil respiration in New England hemlock forests affected by the hemlock woolly adelgid

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

Logging response alters trajectories of reorganization after loss of a foundation tree species

Barker Plotkin,

Orwig,

MacLean

et al. 2024

Ecological Applications

Self Cite

View full text Add to dashboard Cite

Forest insect outbreaks cause large changes in ecosystem structure, composition, and function. Humans often respond to insect outbreaks by conducting salvage logging, which can amplify the immediate effects, but it is unclear whether logging will result in lasting differences in forest structure and dynamics when compared with forests affected only by insect outbreaks. We used 15 years of data from an experimental removal of Tsuga canadensis (L.) Carr. (Eastern hemlock), a foundation tree species within eastern North American forests, and contrasted the rate, magnitude, and persistence of response trajectories between girdling (emulating mortality from insect outbreak) and timber harvest treatments. Girdling and logging were equally likely to lead to large changes in forest structure and dynamics, but logging resulted in faster rates of change. Understory light increases and community composition changes were larger and more rapid in the logged plots. Tree seedling and understory vegetation abundance increased more in the girdled plots; this likely occurred because seedlings grew rapidly into the sapling‐ and tree‐size classes after logging and quickly shaded out plants on the forest floor. Downed deadwood pools increased more after logging but standing deadwood pools increased dramatically after girdling. Understory light levels remained elevated for a longer time after girdling. Perhaps because the window of opportunity for understory species to establish was longer in the girdled plots, total species richness increased more in the girdled than logged plots. Despite the potential for greater diversity in the girdled plots, Betula lenta L. (black birch) was the most abundant tree species recruited into the sapling‐ and tree‐size classes in both the girdled and logged plots and is poised to dominate the new forest canopy. The largest difference between the girdling and logging treatments—deadwood structure and quantity—will persist and continue to bolster aboveground carbon storage and structural and habitat diversity in the girdled plots. Human responses to insect outbreaks hasten forest reorganization and remove structural resources that may further alter forest response to ongoing climate stress and future disturbances.

show abstract

Carbon budget of the Harvard Forest Long‐Term Ecological Research site: pattern, process, and response to global change

Finzi

Giasson

Plotkin

et al. 2020

Ecological Monographs

Self Cite

View full text Add to dashboard Cite

How, where, and why carbon (C) moves into and out of an ecosystem through time are long-standing questions in biogeochemistry. Here, we bring together hundreds of thousands of C-cycle observations at the Harvard Forest in central Massachusetts, USA, a mid-latitude landscape dominated by 80-120-yr-old closed-canopy forests. These data answered four questions: (1) where and how much C is presently stored in dominant forest types; (2) what are current rates of C accrual and loss; (3) what biotic and abiotic factors contribute to variability in these rates; and (4) how has climate change affected the forest's C cycle? Harvard Forest is an active C sink resulting from forest regrowth following land abandonment. Soil and tree biomass comprise nearly equal portions of existing C stocks. Net primary production (NPP) averaged 680-750 g CÁm À2 Áyr À1 ; belowground NPP contributed 38-47% of the total, but with large uncertainty. Mineral soil C measured in the same inventory plots in 1992 and 2013 was too heterogeneous to detect change in soil-C pools; however, radiocarbon data suggest a small but persistent sink of 10-30 g CÁm À2 Áyr À1. Net ecosystem production (NEP) in hardwood stands averaged~300 g CÁm À2 Áyr À1. NEP in hemlock-dominated forests averaged 450 g CÁm À2 Áyr À1 until infestation by the hemlock woolly adelgid turned these stands into a net C source. Since 2000, NPP has increased by 26%. For the period 1992-2015, NEP increased 93%. The increase in mean annual temperature and growing season length alone accounted for~30% of the increase in productivity. Interannual variations in GPP and NEP were also correlated with increases in red oak biomass, forest leaf area, and canopy-scale lightuse efficiency. Compared to long-term global change experiments at the Harvard Forest, the C sink in regrowing biomass equaled or exceeded C cycle modifications imposed by soil warming, N saturation, and hemlock removal. Results of this synthesis and comparison to simulation models suggest that forests across the region are likely to accrue C for decades to come but may be disrupted if the frequency or severity of biotic and abiotic disturbances increases.

show abstract

Hemlock loss due to the hemlock woolly adelgid does not affect ecosystem C storage but alters its distribution

Cited by 20 publications

References 49 publications

Net primary production and soil respiration in New England hemlock forests affected by the hemlock woolly adelgid

Net primary production and soil respiration in New England hemlock forests affected by the hemlock woolly adelgid

Logging response alters trajectories of reorganization after loss of a foundation tree species

Carbon budget of the Harvard Forest Long‐Term Ecological Research site: pattern, process, and response to global change

Contact Info

Product

Resources

About