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Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance.

Turner DP, Ritts WD, Kennedy RE, Gray AN, Yang Z - Carbon Balance Manag (2015)

Bottom Line: Localized carbon source areas were associated with recent harvests and fire.Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years.The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Ecosystems and Society, Oregon State University, 97331 Corvallis, OR USA.

ABSTRACT

Background: Disturbance is a key influence on forest carbon dynamics, but the complexity of spatial and temporal patterns in forest disturbance makes it difficult to quantify their impacts on carbon flux over broad spatial domains. Here we used a time series of Landsat remote sensing images and a climate-driven carbon cycle process model to evaluate carbon fluxes at the ecoregion scale in western Oregon.

Results: Thirteen percent of total forest area in the West Cascades ecoregion was disturbed during the reference interval (1991-2010). The disturbance regime was dominated by harvesting (59 % of all area disturbed), with lower levels of fire (23 %), and pest/pathogen mortality (18 %). Ecoregion total Net Ecosystem Production was positive (a carbon sink) in all years, with greater carbon uptake in relatively cool years. Localized carbon source areas were associated with recent harvests and fire. Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years. Net Ecosystem Carbon Balance (i.e. change in carbon stocks) was more positive on public that private forestland, because of a lower disturbance rate, and more positive in the decade of the 1990s than in the warmer and drier 2000s because of lower net ecosystem production and higher direct fire emissions in the 2000s.

Conclusion: Despite recurrent disturbances, the West Cascades ecoregion has maintained a positive carbon balance in recent decades. The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

No MeSH data available.


Related in: MedlinePlus

Relationship of mean Net Ecosystem Production (2006-2010) to elevation band
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Fig10: Relationship of mean Net Ecosystem Production (2006-2010) to elevation band

Mentions: In the ecoregion-wide simulations, the majority of the surface area of the WC ecoregion had a positive NEP during the study period (e.g. Fig. 9). NEP tends to decrease as elevation increases (Fig. 10) because of decreasing rates of wood productivity associated with a shorter growing season, and a shift towards older, slower growing, age classes on public lands (Fig. 2b). Carbon sources (negative NEP) are indicated in areas recently burned or harvested.Fig. 9


Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance.

Turner DP, Ritts WD, Kennedy RE, Gray AN, Yang Z - Carbon Balance Manag (2015)

Relationship of mean Net Ecosystem Production (2006-2010) to elevation band
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4442132&req=5

Fig10: Relationship of mean Net Ecosystem Production (2006-2010) to elevation band
Mentions: In the ecoregion-wide simulations, the majority of the surface area of the WC ecoregion had a positive NEP during the study period (e.g. Fig. 9). NEP tends to decrease as elevation increases (Fig. 10) because of decreasing rates of wood productivity associated with a shorter growing season, and a shift towards older, slower growing, age classes on public lands (Fig. 2b). Carbon sources (negative NEP) are indicated in areas recently burned or harvested.Fig. 9

Bottom Line: Localized carbon source areas were associated with recent harvests and fire.Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years.The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Ecosystems and Society, Oregon State University, 97331 Corvallis, OR USA.

ABSTRACT

Background: Disturbance is a key influence on forest carbon dynamics, but the complexity of spatial and temporal patterns in forest disturbance makes it difficult to quantify their impacts on carbon flux over broad spatial domains. Here we used a time series of Landsat remote sensing images and a climate-driven carbon cycle process model to evaluate carbon fluxes at the ecoregion scale in western Oregon.

Results: Thirteen percent of total forest area in the West Cascades ecoregion was disturbed during the reference interval (1991-2010). The disturbance regime was dominated by harvesting (59 % of all area disturbed), with lower levels of fire (23 %), and pest/pathogen mortality (18 %). Ecoregion total Net Ecosystem Production was positive (a carbon sink) in all years, with greater carbon uptake in relatively cool years. Localized carbon source areas were associated with recent harvests and fire. Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years. Net Ecosystem Carbon Balance (i.e. change in carbon stocks) was more positive on public that private forestland, because of a lower disturbance rate, and more positive in the decade of the 1990s than in the warmer and drier 2000s because of lower net ecosystem production and higher direct fire emissions in the 2000s.

Conclusion: Despite recurrent disturbances, the West Cascades ecoregion has maintained a positive carbon balance in recent decades. The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

No MeSH data available.


Related in: MedlinePlus